BoundField.cs source code in C# .NET

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Code:

/ Dotnetfx_Vista_SP2 / Dotnetfx_Vista_SP2 / 8.0.50727.4016 / DEVDIV / depot / DevDiv / releases / whidbey / NetFxQFE / ndp / fx / src / xsp / System / Web / UI / WebControls / BoundField.cs / 1 / BoundField.cs

                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

namespace System.Web.UI.WebControls { 
 
    using System;
    using System.Collections; 
    using System.Collections.Specialized;
    using System.ComponentModel;
    using System.Globalization;
    using System.Security.Permissions; 
    using System.Web.Util;
 
 
    /// 
    /// Creates a field bounded to a data field in a . 
    /// 
    [AspNetHostingPermission(SecurityAction.LinkDemand, Level=AspNetHostingPermissionLevel.Minimal)]
    [AspNetHostingPermission(SecurityAction.InheritanceDemand, Level=AspNetHostingPermissionLevel.Minimal)]
    public class BoundField : DataControlField { 

 
        ///  
        ///    Specifies a string that represents "this". This field is read-only. 
        ///  
        public static readonly string ThisExpression = "!";

        private PropertyDescriptor _boundFieldDesc;
        string _dataField; 
        string _dataFormatString;
        bool _htmlEncode; 
        bool _htmlEncodeSet = false; 
        bool _suppressHeaderTextFieldChange;
        private bool _htmlEncodeFormatString; 
        private bool _htmlEncodeFormatStringSet;


        ///  
        /// Initializes a new instance of a  class.
        ///  
        public BoundField() { 
        }
 
        /// 
        ///     Indicates whether to apply the DataFormatString in edit mode
        /// 
        [ 
            WebCategory("Behavior"),
            DefaultValue(false), 
            WebSysDescription(SR.BoundField_ApplyFormatInEditMode) 
        ]
        public virtual bool ApplyFormatInEditMode { 
            get {
                object o = ViewState["ApplyFormatInEditMode"];
                if (o != null) {
                    return (bool)o; 
                }
                return false; 
            } 
            set {
                ViewState["ApplyFormatInEditMode"] = value; 
            }
        }

 
        /// 
        ///    Gets or sets the property that determines whether the BoundField treats empty string as 
        ///    null when the field values are extracted. 
        /// 
        [ 
            WebCategory("Behavior"),
            DefaultValue(true),
            WebSysDescription(SR.BoundField_ConvertEmptyStringToNull)
        ] 
        public virtual bool ConvertEmptyStringToNull {
            get { 
                object o = ViewState["ConvertEmptyStringToNull"]; 
                if (o != null) {
                    return (bool)o; 
                }
                return true;
            }
            set { 
                ViewState["ConvertEmptyStringToNull"] = value;
            } 
        } 

 
        /// 
        ///     Gets or sets the field name from the data model bound to this field.
        /// 
        [ 
            WebCategory("Data"),
            DefaultValue(""), 
            TypeConverter("System.Web.UI.Design.DataSourceViewSchemaConverter, " + AssemblyRef.SystemDesign), 
            WebSysDescription(SR.BoundField_DataField)
        ] 
        public virtual string DataField {
            get {
                if (_dataField == null) {
                    object o = ViewState["DataField"]; 
                    if (o != null)
                        _dataField = (string)o; 
                    else 
                        _dataField = String.Empty;
                    } 
                return _dataField;
            }
            set {
                if (!String.Equals(value, ViewState["DataField"])) { 
                    ViewState["DataField"] = value;
                    _dataField = value; 
                    OnFieldChanged(); 
                }
            } 
        }


        ///  
        ///    Gets or sets the display format of data in this
        ///       field. 
        ///  
        [
            WebCategory("Data"), 
            DefaultValue(""),
            WebSysDescription(SR.BoundField_DataFormatString)
        ]
        public virtual string DataFormatString { 
            get {
                if (_dataFormatString == null) { 
                    object o = ViewState["DataFormatString"]; 
                    if (o != null)
                        _dataFormatString = (string)o; 
                    else
                        _dataFormatString = String.Empty;
                }
                return _dataFormatString; 
            }
            set { 
                if (!String.Equals(value, ViewState["DataFormatString"])) { 
                    ViewState["DataFormatString"] = value;
                    _dataFormatString = value; 
                    OnFieldChanged();
                }
            }
        } 

 
        ///  
        /// Gets or sets the text displayed in the header of the
        /// System.Web.UI.WebControls.Field. 
        /// 
        public override string HeaderText {
            get {
                return base.HeaderText; 
            }
            set { 
                if (!String.Equals(value, ViewState["HeaderText"])) { 
                    ViewState["HeaderText"] = value;
                    if (!_suppressHeaderTextFieldChange) { 
                        OnFieldChanged();
                    }
                }
            } 
        }
 
        ///  
        /// Gets or sets a property indicating whether data should be HtmlEncoded when it is displayed to the user.
        ///  
        [
        WebCategory("Behavior"),
        DefaultValue(true),
        WebSysDescription(SR.BoundField_HtmlEncode) 
        ]
        public virtual bool HtmlEncode { 
            get { 
                if (!_htmlEncodeSet) {
                    object o = ViewState["HtmlEncode"]; 
                    if (o != null) {
                        _htmlEncode = (bool)o;
                    }
                    else { 
                        _htmlEncode = true;
                    } 
                    _htmlEncodeSet = true; 
                }
                return _htmlEncode; 
            }
            set {
                object oldValue = ViewState["HtmlEncode"];
                if (oldValue == null || (bool)oldValue != value) { 
                    ViewState["HtmlEncode"] = value;
                    _htmlEncode = value; 
                    _htmlEncodeSet = true; 
                    OnFieldChanged();
                } 
            }
        }

        ///  
        /// Gets or sets a property indicating whether the format string should be HtmlEncoded
        /// when it is displayed to the user. 
        ///  
        [
        WebCategory("Behavior"), 
        DefaultValue(true),
        ]
        public virtual bool HtmlEncodeFormatString {
            get { 
                if (!_htmlEncodeFormatStringSet) {
                    object o = ViewState["HtmlEncodeFormatString"]; 
                    if (o != null) { 
                        _htmlEncodeFormatString = (bool)o;
                    } 
                    else {
                        _htmlEncodeFormatString = true;
                    }
                    _htmlEncodeFormatStringSet = true; 
                }
                return _htmlEncodeFormatString; 
            } 
            set {
                object oldValue = ViewState["HtmlEncodeFormatString"]; 
                if (oldValue == null || (bool)oldValue != value) {
                    ViewState["HtmlEncodeFormatString"] = value;
                    _htmlEncodeFormatString = value;
                    _htmlEncodeFormatStringSet = true; 
                    OnFieldChanged();
                } 
            } 
        }
        ///  
        ///    Gets or sets the property that determines what text is displayed if the value
        ///    of the field is null.
        /// 
        [ 
            WebCategory("Behavior"),
            DefaultValue(""), 
            WebSysDescription(SR.BoundField_NullDisplayText) 
        ]
        public virtual string NullDisplayText { 
            get {
                object o = ViewState["NullDisplayText"];
                if (o != null) {
                    return (string)o; 
                }
                return String.Empty; 
            } 
            set {
                if (!String.Equals(value, ViewState["NullDisplayText"])) { 
                    ViewState["NullDisplayText"] = value;
                    OnFieldChanged();
                }
            } 
        }
 
 
        /// 
        ///    Gets or sets the property that prevents modification to data 
        ///       in this field.
        /// 
        [
            WebCategory("Behavior"), 
            DefaultValue(false),
            WebSysDescription(SR.BoundField_ReadOnly) 
        ] 
        public virtual bool ReadOnly {
            get { 
                object o = ViewState["ReadOnly"];
                if (o != null)
                    return (bool)o;
                return false; 
            }
            set { 
                object oldValue = ViewState["ReadOnly"]; 
                if (oldValue == null || (bool)oldValue != value) {
                    ViewState["ReadOnly"] = value; 
                    OnFieldChanged();
                }
            }
        } 

        protected virtual bool SupportsHtmlEncode { 
            get { 
                return true;
            } 
        }

        protected override void CopyProperties(DataControlField newField) {
            ((BoundField)newField).ApplyFormatInEditMode = ApplyFormatInEditMode; 
            ((BoundField)newField).ConvertEmptyStringToNull = ConvertEmptyStringToNull;
            ((BoundField)newField).DataField = DataField; 
            ((BoundField)newField).DataFormatString = DataFormatString; 
            ((BoundField)newField).HtmlEncode = HtmlEncode;
            ((BoundField)newField).HtmlEncodeFormatString = HtmlEncodeFormatString; 
            ((BoundField)newField).NullDisplayText = NullDisplayText;
            ((BoundField)newField).ReadOnly = ReadOnly;

            base.CopyProperties(newField); 
        }
 
        protected override DataControlField CreateField() { 
            return new BoundField();
        } 


        /// 
        /// Extracts the value(s) from the given cell and puts the value(s) into a dictionary.  Indicate includeReadOnly 
        /// to have readonly fields' values inserted into the dictionary.
        ///  
        public override void ExtractValuesFromCell(IOrderedDictionary dictionary, DataControlFieldCell cell, DataControlRowState rowState, bool includeReadOnly) { 
            Control childControl = null;
            string dataField = DataField; 
            object value = null;
            string nullDisplayText = NullDisplayText;

            if (((rowState & DataControlRowState.Insert) != 0) && !InsertVisible) { 
                return;
            } 
 
            if (cell.Controls.Count > 0) {
                childControl = cell.Controls[0]; 

                TextBox editBox = childControl as TextBox;
                if (editBox != null) {
                    value = editBox.Text; 
                }
            } 
            else { 
                if (includeReadOnly == true) {
                    string cellText = cell.Text; 
                    if (cellText == " ") { // nothing HtmlEncodes to  , so we know that this means it was empty.
                        value = String.Empty;
                    }
                    else { 
                        if (SupportsHtmlEncode && HtmlEncode) {
                            value = HttpUtility.HtmlDecode(cellText); 
                        } 
                        else {
                            value = cellText; 
                        }
                    }
                }
            } 

            if (value != null) { 
                if ((value is string) && (((string)value).Length == 0) && ConvertEmptyStringToNull) { 
                    value = null;
                } 

                if (value is string && (string)value == nullDisplayText && nullDisplayText.Length > 0) {
                    value = null;
                } 

                if (dictionary.Contains(dataField)) { 
                    dictionary[dataField] = value; 
                }
                else { 
                    dictionary.Add(dataField, value);
                }
            }
 
        }
 
 
        /// 
        /// Returns the value of the field formatted as text for the cell. 
        /// 
        protected virtual string FormatDataValue(object dataValue, bool encode) {
            string formattedValue = String.Empty;
 
            if (!DataBinder.IsNull(dataValue)) {
                string dataValueString = dataValue.ToString(); 
                string formatting = DataFormatString; 
                int dataValueStringLength = dataValueString.Length;
 
                if (!HtmlEncodeFormatString) {
                    // Back-compat (Whidbey) behavior when HtmlEncodeFormatString=false
                    if (dataValueStringLength > 0 && encode) {
                        dataValueString = HttpUtility.HtmlEncode(dataValueString); 
                    }
 
                    if (dataValueStringLength == 0 && ConvertEmptyStringToNull) { 
                        formattedValue = NullDisplayText;
                    } 
                    else if (formatting.Length == 0) {
                        formattedValue = dataValueString;
                    }
                    else { 
                        if (encode) {
                            formattedValue = String.Format(CultureInfo.CurrentCulture, formatting, dataValueString); 
                        } 
                        else {
                            formattedValue = String.Format(CultureInfo.CurrentCulture, formatting, dataValue); 
                        }
                    }
                }
                else { 
                    // New default behavior (Orcas) when HtmlEncodeFormatString=true
 
                    // If the result is still empty and ConvertEmptyStringToNull=true, replace the value with the NullDisplayText 
                    if (dataValueStringLength == 0 && ConvertEmptyStringToNull) {
                        dataValueString = NullDisplayText; 
                    }
                    else {
                        // If there's a format string, apply it to the raw data value
                        // If there's no format string, then dataValueString already has the right value 
                        if (!String.IsNullOrEmpty(formatting)) {
                            dataValueString = String.Format(CultureInfo.CurrentCulture, formatting, dataValue); 
                        } 

                        // Optionally HTML encode the value (including the format string, if any was applied) 
                        if (!String.IsNullOrEmpty(dataValueString) && encode) {
                            dataValueString = HttpUtility.HtmlEncode(dataValueString);
                        }
                    } 

                    formattedValue = dataValueString; 
                } 
            }
            else { 
                formattedValue = NullDisplayText;
            }

            return formattedValue; 
        }
 
 
        /// 
        /// Returns a value to be used for design-time rendering 
        /// 
        protected virtual object GetDesignTimeValue() {
            return SR.GetString(SR.Sample_Databound_Text);
        } 

 
        ///  
        /// Retrieves the value of the field to be databound to the BoundField.
        ///  
        protected virtual object GetValue(Control controlContainer) {
            Debug.Assert(DataField.Length != 0, "Shouldn't be DataBinding without a DataField");

            object data = null; 
            object dataItem = null;
            string boundField = DataField; 
 
            if (controlContainer == null) {
                throw new HttpException(SR.GetString(SR.DataControlField_NoContainer)); 
            }

            // Get the DataItem from the container
            dataItem = DataBinder.GetDataItem(controlContainer); 

            if (dataItem == null && !DesignMode) { 
                throw new HttpException(SR.GetString(SR.DataItem_Not_Found)); 
            }
            // Get value of field in data item 
            if (_boundFieldDesc == null) {
                if (!boundField.Equals(ThisExpression)) {
                    _boundFieldDesc = TypeDescriptor.GetProperties(dataItem).Find(boundField, true);
                    if ((_boundFieldDesc == null) && !DesignMode) { 
                        throw new HttpException(SR.GetString(SR.Field_Not_Found, boundField));
                    } 
                } 
            }
 
            if (_boundFieldDesc != null && dataItem != null) {
                data = _boundFieldDesc.GetValue(dataItem);
            }
            else { 
                if (DesignMode) {
                    data = GetDesignTimeValue(); 
                } 
                else {
                    data = dataItem; 
                }
            }

            return data; 
        }
 
 
        /// 
        /// Initializes the field and resets member variables. 
        /// 
        public override bool Initialize(bool enableSorting, Control control) {
            base.Initialize(enableSorting, control);
            _boundFieldDesc = null; 
            return false;
        } 
 

        ///  
        /// Initializes a cell in the DataControlField.
        /// 
        public override void InitializeCell(DataControlFieldCell cell, DataControlCellType cellType, DataControlRowState rowState, int rowIndex) {
            string unencodedHeaderText = null; 
            bool changedHeaderText = false;
            bool encode = false; 
            // if this is a header cell and we're htmlEncoding, htmlEncode the HeaderText before the base class tries to render it 
            if (cellType == DataControlCellType.Header && SupportsHtmlEncode && HtmlEncode) {
                unencodedHeaderText = HeaderText; 
                encode = true;
            }

            if (encode && !String.IsNullOrEmpty(unencodedHeaderText)) { 
                _suppressHeaderTextFieldChange = true;
                HeaderText = HttpUtility.HtmlEncode(unencodedHeaderText); 
                changedHeaderText = true; 
            }
            base.InitializeCell(cell, cellType, rowState, rowIndex); 

            // restore the HeaderText property
            if (changedHeaderText) {
                HeaderText = unencodedHeaderText; 
                _suppressHeaderTextFieldChange = false;
            } 
            switch (cellType) { 
                case DataControlCellType.DataCell:
                    InitializeDataCell(cell, rowState); 
                    break;
            }
        }
 

        protected virtual void InitializeDataCell(DataControlFieldCell cell, DataControlRowState rowState) { 
            Control childControl = null; 
            Control boundControl = null;
 
            if (((rowState & DataControlRowState.Edit) != 0 && ReadOnly == false) || (rowState & DataControlRowState.Insert) != 0) {
                //
                TextBox editor = new TextBox();
                editor.ToolTip = HeaderText; 
                childControl = editor;
 
                if (DataField.Length != 0 && (rowState & DataControlRowState.Edit) != 0) { 
                    boundControl = editor;
                } 
            }
            else if (DataField.Length != 0) {
                boundControl = cell;
            } 

            if (childControl != null) { 
                cell.Controls.Add(childControl); 
            }
 
            if (boundControl != null && Visible) {
                boundControl.DataBinding += new EventHandler(this.OnDataBindField);
            }
        } 

 
        ///  
        /// 
        protected virtual void OnDataBindField(object sender, EventArgs e) { 
            Control boundControl = (Control)sender;
            Control controlContainer = boundControl.NamingContainer;

            object data = GetValue(controlContainer); 
            bool encodeValue = SupportsHtmlEncode && HtmlEncode && boundControl is TableCell;
            string dataValue = FormatDataValue(data, encodeValue); 
 
            if (boundControl is TableCell) {
                if (dataValue.Length == 0) { 
                    dataValue = " ";
                }
                ((TableCell)boundControl).Text = dataValue;
            } 
            else {
                if (!(boundControl is TextBox)) { 
                    throw new HttpException(SR.GetString(SR.BoundField_WrongControlType, DataField)); 
                }
 
                if (ApplyFormatInEditMode) {
                    ((TextBox)boundControl).Text = dataValue;
                }
                else { 
                    if (data != null) {
                        ((TextBox)boundControl).Text = data.ToString(); 
                    } 
                }
 
                if (data != null) {
                    // size down the textbox for certain types
                    if (data.GetType().IsPrimitive) {
                        ((TextBox)boundControl).Columns = 5; 
                    }
                } 
            } 
        }
 
        protected override void LoadViewState(object state) {
             // DevDiv Bugs 188902: Clear cached values as they may be stale after ViewState loads.
             _dataField = null;
             _dataFormatString = null; 
             _htmlEncodeSet = false;
             _htmlEncodeFormatStringSet = false; 
 
             base.LoadViewState(state);
        } 

        /// 
        /// Override with an empty body if the field's controls all support callback.
        ///  Otherwise, override and throw a useful error message about why the field can't support callbacks. 
        /// 
        public override void ValidateSupportsCallback() { 
        } 
    }
} 


// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
//------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

namespace System.Web.UI.WebControls { 
 
    using System;
    using System.Collections; 
    using System.Collections.Specialized;
    using System.ComponentModel;
    using System.Globalization;
    using System.Security.Permissions; 
    using System.Web.Util;
 
 
    /// 
    /// Creates a field bounded to a data field in a . 
    /// 
    [AspNetHostingPermission(SecurityAction.LinkDemand, Level=AspNetHostingPermissionLevel.Minimal)]
    [AspNetHostingPermission(SecurityAction.InheritanceDemand, Level=AspNetHostingPermissionLevel.Minimal)]
    public class BoundField : DataControlField { 

 
        ///  
        ///    Specifies a string that represents "this". This field is read-only. 
        ///  
        public static readonly string ThisExpression = "!";

        private PropertyDescriptor _boundFieldDesc;
        string _dataField; 
        string _dataFormatString;
        bool _htmlEncode; 
        bool _htmlEncodeSet = false; 
        bool _suppressHeaderTextFieldChange;
        private bool _htmlEncodeFormatString; 
        private bool _htmlEncodeFormatStringSet;


        ///  
        /// Initializes a new instance of a  class.
        ///  
        public BoundField() { 
        }
 
        /// 
        ///     Indicates whether to apply the DataFormatString in edit mode
        /// 
        [ 
            WebCategory("Behavior"),
            DefaultValue(false), 
            WebSysDescription(SR.BoundField_ApplyFormatInEditMode) 
        ]
        public virtual bool ApplyFormatInEditMode { 
            get {
                object o = ViewState["ApplyFormatInEditMode"];
                if (o != null) {
                    return (bool)o; 
                }
                return false; 
            } 
            set {
                ViewState["ApplyFormatInEditMode"] = value; 
            }
        }

 
        /// 
        ///    Gets or sets the property that determines whether the BoundField treats empty string as 
        ///    null when the field values are extracted. 
        /// 
        [ 
            WebCategory("Behavior"),
            DefaultValue(true),
            WebSysDescription(SR.BoundField_ConvertEmptyStringToNull)
        ] 
        public virtual bool ConvertEmptyStringToNull {
            get { 
                object o = ViewState["ConvertEmptyStringToNull"]; 
                if (o != null) {
                    return (bool)o; 
                }
                return true;
            }
            set { 
                ViewState["ConvertEmptyStringToNull"] = value;
            } 
        } 

 
        /// 
        ///     Gets or sets the field name from the data model bound to this field.
        /// 
        [ 
            WebCategory("Data"),
            DefaultValue(""), 
            TypeConverter("System.Web.UI.Design.DataSourceViewSchemaConverter, " + AssemblyRef.SystemDesign), 
            WebSysDescription(SR.BoundField_DataField)
        ] 
        public virtual string DataField {
            get {
                if (_dataField == null) {
                    object o = ViewState["DataField"]; 
                    if (o != null)
                        _dataField = (string)o; 
                    else 
                        _dataField = String.Empty;
                    } 
                return _dataField;
            }
            set {
                if (!String.Equals(value, ViewState["DataField"])) { 
                    ViewState["DataField"] = value;
                    _dataField = value; 
                    OnFieldChanged(); 
                }
            } 
        }


        ///  
        ///    Gets or sets the display format of data in this
        ///       field. 
        ///  
        [
            WebCategory("Data"), 
            DefaultValue(""),
            WebSysDescription(SR.BoundField_DataFormatString)
        ]
        public virtual string DataFormatString { 
            get {
                if (_dataFormatString == null) { 
                    object o = ViewState["DataFormatString"]; 
                    if (o != null)
                        _dataFormatString = (string)o; 
                    else
                        _dataFormatString = String.Empty;
                }
                return _dataFormatString; 
            }
            set { 
                if (!String.Equals(value, ViewState["DataFormatString"])) { 
                    ViewState["DataFormatString"] = value;
                    _dataFormatString = value; 
                    OnFieldChanged();
                }
            }
        } 

 
        ///  
        /// Gets or sets the text displayed in the header of the
        /// System.Web.UI.WebControls.Field. 
        /// 
        public override string HeaderText {
            get {
                return base.HeaderText; 
            }
            set { 
                if (!String.Equals(value, ViewState["HeaderText"])) { 
                    ViewState["HeaderText"] = value;
                    if (!_suppressHeaderTextFieldChange) { 
                        OnFieldChanged();
                    }
                }
            } 
        }
 
        ///  
        /// Gets or sets a property indicating whether data should be HtmlEncoded when it is displayed to the user.
        ///  
        [
        WebCategory("Behavior"),
        DefaultValue(true),
        WebSysDescription(SR.BoundField_HtmlEncode) 
        ]
        public virtual bool HtmlEncode { 
            get { 
                if (!_htmlEncodeSet) {
                    object o = ViewState["HtmlEncode"]; 
                    if (o != null) {
                        _htmlEncode = (bool)o;
                    }
                    else { 
                        _htmlEncode = true;
                    } 
                    _htmlEncodeSet = true; 
                }
                return _htmlEncode; 
            }
            set {
                object oldValue = ViewState["HtmlEncode"];
                if (oldValue == null || (bool)oldValue != value) { 
                    ViewState["HtmlEncode"] = value;
                    _htmlEncode = value; 
                    _htmlEncodeSet = true; 
                    OnFieldChanged();
                } 
            }
        }

        ///  
        /// Gets or sets a property indicating whether the format string should be HtmlEncoded
        /// when it is displayed to the user. 
        ///  
        [
        WebCategory("Behavior"), 
        DefaultValue(true),
        ]
        public virtual bool HtmlEncodeFormatString {
            get { 
                if (!_htmlEncodeFormatStringSet) {
                    object o = ViewState["HtmlEncodeFormatString"]; 
                    if (o != null) { 
                        _htmlEncodeFormatString = (bool)o;
                    } 
                    else {
                        _htmlEncodeFormatString = true;
                    }
                    _htmlEncodeFormatStringSet = true; 
                }
                return _htmlEncodeFormatString; 
            } 
            set {
                object oldValue = ViewState["HtmlEncodeFormatString"]; 
                if (oldValue == null || (bool)oldValue != value) {
                    ViewState["HtmlEncodeFormatString"] = value;
                    _htmlEncodeFormatString = value;
                    _htmlEncodeFormatStringSet = true; 
                    OnFieldChanged();
                } 
            } 
        }
        ///  
        ///    Gets or sets the property that determines what text is displayed if the value
        ///    of the field is null.
        /// 
        [ 
            WebCategory("Behavior"),
            DefaultValue(""), 
            WebSysDescription(SR.BoundField_NullDisplayText) 
        ]
        public virtual string NullDisplayText { 
            get {
                object o = ViewState["NullDisplayText"];
                if (o != null) {
                    return (string)o; 
                }
                return String.Empty; 
            } 
            set {
                if (!String.Equals(value, ViewState["NullDisplayText"])) { 
                    ViewState["NullDisplayText"] = value;
                    OnFieldChanged();
                }
            } 
        }
 
 
        /// 
        ///    Gets or sets the property that prevents modification to data 
        ///       in this field.
        /// 
        [
            WebCategory("Behavior"), 
            DefaultValue(false),
            WebSysDescription(SR.BoundField_ReadOnly) 
        ] 
        public virtual bool ReadOnly {
            get { 
                object o = ViewState["ReadOnly"];
                if (o != null)
                    return (bool)o;
                return false; 
            }
            set { 
                object oldValue = ViewState["ReadOnly"]; 
                if (oldValue == null || (bool)oldValue != value) {
                    ViewState["ReadOnly"] = value; 
                    OnFieldChanged();
                }
            }
        } 

        protected virtual bool SupportsHtmlEncode { 
            get { 
                return true;
            } 
        }

        protected override void CopyProperties(DataControlField newField) {
            ((BoundField)newField).ApplyFormatInEditMode = ApplyFormatInEditMode; 
            ((BoundField)newField).ConvertEmptyStringToNull = ConvertEmptyStringToNull;
            ((BoundField)newField).DataField = DataField; 
            ((BoundField)newField).DataFormatString = DataFormatString; 
            ((BoundField)newField).HtmlEncode = HtmlEncode;
            ((BoundField)newField).HtmlEncodeFormatString = HtmlEncodeFormatString; 
            ((BoundField)newField).NullDisplayText = NullDisplayText;
            ((BoundField)newField).ReadOnly = ReadOnly;

            base.CopyProperties(newField); 
        }
 
        protected override DataControlField CreateField() { 
            return new BoundField();
        } 


        /// 
        /// Extracts the value(s) from the given cell and puts the value(s) into a dictionary.  Indicate includeReadOnly 
        /// to have readonly fields' values inserted into the dictionary.
        ///  
        public override void ExtractValuesFromCell(IOrderedDictionary dictionary, DataControlFieldCell cell, DataControlRowState rowState, bool includeReadOnly) { 
            Control childControl = null;
            string dataField = DataField; 
            object value = null;
            string nullDisplayText = NullDisplayText;

            if (((rowState & DataControlRowState.Insert) != 0) && !InsertVisible) { 
                return;
            } 
 
            if (cell.Controls.Count > 0) {
                childControl = cell.Controls[0]; 

                TextBox editBox = childControl as TextBox;
                if (editBox != null) {
                    value = editBox.Text; 
                }
            } 
            else { 
                if (includeReadOnly == true) {
                    string cellText = cell.Text; 
                    if (cellText == " ") { // nothing HtmlEncodes to  , so we know that this means it was empty.
                        value = String.Empty;
                    }
                    else { 
                        if (SupportsHtmlEncode && HtmlEncode) {
                            value = HttpUtility.HtmlDecode(cellText); 
                        } 
                        else {
                            value = cellText; 
                        }
                    }
                }
            } 

            if (value != null) { 
                if ((value is string) && (((string)value).Length == 0) && ConvertEmptyStringToNull) { 
                    value = null;
                } 

                if (value is string && (string)value == nullDisplayText && nullDisplayText.Length > 0) {
                    value = null;
                } 

                if (dictionary.Contains(dataField)) { 
                    dictionary[dataField] = value; 
                }
                else { 
                    dictionary.Add(dataField, value);
                }
            }
 
        }
 
 
        /// 
        /// Returns the value of the field formatted as text for the cell. 
        /// 
        protected virtual string FormatDataValue(object dataValue, bool encode) {
            string formattedValue = String.Empty;
 
            if (!DataBinder.IsNull(dataValue)) {
                string dataValueString = dataValue.ToString(); 
                string formatting = DataFormatString; 
                int dataValueStringLength = dataValueString.Length;
 
                if (!HtmlEncodeFormatString) {
                    // Back-compat (Whidbey) behavior when HtmlEncodeFormatString=false
                    if (dataValueStringLength > 0 && encode) {
                        dataValueString = HttpUtility.HtmlEncode(dataValueString); 
                    }
 
                    if (dataValueStringLength == 0 && ConvertEmptyStringToNull) { 
                        formattedValue = NullDisplayText;
                    } 
                    else if (formatting.Length == 0) {
                        formattedValue = dataValueString;
                    }
                    else { 
                        if (encode) {
                            formattedValue = String.Format(CultureInfo.CurrentCulture, formatting, dataValueString); 
                        } 
                        else {
                            formattedValue = String.Format(CultureInfo.CurrentCulture, formatting, dataValue); 
                        }
                    }
                }
                else { 
                    // New default behavior (Orcas) when HtmlEncodeFormatString=true
 
                    // If the result is still empty and ConvertEmptyStringToNull=true, replace the value with the NullDisplayText 
                    if (dataValueStringLength == 0 && ConvertEmptyStringToNull) {
                        dataValueString = NullDisplayText; 
                    }
                    else {
                        // If there's a format string, apply it to the raw data value
                        // If there's no format string, then dataValueString already has the right value 
                        if (!String.IsNullOrEmpty(formatting)) {
                            dataValueString = String.Format(CultureInfo.CurrentCulture, formatting, dataValue); 
                        } 

                        // Optionally HTML encode the value (including the format string, if any was applied) 
                        if (!String.IsNullOrEmpty(dataValueString) && encode) {
                            dataValueString = HttpUtility.HtmlEncode(dataValueString);
                        }
                    } 

                    formattedValue = dataValueString; 
                } 
            }
            else { 
                formattedValue = NullDisplayText;
            }

            return formattedValue; 
        }
 
 
        /// 
        /// Returns a value to be used for design-time rendering 
        /// 
        protected virtual object GetDesignTimeValue() {
            return SR.GetString(SR.Sample_Databound_Text);
        } 

 
        ///  
        /// Retrieves the value of the field to be databound to the BoundField.
        ///  
        protected virtual object GetValue(Control controlContainer) {
            Debug.Assert(DataField.Length != 0, "Shouldn't be DataBinding without a DataField");

            object data = null; 
            object dataItem = null;
            string boundField = DataField; 
 
            if (controlContainer == null) {
                throw new HttpException(SR.GetString(SR.DataControlField_NoContainer)); 
            }

            // Get the DataItem from the container
            dataItem = DataBinder.GetDataItem(controlContainer); 

            if (dataItem == null && !DesignMode) { 
                throw new HttpException(SR.GetString(SR.DataItem_Not_Found)); 
            }
            // Get value of field in data item 
            if (_boundFieldDesc == null) {
                if (!boundField.Equals(ThisExpression)) {
                    _boundFieldDesc = TypeDescriptor.GetProperties(dataItem).Find(boundField, true);
                    if ((_boundFieldDesc == null) && !DesignMode) { 
                        throw new HttpException(SR.GetString(SR.Field_Not_Found, boundField));
                    } 
                } 
            }
 
            if (_boundFieldDesc != null && dataItem != null) {
                data = _boundFieldDesc.GetValue(dataItem);
            }
            else { 
                if (DesignMode) {
                    data = GetDesignTimeValue(); 
                } 
                else {
                    data = dataItem; 
                }
            }

            return data; 
        }
 
 
        /// 
        /// Initializes the field and resets member variables. 
        /// 
        public override bool Initialize(bool enableSorting, Control control) {
            base.Initialize(enableSorting, control);
            _boundFieldDesc = null; 
            return false;
        } 
 

        ///  
        /// Initializes a cell in the DataControlField.
        /// 
        public override void InitializeCell(DataControlFieldCell cell, DataControlCellType cellType, DataControlRowState rowState, int rowIndex) {
            string unencodedHeaderText = null; 
            bool changedHeaderText = false;
            bool encode = false; 
            // if this is a header cell and we're htmlEncoding, htmlEncode the HeaderText before the base class tries to render it 
            if (cellType == DataControlCellType.Header && SupportsHtmlEncode && HtmlEncode) {
                unencodedHeaderText = HeaderText; 
                encode = true;
            }

            if (encode && !String.IsNullOrEmpty(unencodedHeaderText)) { 
                _suppressHeaderTextFieldChange = true;
                HeaderText = HttpUtility.HtmlEncode(unencodedHeaderText); 
                changedHeaderText = true; 
            }
            base.InitializeCell(cell, cellType, rowState, rowIndex); 

            // restore the HeaderText property
            if (changedHeaderText) {
                HeaderText = unencodedHeaderText; 
                _suppressHeaderTextFieldChange = false;
            } 
            switch (cellType) { 
                case DataControlCellType.DataCell:
                    InitializeDataCell(cell, rowState); 
                    break;
            }
        }
 

        protected virtual void InitializeDataCell(DataControlFieldCell cell, DataControlRowState rowState) { 
            Control childControl = null; 
            Control boundControl = null;
 
            if (((rowState & DataControlRowState.Edit) != 0 && ReadOnly == false) || (rowState & DataControlRowState.Insert) != 0) {
                //
                TextBox editor = new TextBox();
                editor.ToolTip = HeaderText; 
                childControl = editor;
 
                if (DataField.Length != 0 && (rowState & DataControlRowState.Edit) != 0) { 
                    boundControl = editor;
                } 
            }
            else if (DataField.Length != 0) {
                boundControl = cell;
            } 

            if (childControl != null) { 
                cell.Controls.Add(childControl); 
            }
 
            if (boundControl != null && Visible) {
                boundControl.DataBinding += new EventHandler(this.OnDataBindField);
            }
        } 

 
        ///  
        /// 
        protected virtual void OnDataBindField(object sender, EventArgs e) { 
            Control boundControl = (Control)sender;
            Control controlContainer = boundControl.NamingContainer;

            object data = GetValue(controlContainer); 
            bool encodeValue = SupportsHtmlEncode && HtmlEncode && boundControl is TableCell;
            string dataValue = FormatDataValue(data, encodeValue); 
 
            if (boundControl is TableCell) {
                if (dataValue.Length == 0) { 
                    dataValue = " ";
                }
                ((TableCell)boundControl).Text = dataValue;
            } 
            else {
                if (!(boundControl is TextBox)) { 
                    throw new HttpException(SR.GetString(SR.BoundField_WrongControlType, DataField)); 
                }
 
                if (ApplyFormatInEditMode) {
                    ((TextBox)boundControl).Text = dataValue;
                }
                else { 
                    if (data != null) {
                        ((TextBox)boundControl).Text = data.ToString(); 
                    } 
                }
 
                if (data != null) {
                    // size down the textbox for certain types
                    if (data.GetType().IsPrimitive) {
                        ((TextBox)boundControl).Columns = 5; 
                    }
                } 
            } 
        }
 
        protected override void LoadViewState(object state) {
             // DevDiv Bugs 188902: Clear cached values as they may be stale after ViewState loads.
             _dataField = null;
             _dataFormatString = null; 
             _htmlEncodeSet = false;
             _htmlEncodeFormatStringSet = false; 
 
             base.LoadViewState(state);
        } 

        /// 
        /// Override with an empty body if the field's controls all support callback.
        ///  Otherwise, override and throw a useful error message about why the field can't support callbacks. 
        /// 
        public override void ValidateSupportsCallback() { 
        } 
    }
} 


// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
                        

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