DataTrigger.cs source code in C# .NET

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Code:

/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Framework / System / Windows / DataTrigger.cs / 1305600 / DataTrigger.cs

                            //---------------------------------------------------------------------------- 
//
// 
//    Copyright (C) Microsoft Corporation.  All rights reserved.
//  
//
// Description: Defines DataTrigger object, akin to Trigger except it 
//              gets values from data. 
//
//--------------------------------------------------------------------------- 

using System;
using System.Collections.Specialized;
using System.ComponentModel; 
using System.Diagnostics;
using System.Windows.Data; 
using System.Windows.Markup; 

namespace System.Windows 
{
    /// 
    ///     A single Style data conditional dependency driver
    ///  
    [ContentProperty("Setters")]
    [XamlSetMarkupExtensionAttribute("ReceiveMarkupExtension")] 
    public class DataTrigger : TriggerBase, IAddChild 
    {
        ///  
        ///     Binding declaration of the conditional
        /// 
        [Localizability(LocalizationCategory.None, Readability = Readability.Unreadable)] // Not localizable by-default
        public BindingBase Binding 
        {
            get 
            { 
                // Verify Context Access
                VerifyAccess(); 

                return _binding;
            }
            set 
            {
                // Verify Context Access 
                VerifyAccess(); 

                if (IsSealed) 
                {
                    throw new InvalidOperationException(SR.Get(SRID.CannotChangeAfterSealed, "DataTrigger"));
                }
 
                _binding = value;
            } 
        } 

        ///  
        ///     Value of the condition (equality check)
        /// 
        [DependsOn("Binding")]
        [Localizability(LocalizationCategory.None, Readability = Readability.Unreadable)] // Not localizable by-default 
        public object Value
        { 
            get 
            {
                // Verify Context Access 
                VerifyAccess();

                return _value;
            } 
            set
            { 
                // Verify Context Access 
                VerifyAccess();
 
                if (IsSealed)
                {
                    throw new InvalidOperationException(SR.Get(SRID.CannotChangeAfterSealed, "DataTrigger"));
                } 

                if (value is MarkupExtension) 
                { 
                    throw new ArgumentException(SR.Get(SRID.ConditionValueOfMarkupExtensionNotSupported,
                                                       value.GetType().Name)); 
                }

                if( value is Expression )
                { 
                    throw new ArgumentException(SR.Get(SRID.ConditionValueOfExpressionNotSupported));
                } 
 
                _value = value;
            } 
        }

        /// 
        ///     Collection of Setter objects, which describes what to apply 
        /// when this trigger is active.
        ///  
        [DesignerSerializationVisibility(DesignerSerializationVisibility.Content)] 
        public SetterBaseCollection Setters
        { 
            get
            {
                // Verify Context Access
                VerifyAccess(); 

                if( _setters == null ) 
                { 
                    _setters = new SetterBaseCollection();
                } 
                return _setters;
            }
        }
 
        ///
        /// This method is called to Add a Setter object as a child of the Style. 
        /// 
        ///
        /// The object to add as a child; it must be a Setter or subclass. 
        ///
        void IAddChild.AddChild (Object value)
        {
            // Verify Context Access 
            VerifyAccess();
 
            Setters.Add(Trigger.CheckChildIsSetter(value)); 
        }
 
        ///
        /// This method is called by the parser when text appears under the tag in markup.
        /// As default Styles do not support text, calling this method has no effect.
        /// 
        ///
        /// Text to add as a child. 
        /// 
        void IAddChild.AddText (string text)
        { 
            // Verify Context Access
            VerifyAccess();

            XamlSerializerUtil.ThrowIfNonWhiteSpaceInAddText(text, this); 
        }
 
        internal sealed override void Seal() 
        {
            if (IsSealed) 
            {
                return;
            }
 
            // Process the _setters collection: Copy values into PropertyValueList and seal the Setter objects.
            ProcessSettersCollection(_setters); 
 
            // Freeze the value for the trigger
            StyleHelper.SealIfSealable(_value); 

            // Build conditions array from collection
            TriggerConditions = new TriggerCondition[] {
                new TriggerCondition( 
                    _binding,
                    LogicalOp.Equals, 
                    _value) }; 

            // Set Condition for all data triggers 
            for (int i = 0; i < PropertyValues.Count; i++)
            {
                PropertyValue propertyValue = PropertyValues[i];
 
                propertyValue.Conditions = TriggerConditions;
                switch (propertyValue.ValueType) 
                { 
                    case PropertyValueType.Trigger:
                        propertyValue.ValueType = PropertyValueType.DataTrigger; 
                        break;
                    case PropertyValueType.PropertyTriggerResource:
                        propertyValue.ValueType = PropertyValueType.DataTriggerResource;
                        break; 
                    default:
                        throw new InvalidOperationException(SR.Get(SRID.UnexpectedValueTypeForDataTrigger, propertyValue.ValueType)); 
                } 

                // Put back modified struct 
                PropertyValues[i] = propertyValue;
            }

            base.Seal(); 
        }
 
        // evaluate the current state of the trigger 
        internal override bool GetCurrentState(DependencyObject container, UncommonField dataField)
        { 
            Debug.Assert( TriggerConditions != null && TriggerConditions.Length == 1,
                "This method assumes there is exactly one TriggerCondition." );

            return TriggerConditions[0].ConvertAndMatch(StyleHelper.GetDataTriggerValue(dataField, container, TriggerConditions[0].Binding)); 
        }
 
        private BindingBase _binding; 
        private object _value = DependencyProperty.UnsetValue;
        private SetterBaseCollection _setters = null; 

        public static void ReceiveMarkupExtension(object targetObject, XamlSetMarkupExtensionEventArgs eventArgs)
        {
            if (targetObject == null) 
            {
                throw new ArgumentNullException("targetObject"); 
            } 
            if (eventArgs == null)
            { 
                throw new ArgumentNullException("eventArgs");
            }

            DataTrigger trigger = targetObject as DataTrigger; 
            if (trigger != null && eventArgs.Member.Name == "Binding" && eventArgs.MarkupExtension is BindingBase)
            { 
                trigger.Binding = eventArgs.MarkupExtension as BindingBase; 

                eventArgs.Handled = true; 
            }
            else
            {
                eventArgs.CallBase(); 
            }
        } 
    } 
}
 


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

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