TextElementEnumerator.cs source code in C# .NET

Source code for the .NET framework in C#

                        

Code:

/ 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Framework / System / Windows / Documents / TextElementEnumerator.cs / 1305600 / TextElementEnumerator.cs

                            //---------------------------------------------------------------------------- 
//
// 
//    Copyright (C) Microsoft Corporation.  All rights reserved.
//  
//
// 
// Description: IEnumerator for TextRange and TextElement content. 
//
// 
// History:
//  05/27/2003 : [....] - Created
//
//--------------------------------------------------------------------------- 

using System; 
using System.Collections; 
using System.Collections.Generic;
using MS.Internal; 
using System.Text;
using MS.Utility;
using System.Windows.Controls;
 
#pragma warning disable 1634, 1691  // suppressing PreSharp warnings
 
namespace System.Windows.Documents 
{
    internal class TextElementEnumerator : IEnumerator where TextElementType : TextElement 
    {
        //-----------------------------------------------------
        //
        //  Constructors 
        //
        //----------------------------------------------------- 
 
        #region Constructors
 
        // Creates an enumerator instance.
        // Null start/end creates an empty enumerator.
        internal TextElementEnumerator(TextPointer start, TextPointer end)
        { 
            Invariant.Assert(start != null && end != null || start == null && end == null, "If start is null end should be null!");
 
            _start = start; 
            _end = end;
 
            // Remember what generation the backing store was in when we started,
            // so we can throw if this enumerator is accessed after content has
            // changed.
            if (_start != null) 
            {
                _generation = _start.TextContainer.Generation; 
            } 
        }
 
        #endregion Constructors

        //------------------------------------------------------
        // 
        //  Public Methods
        // 
        //----------------------------------------------------- 

        #region Public Methods 

        public void Dispose()
        {
            // Empty the enumerator 
            _current = null;
            _navigator = null; 
            GC.SuppressFinalize(this); 
        }
 
        object System.Collections.IEnumerator.Current
        {
            get
            { 
                return this.Current;
            } 
        } 

        ///  
        /// Return the current object this enumerator is pointing to.  This is
        /// generally a FrameworkElement, TextElement, an embedded
        /// object, or Text content.
        ///  
        /// 
        /// According to the IEnumerator spec, the Current property keeps 
        /// the element even after the content has been modified 
        /// (even if the current element has been deleted from the collection).
        /// This is unlike to Reset or MoveNext which throw after any content change. 
        /// 
        public TextElementType Current
        {
            get 
            {
                if (_navigator == null) 
                { 
                    #pragma warning suppress 6503 // IEnumerator.Current is documented to throw this exception
                    throw new InvalidOperationException(SR.Get(SRID.EnumeratorNotStarted)); 
                }

                if (_current == null)
                { 
                    #pragma warning suppress 6503 // IEnumerator.Current is documented to throw this exception
                    throw new InvalidOperationException(SR.Get(SRID.EnumeratorReachedEnd)); 
                } 

                return _current; 
            }
        }

        ///  
        /// Advance the enumerator to the next object in the range.  Return true if content
        /// was found. 
        ///  
        public bool MoveNext()
        { 
            // Throw if the tree has been modified since this enumerator was created.
            if (_start != null && _generation != _start.TextContainer.Generation)
            {
                throw new InvalidOperationException(SR.Get(SRID.EnumeratorVersionChanged)); 
            }
 
            // Return false if the collection is empty 
            if (_start == null || _start.CompareTo(_end) == 0)
            { 
                return false;
            }

            // Return false if the navigator reached the end of the collection 
            if (_navigator != null && _navigator.CompareTo(_end) >= 0)
            { 
                return false; 
            }
 
            // Advance the navigator
            if (_navigator == null)
            {
                // Set it to the first element for the very first move 
                _navigator = new TextPointer(_start);
                _navigator.MoveToNextContextPosition(LogicalDirection.Forward); 
            } 
            else
            { 
                // Move to the next element in the collection
                Invariant.Assert(_navigator.GetPointerContext(LogicalDirection.Backward) == TextPointerContext.ElementStart,
                    "Unexpected run type in TextElementEnumerator");
 
                _navigator.MoveToElementEdge(ElementEdge.AfterEnd);
                _navigator.MoveToNextContextPosition(LogicalDirection.Forward); 
            } 

            // Update current cache 
            if (_navigator.CompareTo(_end) < 0)
            {
                _current = (TextElementType)_navigator.Parent;
            } 
            else
            { 
                _current = null; 
            }
 
            // Return true if the content was found
            return (_current != null);
        }
 
        /// 
        /// Reset the enumerator to the start of the range. 
        ///  
        public void Reset()
        { 
            // Throw if the tree has been modified since this enumerator was created.
            if (_start != null && _generation != _start.TextContainer.Generation)
            {
                throw new InvalidOperationException(SR.Get(SRID.EnumeratorVersionChanged)); 
            }
 
            _navigator = null; 
            _current = null;
        } 

        #endregion Public Methods

        //------------------------------------------------------ 
        //
        //  Public Properties 
        // 
        //------------------------------------------------------
 
        #region Public Properties

        #endregion Public Properties
 
        //-----------------------------------------------------
        // 
        //  Public Events 
        //
        //------------------------------------------------------ 

        #region Public Events

        #endregion Public Events 

        //----------------------------------------------------- 
        // 
        //  Protected Methods
        // 
        //-----------------------------------------------------

        #region Protected Methods
 
        #endregion Protected Events
 
        //----------------------------------------------------- 
        //
        //  Internal Methods 
        //
        //------------------------------------------------------

        #region Internal Methods 

        #endregion Internal methods 
 
        //-----------------------------------------------------
        // 
        //  Internal Properties
        //
        //------------------------------------------------------
 
        #region Internal Properties
 
        #endregion Internal Properties 

        //------------------------------------------------------ 
        //
        //  Internal Events
        //
        //----------------------------------------------------- 

        #region Internal Events 
 
        #endregion Internal Events
 
        //------------------------------------------------------
        //
        //  Private Properties
        // 
        //-----------------------------------------------------
 
        #region Private Properties 

        #endregion Private Properties 

        //-----------------------------------------------------
        //
        //  Private Fields 
        //
        //----------------------------------------------------- 
 
        #region Private Fields
 
        // Edges of the span to enumerator over.
        private readonly TextPointer _start;
        private readonly TextPointer _end;
 
        // Backing store generation when this enumerator was created.
        private readonly uint _generation; 
 
        // Current position in the enumeration.
        private TextPointer _navigator; 

        // Calculated content at the current position.
        private TextElementType _current;
 
        #endregion Private Fields
    } 
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
//---------------------------------------------------------------------------- 
//
// 
//    Copyright (C) Microsoft Corporation.  All rights reserved.
//  
//
// 
// Description: IEnumerator for TextRange and TextElement content. 
//
// 
// History:
//  05/27/2003 : [....] - Created
//
//--------------------------------------------------------------------------- 

using System; 
using System.Collections; 
using System.Collections.Generic;
using MS.Internal; 
using System.Text;
using MS.Utility;
using System.Windows.Controls;
 
#pragma warning disable 1634, 1691  // suppressing PreSharp warnings
 
namespace System.Windows.Documents 
{
    internal class TextElementEnumerator : IEnumerator where TextElementType : TextElement 
    {
        //-----------------------------------------------------
        //
        //  Constructors 
        //
        //----------------------------------------------------- 
 
        #region Constructors
 
        // Creates an enumerator instance.
        // Null start/end creates an empty enumerator.
        internal TextElementEnumerator(TextPointer start, TextPointer end)
        { 
            Invariant.Assert(start != null && end != null || start == null && end == null, "If start is null end should be null!");
 
            _start = start; 
            _end = end;
 
            // Remember what generation the backing store was in when we started,
            // so we can throw if this enumerator is accessed after content has
            // changed.
            if (_start != null) 
            {
                _generation = _start.TextContainer.Generation; 
            } 
        }
 
        #endregion Constructors

        //------------------------------------------------------
        // 
        //  Public Methods
        // 
        //----------------------------------------------------- 

        #region Public Methods 

        public void Dispose()
        {
            // Empty the enumerator 
            _current = null;
            _navigator = null; 
            GC.SuppressFinalize(this); 
        }
 
        object System.Collections.IEnumerator.Current
        {
            get
            { 
                return this.Current;
            } 
        } 

        ///  
        /// Return the current object this enumerator is pointing to.  This is
        /// generally a FrameworkElement, TextElement, an embedded
        /// object, or Text content.
        ///  
        /// 
        /// According to the IEnumerator spec, the Current property keeps 
        /// the element even after the content has been modified 
        /// (even if the current element has been deleted from the collection).
        /// This is unlike to Reset or MoveNext which throw after any content change. 
        /// 
        public TextElementType Current
        {
            get 
            {
                if (_navigator == null) 
                { 
                    #pragma warning suppress 6503 // IEnumerator.Current is documented to throw this exception
                    throw new InvalidOperationException(SR.Get(SRID.EnumeratorNotStarted)); 
                }

                if (_current == null)
                { 
                    #pragma warning suppress 6503 // IEnumerator.Current is documented to throw this exception
                    throw new InvalidOperationException(SR.Get(SRID.EnumeratorReachedEnd)); 
                } 

                return _current; 
            }
        }

        ///  
        /// Advance the enumerator to the next object in the range.  Return true if content
        /// was found. 
        ///  
        public bool MoveNext()
        { 
            // Throw if the tree has been modified since this enumerator was created.
            if (_start != null && _generation != _start.TextContainer.Generation)
            {
                throw new InvalidOperationException(SR.Get(SRID.EnumeratorVersionChanged)); 
            }
 
            // Return false if the collection is empty 
            if (_start == null || _start.CompareTo(_end) == 0)
            { 
                return false;
            }

            // Return false if the navigator reached the end of the collection 
            if (_navigator != null && _navigator.CompareTo(_end) >= 0)
            { 
                return false; 
            }
 
            // Advance the navigator
            if (_navigator == null)
            {
                // Set it to the first element for the very first move 
                _navigator = new TextPointer(_start);
                _navigator.MoveToNextContextPosition(LogicalDirection.Forward); 
            } 
            else
            { 
                // Move to the next element in the collection
                Invariant.Assert(_navigator.GetPointerContext(LogicalDirection.Backward) == TextPointerContext.ElementStart,
                    "Unexpected run type in TextElementEnumerator");
 
                _navigator.MoveToElementEdge(ElementEdge.AfterEnd);
                _navigator.MoveToNextContextPosition(LogicalDirection.Forward); 
            } 

            // Update current cache 
            if (_navigator.CompareTo(_end) < 0)
            {
                _current = (TextElementType)_navigator.Parent;
            } 
            else
            { 
                _current = null; 
            }
 
            // Return true if the content was found
            return (_current != null);
        }
 
        /// 
        /// Reset the enumerator to the start of the range. 
        ///  
        public void Reset()
        { 
            // Throw if the tree has been modified since this enumerator was created.
            if (_start != null && _generation != _start.TextContainer.Generation)
            {
                throw new InvalidOperationException(SR.Get(SRID.EnumeratorVersionChanged)); 
            }
 
            _navigator = null; 
            _current = null;
        } 

        #endregion Public Methods

        //------------------------------------------------------ 
        //
        //  Public Properties 
        // 
        //------------------------------------------------------
 
        #region Public Properties

        #endregion Public Properties
 
        //-----------------------------------------------------
        // 
        //  Public Events 
        //
        //------------------------------------------------------ 

        #region Public Events

        #endregion Public Events 

        //----------------------------------------------------- 
        // 
        //  Protected Methods
        // 
        //-----------------------------------------------------

        #region Protected Methods
 
        #endregion Protected Events
 
        //----------------------------------------------------- 
        //
        //  Internal Methods 
        //
        //------------------------------------------------------

        #region Internal Methods 

        #endregion Internal methods 
 
        //-----------------------------------------------------
        // 
        //  Internal Properties
        //
        //------------------------------------------------------
 
        #region Internal Properties
 
        #endregion Internal Properties 

        //------------------------------------------------------ 
        //
        //  Internal Events
        //
        //----------------------------------------------------- 

        #region Internal Events 
 
        #endregion Internal Events
 
        //------------------------------------------------------
        //
        //  Private Properties
        // 
        //-----------------------------------------------------
 
        #region Private Properties 

        #endregion Private Properties 

        //-----------------------------------------------------
        //
        //  Private Fields 
        //
        //----------------------------------------------------- 
 
        #region Private Fields
 
        // Edges of the span to enumerator over.
        private readonly TextPointer _start;
        private readonly TextPointer _end;
 
        // Backing store generation when this enumerator was created.
        private readonly uint _generation; 
 
        // Current position in the enumeration.
        private TextPointer _navigator; 

        // Calculated content at the current position.
        private TextElementType _current;
 
        #endregion Private Fields
    } 
} 

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

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