Code:
/ DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Framework / System / Windows / Data / RelativeSource.cs / 1 / RelativeSource.cs
//---------------------------------------------------------------------------- // //// Copyright (C) Microsoft Corporation. All rights reserved. // // // Description: Defines RelativeSource MarkupExtension. // //--------------------------------------------------------------------------- using System.ComponentModel; // ISupportInitialize using System.Diagnostics; using System.Windows.Markup; // MarkupExtension namespace System.Windows.Data { ///This enum describes the type of RelativeSource /// public enum RelativeSourceMode { ///use the DataContext from the previous scope /// PreviousData, ///use the target element's styled parent /// TemplatedParent, ///use the target element itself /// Self, ///use the target element's ancestor of a specified Type /// FindAncestor } ////// /// RelativeSource Modes are /// PreviousData - use the DataContext from the previous scope /// TemplatedParent- use the target element's styled parent /// Self - use the target element itself /// FindAncestor - use the hosting Type /// Only FindAncestor mode allows AncestorType and AncestorLevel. /// [MarkupExtensionReturnType(typeof(RelativeSource))] public class RelativeSource : MarkupExtension, ISupportInitialize { #region constructors ///Constructor /// public RelativeSource() { // default mode to FindAncestor so that setting Type and Level would be OK _mode = RelativeSourceMode.FindAncestor; } ///Constructor /// public RelativeSource(RelativeSourceMode mode) { InitializeMode(mode); } ///Constructor for FindAncestor mode /// public RelativeSource(RelativeSourceMode mode, Type ancestorType, int ancestorLevel) { InitializeMode(mode); AncestorType = ancestorType; AncestorLevel = ancestorLevel; } #endregion constructors #region ISupportInitialize ///Begin Initialization void ISupportInitialize.BeginInit() { } ///End Initialization, verify that internal state is consistent void ISupportInitialize.EndInit() { if (IsUninitialized) throw new InvalidOperationException(SR.Get(SRID.RelativeSourceNeedsMode)); if (_mode == RelativeSourceMode.FindAncestor && (AncestorType == null)) throw new InvalidOperationException(SR.Get(SRID.RelativeSourceNeedsAncestorType)); } #endregion ISupportInitialize #region public properties ///static instance of RelativeSource for PreviousData mode. /// public static RelativeSource PreviousData { get { if (s_previousData == null) { s_previousData = new RelativeSource(RelativeSourceMode.PreviousData); } return s_previousData; } } ///static instance of RelativeSource for TemplatedParent mode. /// public static RelativeSource TemplatedParent { get { if (s_templatedParent == null) { s_templatedParent = new RelativeSource(RelativeSourceMode.TemplatedParent); } return s_templatedParent; } } ///static instance of RelativeSource for Self mode. /// public static RelativeSource Self { get { if (s_self == null) { s_self = new RelativeSource(RelativeSourceMode.Self); } return s_self; } } ///mode of RelativeSource /// ///Mode is read-only after initialization. /// If Mode is not set explicitly, setting AncestorType or AncestorLevel will implicitly lock the Mode to FindAncestor. ///RelativeSource Mode is immutable after initialization; /// instead of changing the Mode on this instance, create a new RelativeSource or use a different static instance. [ConstructorArgument("mode")] public RelativeSourceMode Mode { get { return _mode; } set { if (IsUninitialized) { InitializeMode(value); } else if (value != _mode) // mode changes are not allowed { throw new InvalidOperationException(SR.Get(SRID.RelativeSourceModeIsImmutable)); } } } ///The Type of ancestor to look for, in FindAncestor mode. /// ///if Mode has not been set explicitly, setting AncestorType will implicitly lock Mode to FindAncestor. ///RelativeSource is not in FindAncestor mode public Type AncestorType { get { return _ancestorType; } set { if (IsUninitialized) { Debug.Assert(_mode == RelativeSourceMode.FindAncestor); AncestorLevel = 1; // lock the mode and set default level } if (_mode != RelativeSourceMode.FindAncestor) { // in all other modes, AncestorType should not get set to a non-null value if (value != null) throw new InvalidOperationException(SR.Get(SRID.RelativeSourceNotInFindAncestorMode)); } else { _ancestorType = value; } } } ////// This method is used by TypeDescriptor to determine if this property should /// be serialized. /// [EditorBrowsable(EditorBrowsableState.Never)] public bool ShouldSerializeAncestorType() { return (_mode == RelativeSourceMode.FindAncestor); } ///The level of ancestor to look for, in FindAncestor mode. Use 1 to indicate the one nearest to the target element. /// ///if Mode has not been set explicitly, getting AncestorLevel will return -1 and /// setting AncestorLevel will implicitly lock Mode to FindAncestor. ///RelativeSource is not in FindAncestor mode ///AncestorLevel cannot be set to less than 1 public int AncestorLevel { get { return _ancestorLevel; } set { Debug.Assert((!IsUninitialized) || (_mode == RelativeSourceMode.FindAncestor)); if (_mode != RelativeSourceMode.FindAncestor) { // in all other modes, AncestorLevel should not get set to a non-zero value if (value != 0) throw new InvalidOperationException(SR.Get(SRID.RelativeSourceNotInFindAncestorMode)); } else if (value < 1) { throw new ArgumentOutOfRangeException(SR.Get(SRID.RelativeSourceInvalidAncestorLevel)); } else { _ancestorLevel = value; } } } ////// This method is used by TypeDescriptor to determine if this property should /// be serialized. /// [EditorBrowsable(EditorBrowsableState.Never)] public bool ShouldSerializeAncestorLevel() { return (_mode == RelativeSourceMode.FindAncestor); } #endregion public properties #region public methods ////// Return an object that should be set on the targetObject's targetProperty /// for this markup extension. /// /// ServiceProvider that can be queried for services. ////// The object to set on this property. /// public override object ProvideValue(IServiceProvider serviceProvider) { if (_mode == RelativeSourceMode.PreviousData) return PreviousData; if (_mode == RelativeSourceMode.Self) return Self; if (_mode == RelativeSourceMode.TemplatedParent) return TemplatedParent; return this; } #endregion public methods #region private properties private bool IsUninitialized { get { return (_ancestorLevel == -1); } } #endregion private properties #region private methods void InitializeMode(RelativeSourceMode mode) { Debug.Assert(IsUninitialized); if (mode == RelativeSourceMode.FindAncestor) { // default level _ancestorLevel = 1; _mode = mode; } else if (mode == RelativeSourceMode.PreviousData || mode == RelativeSourceMode.Self || mode == RelativeSourceMode.TemplatedParent) { _ancestorLevel = 0; _mode = mode; } else { throw new ArgumentException(SR.Get(SRID.RelativeSourceModeInvalid), "mode"); } } #endregion private methods #region private fields private RelativeSourceMode _mode; private Type _ancestorType; private int _ancestorLevel = -1; // while -1, indicates _mode has not been set private static RelativeSource s_previousData; private static RelativeSource s_templatedParent; private static RelativeSource s_self; #endregion private fields } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. 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