DataObjectPastingEventArgs.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Core / System / Windows / DataObjectPastingEventArgs.cs / 1 / DataObjectPastingEventArgs.cs
                        

                        
                            //---------------------------------------------------------------------------- 
//
// 
//    Copyright (C) Microsoft Corporation.  All rights reserved.
//  
//
// Description: DataObject.Pasting event arguments 
// 
//---------------------------------------------------------------------------
 
using System;

using SR=MS.Internal.PresentationCore.SR;
using SRID=MS.Internal.PresentationCore.SRID; 

namespace System.Windows 
{ 
    /// 
    /// Arguments for the DataObject.Pasting event. 
    ///
    /// The DataObject.Pasting event is raising when an editor
    /// has inspected all formats available on a data object
    /// has choosen one of them as the most suitable and 
    /// is ready for pasting it into a current selection.
    /// An application can inspect a DataObject, change, remove or 
    /// add some data formats into it and decide whether to proceed 
    /// with the pasting or cancel it.
    ///  
    public sealed class DataObjectPastingEventArgs : DataObjectEventArgs
    {
        //-----------------------------------------------------
        // 
        //  Constructors
        // 
        //----------------------------------------------------- 

        #region Constructors 

        /// 
        /// Creates a DataObjectPastingEvent.
        /// This object created by editors executing a Copy/Paste 
        /// and Drag/Drop comands.
        ///  
        ///  
        /// DataObject extracted from the Clipboard and intended
        /// for using in pasting. 
        /// 
        /// 
        /// A flag indicating whether this operation is part of drag/drop.
        /// Pasting event is fired on drop. 
        /// 
        ///  
        /// String identifying a format an editor has choosen 
        /// as a candidate for applying in Paste operation.
        /// An application can change this choice after inspecting 
        /// the content of data object.
        /// 
        public DataObjectPastingEventArgs(IDataObject dataObject, bool isDragDrop, string formatToApply) //
            : base(System.Windows.DataObject.PastingEvent, isDragDrop) 
        {
            if (dataObject == null) 
            { 
                throw new ArgumentNullException("dataObject");
            } 

            if (formatToApply == null)
            {
                throw new ArgumentNullException("formatToApply"); 
            }
 
            if (formatToApply == string.Empty) 
            {
                throw new ArgumentException(SR.Get(SRID.DataObject_EmptyFormatNotAllowed)); 
            }

            if (!dataObject.GetDataPresent(formatToApply))
            { 
                throw new ArgumentException(SR.Get(SRID.DataObject_DataFormatNotPresentOnDataObject, formatToApply));
            } 
 
            _originalDataObject = dataObject;
            _dataObject = dataObject; 
            _formatToApply = formatToApply;
        }

        #endregion Constructors 

        //------------------------------------------------------ 
        // 
        //  Public Properties
        // 
        //-----------------------------------------------------

        #region Public Properties
 
        /// 
        /// DataObject original extracted from the Clipboard. 
        /// It's content cannot be changed to avoid side effects 
        /// on subsequent paste operations in this or other
        /// applications. 
        /// To change the content of a data object custon handler
        /// must create new instance of an object and assign it
        /// to DataObject property, which will be used by
        /// an editor to perform a paste operation. 
        /// Initially both properties DataObject and SourceDataObject
        /// have the same value. DataObject property can be changed 
        /// by a custom handler, SourceDataObject keeps original value. 
        /// SourceDataObject can be useful in a case when several
        /// independent DataObjectPastingEventHandlers workone after onother. 
        /// After one handler added its new DataObject SourceDataObject
        /// property allows other handlers to access original clipboard.
        /// 
        public IDataObject SourceDataObject 
        {
            get 
            { 
                return _originalDataObject;
            } 
        }

        /// 
        /// DataObject suggested for a pasting operation. 
        /// Originally this property has the same value as SourceDataObject.
        /// Custom handlers can change it by assigning some new dataobject. 
        /// This new dataobject must have at least one format set to it, 
        /// which will become a suggested format (FormatToAppy) when
        /// dataobject is assigned. Thus FormatToAlly is always consistent 
        /// with current DataObject (but not necessarily with SourceDataObject).
        /// 
        public IDataObject DataObject
        { 
            get
            { 
                return _dataObject; 
            }
 
            set
            {
                string[] availableFormats;
 
                if (value == null)
                { 
                    throw new ArgumentNullException("value"); 
                }
 
                availableFormats = value.GetFormats(/*autoConvert:*/false);
                if (availableFormats == null || availableFormats.Length == 0)
                {
                    throw new ArgumentException(SR.Get(SRID.DataObject_DataObjectMustHaveAtLeastOneFormat)); 
                }
 
                _dataObject = value; 
                _formatToApply = availableFormats[0];
            } 
        }

        /// 
        /// String identifying a format an editor has choosen 
        /// as a candidate for applying in Paste operation.
        /// An application can change this choice after inspecting 
        /// the content of data object. 
        /// The value assigned to FormatToApply must be present
        /// on a current DataObject. The invariant is 
        /// this.DataObject.GetDataPresent(this.FormatToApply) === true.
        /// 
        public string FormatToApply
        { 
            get
            { 
                return _formatToApply; 
            }
            set 
            {
                if (value == null)
                {
                    throw new ArgumentNullException("value"); 
                }
 
                if (!_dataObject.GetDataPresent(value)) 
                {
                    throw new ArgumentException(SR.Get(SRID.DataObject_DataFormatNotPresentOnDataObject, value)); 
                }

                _formatToApply = value;
            } 
        }
 
        #endregion Public Properties 

        #region Protected Methods 

        //------------------------------------------------------
        //
        //  Protected Methods 
        //
        //------------------------------------------------------ 
 
        /// 
        /// The mechanism used to call the type-specific handler on the target. 
        /// 
        /// 
        /// The generic handler to call in a type-specific way.
        ///  
        /// 
        /// The target to call the handler on. 
        ///  
        protected override void InvokeEventHandler(Delegate genericHandler, object genericTarget)
        { 
            DataObjectPastingEventHandler handler = (DataObjectPastingEventHandler)genericHandler;
            handler(genericTarget, this);
        }
 
        #endregion Protected Methods
 
        //----------------------------------------------------- 
        //
        //  Private Fields 
        //
        //------------------------------------------------------

        #region Private Fields 

        private IDataObject _originalDataObject; 
 
        private IDataObject _dataObject;
 
        private string _formatToApply;

        #endregion Private Fields
    } 

    ///  
    /// The delegate to use for handlers that receive the DataObject.Pasting event. 
    /// 
    ///  
    /// An event handler for a DataObject.Pasting event.
    /// It is called when ah editor already made a decision
    /// what format (from available on the Cliipboard)
    /// to apply to selection. With this handler an application 
    /// has a chance to inspect a content of DataObject extracted
    /// from the Clipboard and decide what format to use instead. 
    /// There are four options for the handler here: 
    /// a) to cancel the whole Paste/Drop event by calling
    /// DataObjectPastingEventArgs.CancelCommand method, 
    /// b) change an editor's choice of format by setting
    /// new value for DataObjectPastingEventArgs.FormatToApply
    /// property (the new value is supposed to be understandable
    /// by an editor - it's application's code responsibility 
    /// to act consistently with an editor; example is to
    /// replace "rich text" (xml) format to "plain text" format - 
    /// both understandable by the TextEditor). 
    /// c) choose it's own custom format, apply it to a selection
    /// and cancel a command for the following execution in an 
    /// editor by calling DataObjectPastingEventArgs.CancelCommand
    /// method. This is how custom data formats are expected
    /// to be pasted.
    /// d) create new piece of data and suggest it in a new instance 
    /// of DataObject. newDataObject instance must be created
    /// with some format set to it and assigned to DataObject property. 
    /// SourceDataObject property keeps an original DataObject 
    /// came from the Clipboard. This original dataobject cannot be changed.
    /// So by assigning new dataobject a custom handler can suggest 
    /// ned data formats or change existing dataformats.
    /// 
    public delegate void DataObjectPastingEventHandler(object sender, DataObjectPastingEventArgs e);
} 

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

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