DragEventArgs.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Core / CSharp / System / Windows / DragEventArgs.cs / 1305600 / DragEventArgs.cs
                        
                        
                            //---------------------------------------------------------------------------- 
//
// File: DragEventArgs.cs
//
// Copyright (C) Microsoft Corporation.  All rights reserved. 
//
// Description: DragEventArgs for drag-and-drop operation. 
// 
//
// History: 
//  08/19/2004 : sangilj    Created
//
//---------------------------------------------------------------------------
 
using System;
using System.Diagnostics; 
using System.Windows.Media; 
using System.Windows.Input;
 
using SR=MS.Internal.PresentationCore.SR;
using SRID=MS.Internal.PresentationCore.SRID;

namespace System.Windows 
{
    ///  
    /// The DragEventArgs class represents a type of RoutedEventArgs that 
    /// are relevant to all drag events(DragEnter/DragOver/DragLeave/DragDrop).
    ///  
    public sealed class DragEventArgs : RoutedEventArgs
    {
        //-----------------------------------------------------
        // 
        //  Constructors
        // 
        //----------------------------------------------------- 

        #region Constructors 

        /// 
        /// Constructs a DragEventArgs instance.
        ///  
        /// 
        /// The data object used in this drag drop operation. 
        ///  
        /// 
        /// The current state of the mouse button and modifier keys. 
        /// 
        /// 
        /// Allowed effects of a drag-and-drop operation.
        ///  
        /// 
        /// The target of the event. 
        ///  
        /// 
        /// The current mouse position of the target. 
        /// 
        internal DragEventArgs(IDataObject data, DragDropKeyStates dragDropKeyStates, DragDropEffects allowedEffects, DependencyObject target, Point point)
        {
            if (!DragDrop.IsValidDragDropKeyStates(dragDropKeyStates)) 
            {
                Debug.Assert(false, "Invalid dragDropKeyStates"); 
            } 

            if (!DragDrop.IsValidDragDropEffects(allowedEffects)) 
            {
                Debug.Assert(false, "Invalid allowedEffects");
            }
 
            if (target == null)
            { 
                Debug.Assert(false, "Invalid target"); 
            }
 
            this._data = data;
            this._dragDropKeyStates = dragDropKeyStates;
            this._allowedEffects = allowedEffects;
            this._target = target; 
            this._dropPoint = point;
            this._effects = allowedEffects; 
        } 

        #endregion Constructors 

        //------------------------------------------------------
        //
        //  Public Methods 
        //
        //----------------------------------------------------- 
 
        #region Public Methods
 
        /// 
        /// The point of drop operation that based on relativeTo.
        /// 
        public Point GetPosition(IInputElement relativeTo) 
        {
            Point dropPoint; 
 
            if (relativeTo == null)
            { 
                throw new ArgumentNullException("relativeTo");
            }

            dropPoint = new Point(0, 0); 

            if (_target != null) 
            { 
                // Translate the drop point from the drop target to the relative element.
                dropPoint = InputElement.TranslatePoint(_dropPoint, _target, (DependencyObject)relativeTo); 
            }

            return dropPoint;
        } 

        #endregion Public Methods 
 
        //------------------------------------------------------
        // 
        //  Public Properties
        //
        //------------------------------------------------------
 
        #region Public Properties
 
        ///  
        /// The data object of drop operation
        ///  
        public IDataObject Data
        {
            get { return _data; }
        } 

        ///  
        /// The DragDropKeyStates that indicates the current states for 
        /// physical keyboard keys and mouse buttons.
        ///  
        public DragDropKeyStates KeyStates
        {
            get { return _dragDropKeyStates; }
        } 

        ///  
        /// The allowed effects of drag and drop operation 
        /// 
        public DragDropEffects AllowedEffects 
        {
            get
            {
                return _allowedEffects; 
            }
        } 
 
        /// 
        /// The effects of drag and drop operation 
        /// 
        public DragDropEffects Effects
        {
            get 
            {
                return _effects; 
            } 

            set 
            {
                if (!DragDrop.IsValidDragDropEffects(value))
                {
                    throw new ArgumentException(SR.Get(SRID.DragDrop_DragDropEffectsInvalid, "value")); 
                }
 
                _effects = 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)
        { 
            DragEventHandler handler = (DragEventHandler)genericHandler;
            handler(genericTarget, this); 
        } 

        #endregion Protected Methods 

        //-----------------------------------------------------
        //
        //  Private Fields 
        //
        //----------------------------------------------------- 
 
        #region Private Fields
 
        private IDataObject _data;
        private DragDropKeyStates _dragDropKeyStates;
        private DragDropEffects _allowedEffects;
        private DragDropEffects _effects; 
        private DependencyObject _target;
        private Point _dropPoint; 
 
        #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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