添加项目文件。

Util/MouseUtilities.cs

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+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Runtime.InteropServices;
+using System.Windows;
+using System.Windows.Media;
+
+namespace WPF.JoshSmith.Controls.Utilities
+{
+	/// <summary>
+	/// Provides access to the mouse location by calling unmanaged code.
+	/// </summary>
+	/// <remarks>
+	/// This class was written by Dan Crevier (Microsoft).  
+	/// http://blogs.msdn.com/llobo/archive/2006/09/06/Scrolling-Scrollviewer-on-Mouse-Drag-at-the-boundaries.aspx
+	/// </remarks>
+	public class MouseUtilities
+	{
+		[StructLayout( LayoutKind.Sequential )]
+		private struct Win32Point
+		{
+			public Int32 X;
+			public Int32 Y;
+		};
+
+		[DllImport( "user32.dll" )]
+		private static extern bool GetCursorPos( ref Win32Point pt );
+
+		[DllImport( "user32.dll" )]
+		private static extern bool ScreenToClient( IntPtr hwnd, ref Win32Point pt );
+
+		/// <summary>
+		/// Returns the mouse cursor location.  This method is necessary during 
+		/// a drag-drop operation because the WPF mechanisms for retrieving the
+		/// cursor coordinates are unreliable.
+		/// </summary>
+		/// <param name="relativeTo">The Visual to which the mouse coordinates will be relative.</param>
+		public static Point GetMousePosition( Visual relativeTo )
+		{
+			Win32Point mouse = new Win32Point();
+			GetCursorPos( ref mouse );
+
+			// Using PointFromScreen instead of Dan Crevier's code (commented out below)
+			// is a bug fix created by William J. Roberts.  Read his comments about the fix
+			// here: http://www.codeproject.com/useritems/ListViewDragDropManager.asp?msg=1911611#xx1911611xx
+			return relativeTo.PointFromScreen( new Point( (double)mouse.X, (double)mouse.Y ) );
+
+			#region Commented Out
+			//System.Windows.Interop.HwndSource presentationSource =
+			//    (System.Windows.Interop.HwndSource)PresentationSource.FromVisual( relativeTo );
+			//ScreenToClient( presentationSource.Handle, ref mouse );
+			//GeneralTransform transform = relativeTo.TransformToAncestor( presentationSource.RootVisual );
+			//Point offset = transform.Transform( new Point( 0, 0 ) );
+			//return new Point( mouse.X - offset.X, mouse.Y - offset.Y );
+			#endregion // Commented Out
+		}
+	}
+}