利用NativeWindow监视WndProc消息

在写Windows应用程序的时候，经常会碰到需要修改例如MessageBox或者FileDialog的外观
此时我们需要监视 WndProc的消息
当然也可以直接调用API实现，具体方法请参考
http://www.codeproject.com/csharp/GetSaveFileName.asp?df=100&forumid=96342&exp=0&select=1950454
主要代码如下

 using System; using System.Runtime.InteropServices; using System.Windows.Forms; using System.Collections.Generic; namespace testApplication1 { public delegate void HookWndProcHandler(ref Message m); public class HookWndProc { private Dictionary<Control, NativeWindow> nativeWindows = new Dictionary<Control, NativeWindow>(); public event HookWndProcHandler WndProcEvent; public void BeginHookProc(Control control) { if(nativeWindows.ContainsKey(control)) { return; } nativeWindows.Add(control, new HookNativeWindow(this, control)); } public void EndHookProc(Control control) { if(!nativeWindows.ContainsKey(control)) { return; } NativeWindow window = nativeWindows[control]; nativeWindows.Remove(control); window.ReleaseHandle(); window = null; } protected virtual void WndProc(ref Message m) { FireWndProcEvent(ref m); } protected void FireWndProcEvent(ref Message m) { if (WndProcEvent != null) { WndProcEvent(ref m); } } #region NativeWindow protected class HookNativeWindow : NativeWindow { private HookWndProc hookWndProc; public HookNativeWindow(HookWndProc hookWndProc, Control control) { this.hookWndProc = hookWndProc; if (control.IsHandleCreated) { AssignHandle(control.Handle); } else { control.HandleCreated += new EventHandler(OnControlHandleCreated); } control.HandleDestroyed += new EventHandler(OnControlHandleDestroyed); } private void OnControlHandleCreated(object sender, EventArgs e) { AssignHandle(((Control)sender).Handle); } private void OnControlHandleDestroyed(object sender, EventArgs e) { ReleaseHandle(); } [System.Security.Permissions.PermissionSet(System.Security.Permissions.SecurityAction.Demand, Name = "FullTrust")] protected override void WndProc(ref Message m) { hookWndProc.WndProc(ref m); base.WndProc(ref m); } } #endregion } }

调用方法，以更改MessageBox的OK按钮文本为例

            HookWndProc hookWndProc  =   new  HookWndProc();
            hookWndProc.WndProcEvent  +=   new  HookWndProcHandler(hookWndProc_WndProcEvent);
            hookWndProc.BeginHookProc( this );
            MessageBox.Show( " MSG APP " ,  " MessageBoxCaption " , MessageBoxButtons.OKCancel);
            hookWndProc.EndHookProc( this );

private   void  hookWndProc_WndProcEvent( ref  Message m)
         ... {
            IntPtr wnd = FindWindow(null, "MessageBoxCaption");

            if (wnd != IntPtr.Zero)
            ...{
                SetDlgItemText(wnd, 1, "需要修改的文本");
            }
        }
        [DllImport( " user32.dll " , EntryPoint  =   " FindWindow " , CharSet  =  CharSet.Auto)]
         private   extern   static  IntPtr FindWindow( string  lpClassName,  string  lpWindowName);

        [DllImport( " user32.dll " )]
         public   static   extern  IntPtr SetDlgItemText(IntPtr hwnd,  int  id,  string  caption);

也就是说在WndProcEvent事件里面你可以写上你所需要做的事情

如果需要修改FileDialog的外观
则需要在WndProcEvent事件里面写上如下代码

if  (m.Msg  ==  WM_ENTERIDLE)
... {
    uint dialogHandle = (uint)m.LParam;
    uint listviewHandle = FindWindowEx(dialogHandle, 0, "SHELLDLL_DefView", "");
    if (listviewHandle != 0 && listviewHandle != lastListViewHandle)
    ...{
        SendMessage(listviewHandle, WM_COMMAND, (uint)View, 0);
}
lastListViewHandle = listviewHandle;



    /**//// <summary>
    /// FileListViewType
    /// </summary>
    public enum FileListView
    ...{
        Icons = 0x7029,
        SmallIcons = 0x702a,
        List = 0x702b,
        Details = 0x702c,
        Thumbnails = 0x7031,
        XpThumbnails = 0x702d
    }


        /**//// <summary>
        /// win message : command
        /// </summary>
        private const uint WM_COMMAND = 0x0111;

        /**//// <summary>
        /// win message : enter idle
        /// </summary>
        private const uint WM_ENTERIDLE = 0x0121;

        /**//// <summary>
        /// listview type
        /// </summary>
        private FileListView view = FileListView.Thumbnails;

        /**//// <summary>
        /// dialog handle
        /// </summary>
        private uint lastListViewHandle = 0;

DllImports
#region DllImports

        [DllImport("user32.dll", EntryPoint="SendMessageA", CallingConvention=CallingConvention.StdCall,CharSet=CharSet.Ansi)] 
        private static extern uint SendMessage(uint Hdc, uint Msg_Const, uint wParam, uint lParam);

        [DllImport("user32.dll", EntryPoint="FindWindowExA", CallingConvention=CallingConvention.StdCall,CharSet=CharSet.Ansi)] 
        private static extern uint FindWindowEx(uint hwndParent, uint hwndChildAfter, string lpszClass, string lpszWindow);

        #endregion

 

 

 

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