学步园

需要实现的功能是当鼠标滑过WPF窗体的textbox时，获取textbox的输入焦点。

步骤：

1.需要把此WPF的Topmost属性设置成true。

2.引用 win32 API 函数：

        [DllImport("user32.dll")]
        private static extern bool SetForegroundWindow(IntPtr hWnd);
        [DllImport("user32.dll")]
        private static extern IntPtr SetFocus(IntPtr hWnd);

2.添加Textbox的MouseEnter事件

private void tbWord_MouseEnter(object sender, MouseEventArgs e)
        {
            HwndSource source = (HwndSource)PresentationSource.FromVisual(this);
            IntPtr handle = source.Handle;
           
            bool b1 = BringWindowToTop(handle);
            System.Threading.Thread.Sleep(300);
            bool b = SetForegroundWindow(handle);
            System.Threading.Thread.Sleep(100);
  
            tbWord.Focus();
            tbWord.SelectAll();
        }

 程序演示： http://www.cnblogs.com/JimmyXiao/archive/2011/03/17/1987561.html