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在Windows中，句柄是一个系统内部数据结构的引用。例如当你操作一个窗口，或说是一个Delphi窗体时，系统会给你一个该窗口的句柄，系统会通知你：你正在操作142号窗口，就此你的应用程序就能要求系统对142号窗口进行操作——移动窗口、改变窗口大小、把窗口极小化为图标等。实际上许多 Windows API函数把句柄作为它的第一个参数，如GDI（图形设备接口）句柄、菜单句柄、实例句柄、位图句柄等，不仅仅局限于窗口函数。换句话说，句柄是一种内部代码，通过它能引用受系统控制的特殊元素，如窗口、位图、图标、内存块、光标、字体、菜单等。
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Private Declare Function GetWindowLong Lib "user32" Alias "GetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long) As Long -
Private Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long -
Private Declare Function SetLayeredWindowAttributes Lib "user32" (ByVal hwnd As Long, ByVal crKey As Long, ByVal bAlpha As Byte, ByVal dwFlags As Long) As Long -
Private Const WS_EX_LAYERED = &H80000 -
Private Const GWL_EXSTYLE = (-20) -
Private Const LWA_ALPHA = &H2 -
Private Sub Form_Activate() -
On Error Resume Next -
For i = 0 To 150 Step 2.5 -
SetLayeredWindowAttributes Me.hwnd, 0, i, LWA_ALPHA -
DoEvents -
Next i -
End Sub -
Private Sub Form_load() -
Dim rtn As Long -
rtn = GetWindowLong(Me.hwnd, GWL_EXSTYLE) -
rtn = rtn Or WS_EX_LAYERED -
SetWindowLong Me.hwnd, GWL_EXSTYLE, rtn -
SetLayeredWindowAttributes Me.hwnd, 0, 0, LWA_ALPHA -
End Sub
-
//获取窗口标题 -
[DllImport("user32", SetLastError = true)] -
public static extern int GetWindowText( -
IntPtr hWnd,//窗口句柄 -
StringBuilder lpString,//标题 -
int nMaxCount //最大值 -
); -
//获取类的名字 -
[DllImport("user32.dll")] -
private static extern int GetClassName( -
IntPtr hWnd,//句柄 -
StringBuilder lpString, //类名 -
int nMaxCount //最大值 -
); -
//根据坐标获取窗口句柄 -
[DllImport("user32")] -
private static extern IntPtr WindowFromPoint( -
Point Point //坐标 -
); -
private void timer1_Tick(object sender, EventArgs e) -
{
-
int x = Cursor.Position.X; -
int y = Cursor.Position.Y; -
Point p = new Point(x, y); -
IntPtr formHandle = WindowFromPoint(p);//得到窗口句柄 -
StringBuilder title = new StringBuilder(256); -
GetWindowText(formHandle, title, title.Capacity);//得到窗口的标题 -
StringBuilder className = new StringBuilder(256); -
GetClassName(formHandle, className, className.Capacity);//得到窗口的句柄 -
this.textBox1.Text = title.ToString(); -
this.textBox2.Text = formHandle.ToString(); -
this.textBox3.Text = className.ToString(); -
}
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