这在winapi中是可能的,窗口管理器发送WM_NCHITTEST消息来询问鼠标在控件的哪个部分。您可以做的是返回 HTTRANSPARENT,它会询问父窗口。这是一个实现此功能的示例 UserControl。捕获消息需要重写 WndProc():
public partial class UserControl1 : UserControl {
public UserControl1() {
InitializeComponent();
paths = new List<GraphicsPath>();
GraphicsPath example = new GraphicsPath();
example.AddEllipse(new Rectangle(10, 10, 50, 30));
paths.Add(example);
}
List<GraphicsPath> paths;
protected override void OnPaint(PaintEventArgs e) {
foreach (var path in paths) e.Graphics.FillPath(Brushes.Blue, path);
base.OnPaint(e);
}
protected override void WndProc(ref Message m) {
base.WndProc(ref m);
// Trap WM_NCHITTEST on the client area
if (m.Msg == 0x84 && m.Result == (IntPtr)1) {
Point pos = new Point(m.LParam.ToInt32());
pos = this.PointToClient(pos);
bool oncurve = false;
foreach (var path in paths)
if (path.IsVisible(pos)) oncurve = true;
if (!oncurve) m.Result = (IntPtr)(-1); // HTTRANSPARENT
}
}
}
测试代码形式:
private void userControl11_MouseMove(object sender, MouseEventArgs e) {
Console.WriteLine("On shape {0}", e.Location);
}
private void Form1_MouseMove(object sender, MouseEventArgs e) {
Console.WriteLine("On form {0}", e.Location);
}