自定义控件检查是否已启动调整大小
本文关键字:调整 启动 检查 是否 自定义控件 | 更新日期: 2023-09-27 17:51:19
我已经创建了一个名为Ellipse
的自定义Control
。我能够调整大小,移动,并绘制这个Ellipse
。现在我正试图为调整大小添加撤销/重做功能。用户可以在右下角调整控件的大小。此时,只要光标位于Control
的右下角,控件就会打印hello。但是我想要的是,当用户开始调整大小(因此鼠标左键按下,光标在右下角)时,打印hello(仅一次)。如何做到这一点,或者是否有另一种(更好的)方法来做到这一点?
Ellipse.cs
class Ellipse : Control
{
private Point mDown { get; set; }
public Ellipse()
{
SetStyle(ControlStyles.SupportsTransparentBackColor, true);
this.BackColor = Color.Transparent;
this.DoubleBuffered = true;
this.ResizeRedraw = true;
}
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
// Draw a black ellipse in the rectangle represented by the control.
e.Graphics.FillEllipse(Brushes.Black, 0, 0, Width, Height);
}
protected override void OnMouseDown(MouseEventArgs e)
{
base.OnMouseDown(e);
mDown = e.Location;
}
protected override void OnMouseMove(MouseEventArgs e)
{
// Call MyBase.OnMouseMove to activate the delegate.
base.OnMouseMove(e);
if (e.Button == MouseButtons.Left)
{
Location = new Point(e.X + Left - mDown.X, e.Y + Top - mDown.Y);
}
}
/* Allow resizing at the bottom right corner */
protected override void WndProc(ref Message m)
{
const int wmNcHitTest = 0x84;
const int htBottomLeft = 16;
const int htBottomRight = 17;
if (m.Msg == wmNcHitTest)
{
Console.WriteLine("Hello");
int x = (int)(m.LParam.ToInt64() & 0xFFFF);
int y = (int)((m.LParam.ToInt64() & 0xFFFF0000) >> 16);
Point pt = PointToClient(new Point(x, y));
Size clientSize = ClientSize;
if (pt.X >= clientSize.Width - 16 && pt.Y >= clientSize.Height - 16 && clientSize.Height >= 16)
{
m.Result = (IntPtr)(IsMirrored ? htBottomLeft : htBottomRight);
return;
}
}
base.WndProc(ref m);
}
我会尝试添加更多消息来检查鼠标是否在非客户端区域下降,然后另一个消息用于确定大小以完成事务:
private bool userResizing = false;
protected override void WndProc(ref Message m) {
const int wmNcHitTest = 0x84;
const int htBottomLeft = 16;
const int htBottomRight = 17;
const int WM_EXITSIZEMOVE = 0x232;
const int WM_NCLBUTTONDWN = 0xA1;
if (m.Msg == WM_NCLBUTTONDWN) {
if (!userResizing) {
userResizing = true;
Console.WriteLine("Start Resizing");
}
} else if (m.Msg == WM_EXITSIZEMOVE) {
if (userResizing) {
userResizing = false;
Console.WriteLine("Finish Resizing");
}
} else if (m.Msg == wmNcHitTest) {
int x = (int)(m.LParam.ToInt64() & 0xFFFF);
int y = (int)((m.LParam.ToInt64() & 0xFFFF0000) >> 16);
Point pt = PointToClient(new Point(x, y));
Size clientSize = ClientSize;
if (pt.X >= clientSize.Width - 16 &&
pt.Y >= clientSize.Height - 16 &&
clientSize.Height >= 16) {
m.Result = (IntPtr)(IsMirrored ? htBottomLeft : htBottomRight);
return;
}
}
base.WndProc(ref m);
}