利用C#实现标注式消息提示窗口

……
public enum ArrowLocation
{
　TopLeft,
　TopRight,
　BottomLeft,
　BottomRight
}

private void SetInfoWindowRegion()
{
　if (!this.IsHandleCreated)
　　return;
　System.Drawing.Size windowSize = this.Size;
　Point[] ArrowPoints = new Point[3];
　Point topLeftPoint = Point.Empty;
　Point bottomRightPoint = (Point)windowSize;
　switch (this.GetArrowLocation)
　{
　　case ArrowLocation.TopLeft:
　　　……
　　case ArrowLocation.TopRight:
　　　……
　　case ArrowLocation.BottomLeft:
　　　……
　　case ArrowLocation.BottomRight:
　　　……
　}
　……
　……
　if ((this.GetArrowLocation == ArrowLocation.TopLeft) ||
(this.GetArrowLocation == ArrowLocation.TopRight))
　{
　　gPath.AddArc(topLeftPoint.X, rectY2 - arcRadius, arcDia, arcDia, 90, 90);
　　gPath.AddLine(topLeftPoint.X, rectY2, topLeftPoint.X, rectY1);
　　gPath.AddArc(topLeftPoint.X, topLeftPoint.Y, arcDia, arcDia, 180, 90);
　　gPath.AddLine(rectX1, topLeftPoint.Y, ArrowPoints[0].X, topLeftPoint.Y);

数据挖掘论坛

　　gPath.AddLines(ArrowPoints);
　　gPath.AddLine(ArrowPoints[2].X, topLeftPoint.Y, rectX2, topLeftPoint.Y);
　　gPath.AddArc(rectX2 - arcRadius, topLeftPoint.Y, arcDia, arcDia, 270, 90);
　　gPath.AddLine(bottomRightPoint.X, rectY1, bottomRightPoint.X, rectY2);
　　gPath.AddArc(rectX2 - arcRadius, rectY2 - arcRadius, arcDia, arcDia, 0, 90);
　　gPath.AddLine(rectX2, bottomRightPoint.Y, rectX1, bottomRightPoint.Y);
　}
　else
　{
　　gPath.AddLine(rectX1, topLeftPoint.Y, rectX2, topLeftPoint.Y);
　　gPath.AddArc(rectX2 - arcRadius, topLeftPoint.Y, arcDia, arcDia, 270, 90);
　　gPath.AddLine(bottomRightPoint.X, rectY1, bottomRightPoint.X, rectY2);
　　gPath.AddArc(rectX2 - arcRadius, rectY2 - arcRadius, arcDia, arcDia, 0, 90);
　　gPath.AddLine(rectX2, bottomRightPoint.Y, ArrowPoints[0].X, bottomRightPoint.Y);
　　gPath.AddLines(ArrowPoints);
　　gPath.AddLine(ArrowPoints[2].X, bottomRightPoint.Y, rectX1, bottomRightPoint.Y);
　　gPath.AddArc(topLeftPoint.X, rectY2 - arcRadius, arcDia, arcDia, 90, 90);

数据挖掘论坛

　　gPath.AddLine(topLeftPoint.X, rectY2, topLeftPoint.X, rectY1);
　　gPath.AddArc(topLeftPoint.X, topLeftPoint.Y, arcDia, arcDia, 180, 90);
　}
　gPath.CloseFigure();
　this.Region = new Region(this.gPath);
}

public static Point AnchorPointFromControl(Control anchorControl)
{
　if (anchorControl == null)
　throw new ArgumentException();
　Point controlLocation = anchorControl.Location;
　System.Drawing.Size controlSize = anchorControl.Size;

　if (anchorControl.Parent != null)
　　controlLocation = anchorControl.Parent.PointToScreen(controlLocation);
　return controlLocation + new Size(controlSize.Width / 2, controlSize.Height / 2);
}

protected override void OnPaint(PaintEventArgs e)
{
　Pen p = new Pen(Color.Black , 2);
　e.Graphics.DrawPath(p, gPath);
　base.OnPaint(e);
}

……
private InfoWindow iw;
……
private void button1_Click(object sender, EventArgs e)
{
　iw = new InfoWindow();
　iw.ShowInfoWindow(label1, "关于标签组件的提示说明。");
}
private void button3_Click(object sender, EventArgs e)
{
　iw = new InfoWindow();
　iw.ShowInfoWindow(button2, "关于按钮组件的提示说明。");
}

private void button4_Click(object sender, EventArgs e)
{
　iw = new InfoWindow();
　iw.ShowInfoWindow(textBox1, "关于文本框组件的提示说明。");
}