如何：绘制空心形状
此示例在窗体上绘制空心椭圆和空心矩形。
示例
Private Sub DrawEllipse()
Dim myPen As New System.Drawing.Pen(System.Drawing.Color.Red)
Dim formGraphics As System.Drawing.Graphics
formGraphics = Me.CreateGraphics()
formGraphics.DrawEllipse(myPen, New Rectangle(0, 0, 200, 300))
myPen.Dispose()
formGraphics.Dispose()
End Sub
Private Sub DrawRectangle()
Dim myPen As New System.Drawing.Pen(System.Drawing.Color.Red)
Dim formGraphics As System.Drawing.Graphics
formGraphics = Me.CreateGraphics()
formGraphics.DrawRectangle(myPen, New Rectangle(0, 0, 200, 300))
myPen.Dispose()
formGraphics.Dispose()
End Sub
private void DrawEllipse()
{
System.Drawing.Pen myPen = new System.Drawing.Pen(System.Drawing.Color.Red);
System.Drawing.Graphics formGraphics;
formGraphics = this.CreateGraphics();
formGraphics.DrawEllipse(myPen, new Rectangle(0, 0, 200, 300));
myPen.Dispose();
formGraphics.Dispose();
}
private void DrawRectangle()
{
System.Drawing.Pen myPen = new System.Drawing.Pen(System.Drawing.Color.Red);
System.Drawing.Graphics formGraphics;
formGraphics = this.CreateGraphics();
formGraphics.DrawRectangle(myPen, new Rectangle(0, 0, 200, 300));
myPen.Dispose();
formGraphics.Dispose();
}
private:
void DrawEllipse()
{
System::Drawing::Pen^ myPen =
gcnew System::Drawing::Pen(System::Drawing::Color::Red);
System::Drawing::Graphics^ formGraphics;
formGraphics = this->CreateGraphics();
formGraphics->DrawEllipse(myPen, Rectangle(0, 0, 200, 300));
delete myPen;
delete formGraphics;
}
private:
void DrawRectangle()
{
System::Drawing::Pen^ myPen =
gcnew System::Drawing::Pen(System::Drawing::Color::Red);
System::Drawing::Graphics^ formGraphics;
formGraphics = this->CreateGraphics();
formGraphics->DrawRectangle(myPen, Rectangle(0, 0, 200, 300));
delete myPen;
delete formGraphics;
}
编译代码
不能在 Load 事件处理程序中调用此方法。 如果已调整该窗体的大小或者其他窗体遮蔽了该窗体，则不会重绘所绘制的内容。 若要自动重绘内容，应该重写 OnPaint 方法。
可靠编程
应该始终对使用系统资源的任何对象（如 Pen 和 Graphics 对象）调用 Dispose。