vb.net - 捕获矩形

Question

这有效。它在面板上绘制一个简单的矩形:

    Dim g As Graphics
    Dim fPen As Pen
    g = aPanel.CreateGraphics()

    fPen = New Pen(Color.Blue)
    Dim PointX As Point = New Point(10, 20)
    Dim PointY As Point = New Point(50, 50)

    g.DrawRectangle(fPen, PointY.X, PointY.Y, 50, 50)

一切都是对象 - 但我如何引用这个矩形？
我想在稍后在代码中创建椭圆时使用这个矩形作为参数之一(即在矩形中绘制椭圆) - 为什么我不能执行以下操作？

    Dim g As Graphics
    Dim fPen As Pen
    g = aPanel.CreateGraphics()

    fPen = New Pen(Color.Blue)
    Dim PointX As Point = New Point(10, 20)
    Dim PointY As Point = New Point(50, 50)

    Dim r As Rectangle
    r = New Rectangle(g.DrawRectangle(fPen, PointY.X, PointY.Y, 50, 50)) '<<<errors here
    g.DrawEllipse(fPen, r)

Answer 1

声明你的矩形并使用它的值:

Dim r As New Rectangle(10, 50, 50, 50)

g.DrawRectangle(fPen, r.Location.X, r.Location.Y, r.Width, r.Height)
g.DrawEllipse(fPen, r)