vb.net - 我需要在 vb.net 中将什么传递给这个子例程？

Question

Public Sub DrawRectangleInt(e As PaintEventArgs)

        ' Create pen. 
        Dim blackPen As New Pen(Color.Black, 3)

        ' Create location and size of rectangle. 
        Dim x As Integer = 0
        Dim y As Integer = 0
        Dim width As Integer = 200
        Dim height As Integer = 200

        ' Draw rectangle to screen.
        e.Graphics.DrawRectangle(blackPen, x, y, width, height)

    End Sub

当调用 Sub 时：

DrawRectangleInt()

我收到一条错误消息，说我需要为“e”传递一些东西，但是什么？

谢谢。

Answer 1

您可以从绘画事件中调用该子并将e变量传递给您的子，或者在您的子中创建 Graphics 对象。Using/End Using 块可以正确处理对象。

Public Sub DrawRectangleInt()

  ' Create pen. 
  Using blackPen As New Pen(Color.Black, 3)

    ' Create location and size of rectangle. 
    Dim x As Integer = 0
    Dim y As Integer = 0
    Dim width As Integer = 200
    Dim height As Integer = 200

    ' Draw rectangle to screen.
    Using g As Graphics = Me.CreateGraphics
      g.DrawRectangle(blackPen, x, y, width, height)
    End Using
  End Using
End Sub