用 VB.Net 在我的表单上画圈答案

【问题标题】：Draw circle over my form with VB.Net用 VB.Net 在我的表单上画圈
【发布时间】：2012-10-22 15:20:04
【问题描述】：

如何在我的表单上画圆？

我尝试过的：

Dim bmp As New Bitmap(Me.Width, Me.Height)
cWidth = 3
Me.BackgroundImage = Circle (Me.Width, Me.Height,bmp,cWidth)

【问题讨论】：

标签： .net vb.net winforms

【解决方案1】：

覆盖 OnPaint 事件处理程序并从那里执行，f.ex：

Protected Overrides Sub OnPaint(e As System.Windows.Forms.PaintEventArgs)
    MyBase.OnPaint(e)

    Dim myPen As New Pen(Color.Red, 3) 'to set width of pen

    e.Graphics.DrawEllipse(myPen, 0, 0, _
                           Me.ClientSize.Width - 1, Me.ClientSize.Height - 1)

    myPen.Dispose()

End Sub

【讨论】：

没问题。我没有实现笔宽补偿，但实现补偿很简单。

【解决方案2】：

好的，这是带有圆圈 ;-)

Public Class Form1
    Private Sub Form1_Paint(sender As System.Object, e As System.Windows.Forms.PaintEventArgs) Handles MyBase.Paint
        Dim p As Pen
        Dim d As Integer
        Dim x As Integer

        d = Math.Min(Me.ClientRectangle.Width, Me.ClientRectangle.Height)
        x = Me.ClientRectangle.Width / 2 - d / 2

        p = New Pen(Brushes.Navy, 7)
        e.Graphics.DrawEllipse(p, New Rectangle(x, 0, d, d))
    End Sub

    Private Sub Form1_Resize(sender As System.Object, e As System.EventArgs) Handles MyBase.Resize
        Me.Invalidate()
    End Sub
End Class

【讨论】：