Private Sub DrawEllipseRectangle(ByVal e As PaintEventArgs)

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

    ' Create rectangle for ellipse.
    Dim rect As New Rectangle(0, 0, 200, 100)

    ' Draw ellipse to screen.
    e.Graphics.DrawEllipse(blackPen, rect)
End Sub

Private Sub DrawEllipseRectangleF(ByVal e As PaintEventArgs)

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

    ' Create rectangle for ellipse.
    Dim rect As New RectangleF(0.0F, 0.0F, 200.0F, 100.0F)

    ' Draw ellipse to screen.
    e.Graphics.DrawEllipse(blackPen, rect)
End Sub

Private Sub DrawEllipseInt(ByVal e As PaintEventArgs)

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

    ' Create location and size of ellipse.
    Dim x As Integer = 0
    Dim y As Integer = 0
    Dim width As Integer = 200
    Dim height As Integer = 100

    ' Draw ellipse to screen.
    e.Graphics.DrawEllipse(blackPen, x, y, width, height)
End Sub

Private Sub DrawEllipseFloat(ByVal e As PaintEventArgs)

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

    ' Create location and size of ellipse.
    Dim x As Single = 0.0F
    Dim y As Single = 0.0F
    Dim width As Single = 200.0F
    Dim height As Single = 100.0F

    ' Draw ellipse to screen.
    e.Graphics.DrawEllipse(blackPen, x, y, width, height)
End Sub

' 导入命名空间
Imports System
Imports System.Windows.Forms
Imports System.Collections.Generic
Imports System.ComponentModel
Imports System.Drawing.Imaging
Imports System.Drawing

Public Class MainClass

   Shared Sub Main()
        Dim bm As New Bitmap(256, 256)

        ' Draw on it.
        Dim gr As Graphics = Graphics.FromImage(bm)
        gr.Clear(Color.White)
        gr.DrawEllipse(Pens.Red, 0, 0, bm.Width - 1, bm.Height - 1)
        gr.DrawLine(Pens.Green, 0, 0, bm.Width - 1, bm.Height - 1)
        gr.DrawLine(Pens.Blue, bm.Width - 1, 0, 0, bm.Height - 1)

        ' Save the result as a JPEG file.
        bm.Save("test.gif", ImageFormat.Gif)
   End Sub 

End Class