Dim RcDraw As Rectangle
Dim PenWidth As Integer = 5


Private Sub Form1_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles MyBase.MouseDown

    ' Determine the initial rectangle coordinates...

    RcDraw.X = e.X
    RcDraw.Y = e.Y

End Sub

Private Sub Form1_MouseUp(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles MyBase.MouseUp

    ' Determine the width and height of the rectangle...

    If e.X < RcDraw.X Then
        RcDraw.Width = RcDraw.X - e.X
        RcDraw.X = e.X
    Else
        RcDraw.Width = e.X - RcDraw.X
    End If

    If e.Y < RcDraw.Y Then
        RcDraw.Height = RcDraw.Y - e.Y
        RcDraw.Y = e.Y
    Else
        RcDraw.Height = e.Y - RcDraw.Y
    End If

    ' Force a repaint of the region occupied by the rectangle...

    Me.Invalidate(RcDraw)

End Sub

Private Sub Form1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles MyBase.Paint

    ' Draw the rectangle...

    e.Graphics.DrawRectangle(New Pen(Color.Blue, PenWidth), RcDraw)

End Sub

' This example creates a PictureBox control on the form and draws to it. 
' This example assumes that the Form_Load event handler method is connected 
' to the Load event of the form.
Private pictureBox1 As New PictureBox()
Private fnt as New Font("Arial", 10)

Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
    ' Dock the PictureBox to the form and set its background to white.
    pictureBox1.Dock = DockStyle.Fill
    pictureBox1.BackColor = Color.White
    ' Connect the Paint event of the PictureBox to the event handler method.
    AddHandler pictureBox1.Paint, AddressOf Me.pictureBox1_Paint

    ' Add the PictureBox control to the Form.
    Me.Controls.Add(pictureBox1)
End Sub


Private Sub pictureBox1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs)
    ' Create a local version of the graphics object for the PictureBox.
    Dim g As Graphics = e.Graphics

    ' Draw a string on the PictureBox.
    g.DrawString("This is a diagonal line drawn on the control", _
        fnt, Brushes.Red, New PointF(30.0F, 30.0F))
    ' Draw a line in the PictureBox.
    g.DrawLine(System.Drawing.Pens.Red, pictureBox1.Left, _ 
        pictureBox1.Top, pictureBox1.Right, pictureBox1.Bottom)
End Sub

' 导入命名空间
Imports System
Imports System.Drawing
Imports System.Windows.Forms
Imports System.Drawing.Text

Public Class MainClass

   Shared Sub Main()
        Dim myform As Form = New FrmDrawing()
        Application.Run(myform)
   End Sub ' Main

End Class

Public Class FrmDrawing
   Inherits System.Windows.Forms.Form

   Public Sub New()
      MyBase.New()

      Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
      Me.BackColor = System.Drawing.SystemColors.AppWorkspace
      Me.ClientSize = New System.Drawing.Size(472, 157)
   End Sub

   Protected Overrides Sub OnPaint(ByVal paintEvent As PaintEventArgs)

      Dim graphicsObject As Graphics = paintEvent.Graphics
      Dim rectangle1 As Rectangle = New Rectangle(15, 35, 80, 80)
      Dim brush1 As SolidBrush = New SolidBrush(Color.Firebrick)
      Dim pen1 As Pen = New Pen(brush1, 1)
      Dim brush2 As SolidBrush = New SolidBrush(Color.DarkBlue)
      Dim pen2 As Pen = New Pen(brush2, 1)

      rectangle1.Location = New Point(100, 35)
      graphicsObject.DrawRectangle(pen1, rectangle1)
      graphicsObject.DrawArc(pen2, rectangle1, 0, 110)
   End Sub

End Class