Visual 2008 下VB9.0在窗体上绘线条

'根据相关代码修改而来。WinDowsXp +Spack3.0 +VS2008下调试通过

Imports System
Imports System.Drawing
Imports System.Windows.Forms
Imports System.Collections

Public Class Form1
    Private Enum Tool
        Line = 1
        Rectangle
    End Enum

    Private myTool As Tool
    Private ptDown As Point
    Private ptUp As Point

    Public ptStart As New ArrayList()
    Public ptEnd As New ArrayList()

    Private bDrawing As Boolean

 

    Private Sub DrawRectangleleOnClick(ByVal sender As Object, ByVal e As EventArgs)
        myTool = Tool.Rectangle
    End Sub

    Private Sub DrawLineOnClik(ByVal sender As Object, ByVal e As EventArgs)
        myTool = Tool.Line
    End Sub

    Protected Overrides Sub OnMouseDown(ByVal e As MouseEventArgs)

        If e.Button = MouseButtons.Left AndAlso _
         myTool = Tool.Line Then

            ptDown = New Point(e.X, e.Y)
            ptStart.Add(ptDown)
            bDrawing = True

        End If

    End Sub

    Protected Overrides Sub OnMouseMove(ByVal e As MouseEventArgs)

        Select Case myTool
            Case Tool.Line
                Cursor.Current = Cursors.Cross
            Case Tool.Rectangle
                Cursor.Current = Cursors.VSplit

        End Select

    End Sub
    Protected Overrides Sub OnMouseUp(ByVal e As MouseEventArgs)
        If Not bDrawing Then Return

        Select Case myTool
            Case Tool.Line

                Dim g As Graphics = CreateGraphics()
                ptUp = New Point(e.X, e.Y)
                g.DrawLine(New Pen(ForeColor), ptDown, ptUp)
                g.Dispose()
                ptEnd.Add(ptUp)
                bDrawing = False

            Case Tool.Rectangle
                '
                '畫長方形自己加
                '

        End Select

    End Sub

    Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
        Dim g As Graphics = e.Graphics

        Dim i As Int32
        Dim myptStart() As Point = DirectCast(ptStart.ToArray(GetType(Point)), Point())
        Dim myptEnd() As Point = DirectCast(ptEnd.ToArray(GetType(Point)), Point())

        For i = 0 To ptEnd.Count - 1

            If myptStart.Length >= 0 Then
                g.DrawLine(New Pen(ForeColor), myptStart(i), myptEnd(i))
            End If
        Next i
    End Sub

    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        With Me
            .Text = "My Drawing"
            .ForeColor = SystemColors.WindowText
            .BackColor = SystemColors.Window
            .Menu = New MainMenu()
            .ResizeRedraw = True
        End With

        Menu.MenuItems.Add("&Tool")
        Menu.MenuItems(0).MenuItems.Add("&Line", AddressOf DrawLineOnClik)
        Menu.MenuItems(0).MenuItems.Add("&Rectangle", AddressOf DrawRectangleleOnClick)
        '
        '可能要畫其它圖形的按鈕自己加
        '

    End Sub
End Class