在窗体中添加一个ContextMenu1控件

Imports System.Drawing.Drawing2D

Public Class Form1
    Inherits System.Windows.Forms.Form

#Region " Windows 窗体设计器生成的代码 "

    Public Sub New()
        MyBase.New()

        '该调用是 Windows 窗体设计器所必需的。
        InitializeComponent()

        '在 InitializeComponent() 调用之后添加任何初始化

    End Sub

    '窗体重写处置以清理组件列表。
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub

    'Windows 窗体设计器所必需的
    Private components As System.ComponentModel.IContainer

    '注意：以下过程是 Windows 窗体设计器所必需的
    '可以使用 Windows 窗体设计器修改此过程。
    '不要使用代码编辑器修改它。
    Friend WithEvents ContextMenu1 As System.Windows.Forms.ContextMenu
    Friend WithEvents MenuItem1 As System.Windows.Forms.MenuItem
    Friend WithEvents MenuItem2 As System.Windows.Forms.MenuItem
    Friend WithEvents MenuItem3 As System.Windows.Forms.MenuItem
    Friend WithEvents MenuItem4 As System.Windows.Forms.MenuItem
    Friend WithEvents MenuItem5 As System.Windows.Forms.MenuItem
    Friend WithEvents MenuItem6 As System.Windows.Forms.MenuItem
    Friend WithEvents MenuItem7 As System.Windows.Forms.MenuItem
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Dim resources As System.ComponentModel.ComponentResourceManager = New System.ComponentModel.ComponentResourceManager(GetType(Form1))
        Me.ContextMenu1 = New System.Windows.Forms.ContextMenu
        Me.MenuItem1 = New System.Windows.Forms.MenuItem
        Me.MenuItem2 = New System.Windows.Forms.MenuItem
        Me.MenuItem3 = New System.Windows.Forms.MenuItem
        Me.MenuItem4 = New System.Windows.Forms.MenuItem
        Me.MenuItem5 = New System.Windows.Forms.MenuItem
        Me.MenuItem6 = New System.Windows.Forms.MenuItem
        Me.MenuItem7 = New System.Windows.Forms.MenuItem
        Me.SuspendLayout()
        '
        'ContextMenu1
        '
        Me.ContextMenu1.MenuItems.AddRange(New System.Windows.Forms.MenuItem() {Me.MenuItem1,Me.MenuItem2,Me.MenuItem3,Me.MenuItem4,Me.MenuItem5,Me.MenuItem6,Me.MenuItem7})
        '
        'MenuItem1
        '
        Me.MenuItem1.Index = 0
        Me.MenuItem1.Text = "椭圆"
        '
        'MenuItem2
        '
        Me.MenuItem2.Index = 1
        Me.MenuItem2.Text = "扇形"
        '
        'MenuItem3
        '
        Me.MenuItem3.Index = 2
        Me.MenuItem3.Text = "圆形"
        '
        'MenuItem4
        '
        Me.MenuItem4.Index = 3
        Me.MenuItem4.Text = "环形"
        '
        'MenuItem5
        '
        Me.MenuItem5.Index = 4
        Me.MenuItem5.Text = "三角"
        '
        'MenuItem6
        '
        Me.MenuItem6.Index = 5
        Me.MenuItem6.Text = "恢复矩形"
        '
        'MenuItem7
        '
        Me.MenuItem7.Index = 6
        Me.MenuItem7.Text = "退出"
        '
        'Form1
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(14,37)
        Me.BackgroundImage = CType(resources.GetObject("$this.BackgroundImage"),System.Drawing.Image)
        Me.ClientSize = New System.Drawing.Size(344,304)
        Me.ContextMenu = Me.ContextMenu1
        Me.Font = New System.Drawing.Font("Arial Narrow",24.0!,System.Drawing.FontStyle.Bold,System.Drawing.GraphicsUnit.Point,CType(0,Byte))
        Me.FormBorderStyle = System.Windows.Forms.FormBorderStyle.Fixed3D
        Me.Name = "Form1"
        Me.Text = "Form1"
        Me.ResumeLayout(False)

    End Sub

#End Region

    Private Sub MenuItem1_Click(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles MenuItem1.Click,MenuItem2.Click,MenuItem3.Click,MenuItem4.Click,MenuItem5.Click,MenuItem6.Click,MenuItem7.Click

        Dim p As GraphicsPath = New GraphicsPath()

        Select Case CType(sender,MenuItem).Text
            Case "椭圆"

                Dim Width As Integer = Me.ClientSize.Width
                Dim Height As Integer = Me.ClientSize.Height
                p.AddEllipse(0,20,Width - 50,Height - 100)
                
                '根据要绘制椭圆的形状来填写AddEllipse方法中椭圆对应的相应参数

            Case "扇形"
                p.AddPie(10,10,250,5,150)
                '根据要实现的扇形形状来填写AddPie方法中的相应参数

            Case "圆形"
                Dim Width As Integer = Me.ClientSize.Width
                Dim Height As Integer = Me.ClientSize.Height
                p.AddEllipse(0,Height,Height)
                '圆形即是椭圆的一种特例，

            Case "环形"
                Dim Height As Integer = Me.ClientSize.Height
                Dim width As Integer = 100
                p.AddEllipse(0,Height)
                'p.AddRectangle(New Rectangle(width,width,width))
                p.AddEllipse(width,Height - (width * 2),Height - (width * 2))
                '根据环形的形状来分别填写AddEllipse方法中相应的参数

            Case "三角"
                p.AddLine(0,150)
                p.AddLine(250,150,300)
                p.AddLine(0,300)
                '根据三角形的形状特征来分别填写AddLine方法中相应的参数


            Case "恢复矩形"
                p.AddRectangle(New Rectangle(0,Me.Width,Me.Height))
                '用窗体尺寸矩形填充addrectangle()方法

            Case "退出"
                Close()
        End Select
        '设置窗体的外形
        Me.Region = New Region(p)

    End Sub

    Private Sub ContextMenu1_Popup(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles ContextMenu1.Popup

    End Sub

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

    End Sub
End Class