form1.vb

《新编VB.NET 2005程序设计从入门到精通》源码 网上找的

Imports System.Runtime.InteropServices
Public Class Form1


    Private pointList As ArrayList

    Private Sub button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles button1.Click
        '构造颜色对话框 
        Dim cdlg As New ColorDialog()
        If cdlg.ShowDialog() = Windows.Forms.DialogResult.OK Then
            '把选取的颜色设为按钮前景色 
            button1.ForeColor = cdlg.Color
            '刷新窗口 
            Me.Invalidate(Me.ClientRectangle)
        End If
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        pointList = New ArrayList()
    End Sub

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

        '用当前鼠标位置构造Point对象 
        Dim pt As New Point(e.X, e.Y)
        '加入到数据中 
        pointList.Add(pt)
        '刷新窗口 
        Me.Invalidate(Me.ClientRectangle)
    End Sub

    Private Sub Form1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles Me.Paint
        Dim g As Graphics = e.Graphics
        '使用指定颜色和宽度构造画笔对象 
        Dim pen As New Pen(button1.ForeColor, Single.Parse(textBox1.Text))
        For i As Integer = 0 To pointList.Count - 2
            '绘制直线 
            g.DrawLine(pen, DirectCast(pointList(i), Point), DirectCast(pointList(i + 1), Point))
        Next
    End Sub

    Private Sub button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles button2.Click
        '构造保存对话框 
        Dim sfdlg As New SaveFileDialog()
        '设置对话框属性 
        sfdlg.Filter = "Point Connector File(*.ptc)|*.ptc|All Files(*.*)|*.*"
        sfdlg.FilterIndex = 1
        '数据流 
        Dim fs As IO.FileStream = Nothing
        Dim bw As IO.BinaryWriter = Nothing
        If sfdlg.ShowDialog() = Windows.Forms.DialogResult.OK Then
            Try
                '使用文件名称创建新文件 
                fs = New IO.FileStream(sfdlg.FileName, IO.FileMode.Create, System.IO.FileAccess.Write)
                '构造二进制写入类 
                bw = New IO.BinaryWriter(fs)
                '写入线条宽度 
                bw.Write(Single.Parse(textBox1.Text))
                '写入线条颜色 
                bw.Write(button1.ForeColor.ToArgb())
                '写入点的个数 
                bw.Write(pointList.Count)
                For i As Integer = 0 To pointList.Count - 1
                    '写入点的坐标 
                    bw.Write(DirectCast(pointList(i), Point).X)
                    bw.Write(DirectCast(pointList(i), Point).Y)
                Next
            Catch excep As Exception
                MessageBox.Show(excep.Message.ToString(), "出错", MessageBoxButtons.OK, MessageBoxIcon.[Error])
            Finally
                '关闭流 
                bw.Close()
                fs.Close()
            End Try
        End If
    End Sub

    Private Sub button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles button3.Click
        '构造打开文件对话框 
        Dim ofdlg As New OpenFileDialog()
        '设置对话框属性 
        ofdlg.Filter = "Point Connector File(*.ptc)|*.ptc|All Files(*.*)|*.*"
        ofdlg.FilterIndex = 1
        '数据流 
        Dim fs As IO.FileStream = Nothing
        Dim br As IO.BinaryReader = Nothing
        If ofdlg.ShowDialog() = Windows.Forms.DialogResult.OK Then
            Try
                '使用用户指定名称构造FileStream对象 
                fs = New IO.FileStream(ofdlg.FileName, IO.FileMode.Create, System.IO.FileAccess.Write)
                '构造二进制读取对象 
                br = New IO.BinaryReader(fs)
                '读取线条宽度 
                textBox1.Text = br.ReadSingle().ToString()
                '读取线条颜色 
                button1.ForeColor = Color.FromArgb(br.ReadInt32())
                '清除内容 
                pointList.Clear()
                '读取点的数目 
                Dim count As Integer = br.ReadInt32()
                For i As Integer = 0 To count - 1
                    '读取点的坐标，构造新的Point对象，并加入到pointList中 
                    pointList.Add(New Point(br.ReadInt32(), br.ReadInt32()))
                Next
                '刷新窗口 
                Me.Invalidate(Me.ClientRectangle)
            Catch excep As Exception
                MessageBox.Show(excep.Message, "出错", MessageBoxButtons.OK, MessageBoxIcon.[Error])
            Finally
                '关闭流 
                br.Close()
                fs.Close()
            End Try
        End If
    End Sub
End Class