form1.vb

苏金明编写的《用VB.NET和VC#.NET开发交互式CAD系统》一书的源代码

Imports System.Runtime.InteropServices
Imports System.Math

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。
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        '
        'Form1
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(6, 14)
        Me.BackColor = System.Drawing.Color.White
        Me.ClientSize = New System.Drawing.Size(440, 366)
        Me.Name = "Form1"
        Me.Text = "Form1"

    End Sub

#End Region

    Private m_StartX, m_StartY, m_EndX, m_EndY As Single
    Private m_Step As Integer = 0
    Private lines As New ArrayList()

    Protected Overrides Sub OnMouseDown(ByVal e As Windows.Forms.MouseEventArgs)
        Dim g As Graphics = Me.CreateGraphics()
        m_Step += 1
        If m_Step = 1 Then
            m_StartX = e.X
            m_StartY = e.Y
            m_EndX = e.X
            m_EndY = e.Y
        ElseIf m_Step = 2 Then
            Dim newline As New CLine(New PointF(m_StartX, m_StartY), _
                    New PointF(e.X, e.Y))
            newline.Draw(g)
            lines.Add(newline)
            m_Step = 0
        End If
    End Sub

    Protected Overrides Sub OnMouseMove(ByVal e As Windows.Forms.MouseEventArgs)
        Dim g As Graphics = Me.CreateGraphics()
        Dim prex, prey As Single
        Dim minX, minY, maxX, maxY As Single
        If m_Step = 1 Then
            prex = m_EndX
            prey = m_EndY
            minX = Min(m_StartX, m_EndX)
            minY = Min(m_StartY, m_EndY)
            maxX = Max(m_StartX, m_EndX)
            maxY = Max(m_StartY, m_EndY)
            Me.Invalidate(New Rectangle(minX, minY, Abs(m_EndX - m_StartX) + 1, _
                    Abs(m_EndY - m_StartY) + 1))
            Me.Update()
            Dim tempLine As New CLine(New PointF(m_StartX, m_StartY), _
                    New PointF(e.X, e.Y))
            tempLine.Draw(g)
            m_EndX = e.X
            m_EndY = e.Y
        End If
    End Sub

    Protected Overrides Sub OnPaint(ByVal e As Windows.Forms.PaintEventArgs)
        Dim g As Graphics = e.Graphics
        g.FillRectangle(Brushes.White, Me.ClientRectangle)
        Dim i As Integer
        For i = 0 To lines.Count - 1
            lines(i).Draw(g)
        Next
    End Sub

End Class