form1.vb

Source code for VB.NET book - Chapter 4

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 dispose 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 PictureBox1 As System.Windows.Forms.PictureBox
    Friend WithEvents Timer1 As System.Windows.Forms.Timer
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.components = New System.ComponentModel.Container
        Dim resources As System.Resources.ResourceManager = New System.Resources.ResourceManager(GetType(Form1))
        Me.PictureBox1 = New System.Windows.Forms.PictureBox
        Me.Timer1 = New System.Windows.Forms.Timer(Me.components)
        Me.SuspendLayout()
        '
        'PictureBox1
        '
        Me.PictureBox1.Dock = System.Windows.Forms.DockStyle.Fill
        Me.PictureBox1.Image = CType(resources.GetObject("PictureBox1.Image"), System.Drawing.Image)
        Me.PictureBox1.Location = New System.Drawing.Point(0, 0)
        Me.PictureBox1.Name = "PictureBox1"
        Me.PictureBox1.Size = New System.Drawing.Size(292, 266)
        Me.PictureBox1.TabIndex = 0
        Me.PictureBox1.TabStop = False
        '
        'Timer1
        '
        Me.Timer1.Enabled = True
        Me.Timer1.Interval = 10
        '
        'Form1
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.ClientSize = New System.Drawing.Size(292, 266)
        Me.Controls.Add(Me.PictureBox1)
        Me.Name = "Form1"
        Me.Text = "雪花"
        Me.WindowState = System.Windows.Forms.FormWindowState.Maximized
        Me.ResumeLayout(False)

    End Sub

#End Region
    Dim number, x(), y(), v(), s() As Integer
    Dim t As Random = New Random
    Dim g As System.Drawing.Graphics
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        PictureBox1.Location = Me.Location
        PictureBox1.Size = Me.Size
        PictureBox1.SizeMode = PictureBoxSizeMode.StretchImage
        snow()
    End Sub
    Private Sub snow()
        number = 2000
        ReDim x(number - 1)
        ReDim y(number - 1)
        ReDim v(number - 1)
        ReDim s(number - 1)
        Dim i As Integer
        For i = 0 To number - 1
            Insnow(i)
        Next
    End Sub
    Private Sub Insnow(ByVal i As Integer)
        x(i) = t.Next(0, Me.Width - 1)
        y(i) = t.Next(0, Me.Height * 5 / 7)
        v(i) = t.Next(5, 20)
        s(i) = (t.Next(1, 3) * 100 + t.Next(50, 200)) / 100
    End Sub

    Private Sub PictureBox1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles PictureBox1.Paint
        g = PictureBox1.CreateGraphics
        Dim i As Integer
        For i = 0 To number - 1
            g.FillEllipse(Brushes.White, x(i), y(i), s(i), s(i))
        Next
    End Sub

    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        Dim i As Integer
        For i = 0 To number - 1
            y(i) = y(i) + v(i)
            If y(i) >= Me.Height Then
                Insnow(i)
            End If
        Next
        PictureBox1.Invalidate()
    End Sub
End Class