Public Class Form1
    Inherits System.Windows.Forms.Form

#Region " Windows 窗體設計器生成的代碼 "

    Public Sub New()
        MyBase.New()

        '該調用是 Windows 窗體設計器所必需的。
        InitializeComponent()

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

    End Sub

    '窗體重寫 dispose 以清理組件列表。
    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 窗體設計器所必需的
    Private components As System.ComponentModel.IContainer

    '注意: 以下過程是 Windows 窗體設計器所必需的
    '可以使用 Windows 窗體設計器修改此過程。
    '不要使用代碼編輯器修改它。
    Friend WithEvents Label1 As System.Windows.Forms.Label
    Friend WithEvents TextBox1 As System.Windows.Forms.TextBox
    Friend WithEvents Button1 As System.Windows.Forms.Button
    Friend WithEvents Label2 As System.Windows.Forms.Label
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.Label1 = New System.Windows.Forms.Label
        Me.TextBox1 = New System.Windows.Forms.TextBox
        Me.Button1 = New System.Windows.Forms.Button
        Me.Label2 = New System.Windows.Forms.Label
        Me.SuspendLayout()
        '
        'Label1
        '
        Me.Label1.Location = New System.Drawing.Point(24, 24)
        Me.Label1.Name = "Label1"
        Me.Label1.Size = New System.Drawing.Size(96, 24)
        Me.Label1.TabIndex = 0
        Me.Label1.Text = "請輸入數字"
        '
        'TextBox1
        '
        Me.TextBox1.Location = New System.Drawing.Point(24, 64)
        Me.TextBox1.Name = "TextBox1"
        Me.TextBox1.Size = New System.Drawing.Size(256, 21)
        Me.TextBox1.TabIndex = 1
        Me.TextBox1.Text = ""
        '
        'Button1
        '
        Me.Button1.Location = New System.Drawing.Point(168, 24)
        Me.Button1.Name = "Button1"
        Me.Button1.Size = New System.Drawing.Size(104, 24)
        Me.Button1.TabIndex = 2
        Me.Button1.Text = "點擊"
        '
        'Label2
        '
        Me.Label2.Location = New System.Drawing.Point(32, 104)
        Me.Label2.Name = "Label2"
        Me.Label2.Size = New System.Drawing.Size(240, 144)
        Me.Label2.TabIndex = 3
        '
        'Form1
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(6, 14)
        Me.ClientSize = New System.Drawing.Size(292, 266)
        Me.Controls.Add(Me.Label2)
        Me.Controls.Add(Me.Button1)
        Me.Controls.Add(Me.TextBox1)
        Me.Controls.Add(Me.Label1)
        Me.Name = "Form1"
        Me.Text = "Form1"
        Me.ResumeLayout(False)

    End Sub

#End Region

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim a, b As Double
        Try
            a = Double.Parse(TextBox1.Text)
        Catch ex As System.FormatException
            MessageBox.Show("輸入的不是一個實數")
            Exit Sub
        Catch ex As System.OverflowException
            MessageBox.Show("輸入的值超出Double表示范圍")
            Exit Sub
        End Try
        If a > 3 Or a < 1 Then
            TextBox1.Text = ""
        Else
            Dim rnd As Random
            rnd = New Random
            b = rnd.NextDouble() * 6
            b = Math.Round(b)
            Select Case b
                Case 1
                    TextBox1.Text = "1"
                Case 2
                    TextBox1.Text = "2"
                Case 3
                    TextBox1.Text = "3"
                Case 4
                    TextBox1.Text = "4"
                Case 5
                    TextBox1.Text = "5"
                Case Else
                    TextBox1.Text = "6"

            End Select

        End If
    End Sub
End Class