兩段代碼 老師給的

給一個文本框，只能輸入數字、小數點和負號，其他的按鍵輸入將不顯示。

 

1.普通程序代碼控制

Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
        Dim c As Char
        c = e.KeyChar
        If c = "."c Then
            If InStr(TextBox1.Text, e.KeyChar) > 0 Or (InStr(TextBox1.Text, "-") > 0) And (TextBox1.SelectionStart = 0) Then
                e.KeyChar = ""
            End If
        ElseIf c = "-"c Then
            If InStr(TextBox1.Text, c) > 0 Or TextBox1.SelectionStart > 0 Then
                e.KeyChar = ""
            End If
        ElseIf c = "0"c Then
            If (TextBox1.SelectionStart = 0 And Not TextBox1.Text.StartsWith("0") And TextBox1.Text.Length <> 0) Or (TextBox1.SelectionStart <= 1 And TextBox1.Text.StartsWith("0")) Then
                e.KeyChar = ""
            End If
        ElseIf c = ControlChars.Back Then
        ElseIf InStr("123456789", e.KeyChar) <= 0 Then
            e.KeyChar = ""
        End If
    End Sub

 

2.正則表達式控制//正則表達式不對

    Private Sub TextBox2_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox2.KeyPress
        '利用正則表達式驗證
        'System.Text.RegularExpressions.Regex.IsMatch(TextBox2.Text, "^(-?\\d+)(\\.\\d+)?$")    ''''該表達式來源與網上，未經證實
    End Sub

//  ^[+-]?(?:\d+\.?\d*|\d*\.?\d+)[\r\n]*$  據說這個是對的。未驗證。

 

3.使用MaskedTextBox//不能輸入-和。

Mask屬性設置的是自定義掩碼爲999999999999999

 

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將窗體中所有TextBox的text全部清空，其他的CheckBox啊RadioButton啊這些照舊

Private Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim tp As TabPage
        Dim text As Control

        For Each tp In TabControl1.TabPages
            For Each text In tp.Controls
                If TypeOf text Is TextBox Then
                    text.Text = ""
                End If
            Next
        Next

    End Sub