如何允许用户只在vb.net的文本框中输入数字？

Question

如何阻止用户输入字符,但只能输入数字和'.' 在vb.net 2005的文本框中？

Answer 1

以下内容允许您测试特定的键值(来自http://www.daniweb.com/forums/thread127299.html):

Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
    If (Microsoft.VisualBasic.Asc(e.KeyChar) < 48) _
              Or (Microsoft.VisualBasic.Asc(e.KeyChar) > 57) Then
            e.Handled = True
    End If
    If (Microsoft.VisualBasic.Asc(e.KeyChar) = 8) Then
            e.Handled = False
    End If
End Sub

如果这不是您要找的,请尝试该isNumeric()功能.

Answer 2

只是为了帮助,我有一个片段,我正在制作一个可能有用的计算器,它允许删除,退格,数字和'.' 焦炭.您还可以添加对函数的调用,以便在按Enter键时处理文本框.

  Private Sub Box_Input_KeyDown(ByVal sender As Object, _
                                ByVal e As System.Windows.Forms.KeyEventArgs) _
                                Handles Box_Input.KeyDown



    If Char.IsDigit(Chr(e.KeyValue)) Or _
       Chr(e.KeyValue) = "¾"c Or _
       e.KeyData = Keys.Delete Or _
       e.KeyData = Keys.Back Then

        If Chr(e.KeyValue) = "¾"c Then
            If Box_Input.Text.Contains(".") Then
                e.SuppressKeyPress = True
            Else
                e.SuppressKeyPress = False
            End If
        End If
    ElseIf e.KeyData = Keys.Enter Then
         `State a call to function for when Enter is pressed`
    Else
        e.SuppressKeyPress = True
    End If

End Sub

此代码允许输入所有数字,后退空格和删除键以及仅允许一个'.' 在文中.一个想法可能是添加TAB功能以允许Tab停止.