如何将文本框输入仅过滤为数字?

有很多方法可以做到这一点。我快速尝试了一下,然后选择了这个有效的方法。我使用了文本框的KeyPress子项,并将每个按键传递给IsNumber函数。

注意:我允许使用退格键,以防您在数字上出错并想要删除。

拿出 如果e.KeyChar<>ChrW(按键返回)然后/结束如果 如果你不需要退格,就退一步。

    Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
    If e.KeyChar <> ChrW(Keys.Back) Then
        If Char.IsNumber(e.KeyChar) Then
        Else
            e.Handled = True
        End If
    End If
End Sub

你可以检查Char。IsDigit(e.KeyChar),但在这种情况下最好的办法是创建TextBox的子类并重写IsInputChar()。这样你就有了一个可重用的TextBox控件,你可以把它放在任何地方,这样你就不必重新实现逻辑。

(我的VB有点生疏…)

Public Class NumericTextBox : Inherits TextBox

    Protected Overrides Function IsInputChar(Byval charCode As Char) As Boolean
        If (Char.IsControl(charCode) Or Char.IsDigit(charCode)) Then
            Return MyBase.IsInputChar(charCode)
        Else
            Return False
        End If
    End Function

End Class

文本框 仅接受 数值 和 语句结束 当您不想接受退格键时,代码中的值。增强版

Private Sub TextBox_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress, TextBox2.KeyPress, TextBox3.KeyPress
    If e.KeyChar <> ChrW(Keys.Back) Then
        If Char.IsNumber(e.KeyChar) Then
        Else
            e.Handled = True
        End If
    End If
End Sub

会帮助你的。..

    Public Function IsNumericTextbox(ByVal sender As TextBox, ByVal KeyChar As Char) As Boolean
    'set TRUE: cause a exception when the keychar is not Allowed into vars: allowedChars, allowedOneChar, allowedExceptionChar
    Dim UseThrowDebuggy As Boolean = False

    Dim allowedChars As String = "0123456789"
    Dim allowedOnceChar As Char() = {"."}
    Dim allowedExceptionChar As Keys() = {Keys.Back}

    Dim idxAllowedNotFound As Integer
    Dim idxCountOne As Integer = 0

    idxAllowedNotFound = allowedChars.IndexOf(KeyChar)
    If idxAllowedNotFound = True Then
        'AllowedOnce
        For Each _c As Char In allowedOnceChar
            If _c = KeyChar Then
                'Count Check
                For Each _cc As Char In sender.Text
                    If _c = _cc Then idxCountOne += 1
                Next
                If idxCountOne = 0 Then
                    Return False
                Else
                    Return True
                End If
            End If
        Next
        'Exceptions
        For i As Integer = 0 To allowedExceptionChar.Count - 1
            If Asc(KeyChar) = Convert.ToUInt32(allowedExceptionChar(i)) Then Return False
        Next
        'Not Throw
        If UseThrowDebuggy = False Then
            If Char.IsNumber(KeyChar) Then
                Return False
            Else
                Return True
            End If
        End If
        'Outside to end for throw
    Else
        'AllowedChars
        Return False
    End If

    Dim _kc As String = ControlChars.NewLine & "Char: " & KeyChar & ControlChars.NewLine & "Asc: " & Asc(KeyChar) & ControlChars.NewLine
    Throw New Exception("UseThrowDebuggy found a unknow KeyChar: " & _kc)
End Function

e.已处理=IsNumericTextbox(发送者,e.KeyChar)

 Public Class NumericTextBox : Inherits System.Windows.Forms.TextBox

 Protected Overrides Sub OnKeyPress(e As Windows.Forms.KeyPressEventArgs)
      If Char.IsDigit(e.KeyChar) Or
          Char.IsControl(e.KeyChar) Or
          e.KeyChar = lobalization.CultureInfo.CurrentCulture.NumberFormat.CurrencyDecimalSeparator Then
      MyBase.OnKeyPress(e)
    Else
        e.Handled = True
    End If
 End Sub

 End Class

我建议你使用正则表达式。你可以在谷歌上搜索,比如“仅限正则表达式文本框的数字”,我想你会想出很多例子。

例如,如果你在ASP。NET,你可以这样做:

<asp:TextBox 
    ID="txtPhoneNumber" 
    runat="server" 
    Text='<%#Bind("phoneNumber") %>' 
    MaxLength="15">
</asp:TextBox>

<asp:RegularExpressionValidator 
    ID="rfvUSerPhoneNumberValidate" 
    runat="server"
    ControlToValidate="txtPhoneNumber" 
    Display="Dynamic" 
    ValidationExpression="^[0-9]{1,15}$"
    ErrorMessage="Please enter only numeric value for Phone Number" 
    EnableViewState="true">
</asp:RegularExpressionValidator>

这将允许数字输入,Backspace用于更正您的输入,以及小数点。

    If (e.KeyChar < "0" OrElse e.KeyChar > "9") AndAlso e.KeyChar <> ControlChars.Back AndAlso e.KeyChar <> ControlChars.Cr AndAlso e.KeyChar <> "." Then
        Beep()
        e.Handled = True
    End If

这是限制文本框中数字输入的另一种方法。使用KEYPRESS事件

如果Asc(e.KeyChar)<>13 And Also Asc(e.KeyChar)<>8也不是数字(e.KeyChar)然后 MessageBox。显示(“仅数字”) e.已处理=真 语句结束 结束子

您的功能的目的可以帮助提供其他解决方案。检查每个按键上的数值可能有点过头了。然后,你必须通过考虑退格、删除、复制、粘贴等来夸大它。