Question

我正在尝试将正则表达式添加到下面的代码中，以确保只接受数字。代码非常基础，它计算正方形的面积并将结果放在RichTextBox.Text中我正在使用VB Visual Studio 2012.任何帮助将不胜感激。

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Public Class SquareArea
    Inherits ShapeArea
    Public Overrides Function Area() As Double
        Return (Me.Lengh ^ 2)
    End Function
End Class

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Public Class Square

    Private Sub Square_Load(sender As Object, e As EventArgs) Handles MyBase.Load

    End Sub

    Private Sub ResultButton_Click(sender As Object, e As EventArgs) Handles ResultButton.Click
        Dim area = New SquareArea
        area.Lengh = SideTextBox.Text
        ResultRichTextBox.Text = area.Area()
    End Sub

    Private Sub CloseSquareButton_Click(sender As Object, e As EventArgs) Handles CloseSquareButton.Click
        Me.Close()
    End Sub
End Class

Answer 1

有几种方法可以做到这一点。但最好的方法是使用SideTextBox文本框的验证事件。

Private Sub SideTextBox_Validating  (ByVal sender As System.Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles txtSideTextBox.Validating
'your code here
End Sub

或您还可以使用其KeyPress事件，以便在用户输入非数字字符时提示用户。

Private Sub SideTextBox_KeyPress (ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles txtSideTextBox.KeyPress
'your code here
End Sub

Answer 2

使用此代码...

Private Sub txtValue_KeyPress(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles txtValue.KeyPress

        If Char.IsDigit(e.KeyChar) = False And Char.IsControl(e.KeyChar) = False Then
            e.Handled = True
        End If
    End Sub

Answer 3

我通常不会在Visual Basic中编写，但您希望将RegularExpression作为类成员（System.Text.RegularExpressions命名空间）添加到您的类中。下面显示的正则表达式模式仅允许数字。在正则表达式上调用Match方法会返回一个Match类，您可以将其称为Success on以获得布尔结果（true / false）

您可能需要稍作修改，因为我通常不会用VB编写，但表达式和类是正确的

'Declare Regular Expression Class, Compile once    
Dim RegularExpression regex As RegularExpression = New RegularExpression("^[0-9]*$", RegExOptions.Compile)
    Private Sub Square_Load(sender As Object, e As EventArgs) Handles MyBase.Load

    End Sub

    Private Sub ResultButton_Click(sender As Object, e As EventArgs) Handles ResultButton.Click
        Dim area = New SquareArea
    ' Insert Magic Here
    If regex.Match(SideTextBox.Text).Success=False Then
        MessageBox.Show("Invalid entry")
        Return
    End If
        area.Lengh = SideTextBox.Text
        ResultRichTe...

    Private Sub CloseSquareButton_Click(sender As Object, e As EventArgs) Handles CloseSquareButton.Click
        Me.Close()
    End Sub
    End Class

在何处添加正则表达式的代码以确保只接受数字

3 个答案: