vb.net中的SelectAll之后无法编辑文本框

Question

I have an issue, The thing is I have to allow user to enter numeric value in text box up to one decimal point,

When all text selected and I try try to edit text by entering any numeric key, It wont let it change.

Here is the text box with value.

The code behind, Keypress

Private Sub TextBox1_KeyPress(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
    If Regex.IsMatch(TextBox1.Text, "\.\d") Then
        e.Handled = True
    End If
End Sub

Kindly anybody help or suggest better way.

I have added this code but I am unable to restrict user not to enter more then one decimal point value.

 If Not ((Asc(e.KeyChar) >= 48 And Asc(e.KeyChar) <= 57) Or Asc(e.KeyChar) = 46 Or Asc(e.KeyChar) = 8 Or Asc(e.KeyChar) = 127) Then
        e.KeyChar = ""
        e.Handled = False
    End If

Answer 1

Try this: (not regex tho), but works great for numerics.

It allows for 1 x negative symbol, one fullstop (point), using backspace, and any numerics..

       Private Sub priceTextBox_KeyPress(sender As Object, e As KeyPressEventArgs) Handles priceTextBox.KeyPress
       If IsNumeric(e.KeyChar.ToString) = False Then

            If e.KeyChar.ToString = "." And priceTextBox.Text.Contains(".") Then e.Handled = True
            If e.KeyChar.ToString = "-" And priceTextBox.Text.Contains("-") Then e.Handled = True

            If e.KeyChar.ToString <> "." Then
                If e.KeyChar <> ControlChars.Back Then
                    If e.KeyChar <> "-" Then
                        e.Handled = True
                    End If
                End If
            End If
        End If
        End Sub

EDIT

This allows for the above numerics, as well as only 1 decimal point. I kept it simple with more code lines to show steps, so you can see what actually happens. I am sure it can be improved, this is a quick and dirty version...

• Allows for Globalization of the decimal character

• Also catches a "paste" into the textbox, that normally circumvents the keypress catch routines

   Dim lastProperText As String = "" Private Sub priceTextBox_TextChanged(sender As Object, e As EventArgs) Handles priceTextBox.TextChanged If priceTextBox.Text = "" Then Exit Sub If IsNumeric(priceTextBox.Text) = False Then priceTextBox.Text = lastProperText If _containsDecimal(priceTextBox.Text, 2) = True Then priceTextBox.Text = lastProperText End Sub Private Sub priceTextBox_KeyPress(sender As Object, e As KeyPressEventArgs) Handles priceTextBox.KeyPress Dim decimalSeparator As String = Globalization.CultureInfo.CurrentCulture.NumberFormat.NumberDecimalSeparator If IsNumeric(e.KeyChar.ToString) = False Then If e.KeyChar.ToString = decimalSeparator And priceTextBox.Text.Contains(decimalSeparator) Then e.Handled = True If e.KeyChar.ToString = "-" And priceTextBox.Text.Contains("-") Then e.Handled = True 'allow backspace here If e.KeyChar = ControlChars.Back Then Exit Sub If e.KeyChar.ToString <> decimalSeparator Then If e.KeyChar <> ControlChars.Back Then If e.KeyChar <> "-" Then e.Handled = True End If End If End If End If 'BUG FIX If priceTextBox.SelectionStart > priceTextBox.Text.Length - 2 Then If _containsDecimal(priceTextBox.Text, 1) = True Then e.Handled = True End If '/BUG FIX 'keep last good format.. we will use this in case something gets apsted in that does not meet our format... lastProperText = priceTextBox.Text End Sub Private Function _containsDecimal(stringtoCheck As String, decimalNumber As Integer) As Boolean Dim decimalSeparator As String = Globalization.CultureInfo.CurrentCulture.NumberFormat.NumberDecimalSeparator 'check to allow only 1 decimal point Dim positionOfPoint As Integer = 0 'get position of decimal point (.) positionOfPoint = InStr(stringtoCheck, decimalSeparator) 'check if there are not characters after decimal point... 'if nothin after decimal point, allow this keypress, 'if there is already something after decimal point, escape this keypress 'get length of string after "." Dim stringTail As String = "" If Not positionOfPoint = 0 Then stringTail = Mid(stringtoCheck, positionOfPoint) If stringTail.Length > decimalNumber Then Return True End If End If End Function 

Answer 2

I have tried this code:

Works Fine Now.. One Digit after decimal point, you may add \\d\\d to add digits in Regex

 Private Sub TextBox1_KeyPress(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
    If TextBox1.SelectedText.Length = TextBox1.Text.Length Then
        TextBox1.Clear()
    End If
    If Char.IsDigit(e.KeyChar) = True OrElse Char.IsControl(e.KeyChar) = True OrElse e.KeyChar = "."c Then
        If Regex.IsMatch(TextBox1.Text, "\.\d") Then
            'This makes backspace working
            If e.KeyChar = CChar(ChrW(8)) Then
            Else
                e.Handled = True
            End If
        End If
    Else
        e.Handled = True
    End If

End Sub