Eliminating multiple "." or "-" in textbox

[DiverDan]

Im trying to eliminate multiple instances of dot and minus in a textbox. My code is obviously not working but is as follows:

Private Sub tbTemperature_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles tbTemperature.KeyPress
        Dim i, charsInBox As Short
        Dim charactor As String
        charsInBox = Len(tbTemperature.Text)
       If Not AscW(e.KeyChar) <= 47 And Not AscW(e.KeyChar) >= 58 Or AscW(e.KeyChar) = 8 Or AscW(e.KeyChar) = 46 Or Asc(e.KeyChar) = 45 Then
                    For i = 0 To charsInBox - 1
                charactor = tbTemperature.Text.Substring(i, 1)
                If charactor = "." Then e.Handled = True
                If charactor = "-" Then e.Handled = True
            Next
           e.Handled = False
            Else
        e.Handled = True
        End If
    End Sub

How can I eliminate multiple instances of dot and minus?

Thanks

 

[Volte]

Try it like this:

        Dim key As Char = e.KeyChar

        If key = "." Or key = "-" Then
            If TextBox1.Text.IndexOf(key) >= 0 Then
                e.Handled = True
            End If
        End If

Dont forget to check for the characters when you paste as well.

 

[DiverDan]

Thanks VolteFace,

Ive got the paste validation coverd, this was the final touch.

 

[DiverDan]

Opps, this still does not stop multiple instances of dot and minus. I implemented your suggestion as follows:

    Private Sub tbTemperature_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles tbTemperature.KeyPress
        Dim key As Char = e.KeyChar
        If Not AscW(key) <= 47 And Not AscW(key) >= 58 Or AscW(key) = 8 Or AscW(key) = 46 Or Asc(key) = 45 Then
            If key = "." Or key = "-" Then
                If tbTemperature.Text.IndexOf(key) >= 0 Then
                    e.Handled = True
                End If
            End If
            e.Handled = False
        Else
            e.Handled = True
        End If
    End Sub
#End Region

Multiple dots and minuses still occur

 

[a_jam_sandwich]

    Private Sub tbTemperture_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles tbTemperature.KeyPress
        If Not AscW(e.KeyChar) <= 47 And Not AscW(e.KeyChar) >= 58 _
            Or AscW(e.KeyChar) = 8 Or AscW(e.KeyChar) = 46 Or Asc(e.KeyChar) = 45 Then
            If e.KeyChar = "." Then
                If TextBox1.Text.IndexOf(".") = -1 Then e.Handled = False Else e.Handled = True
            ElseIf e.KeyChar = "-" Then
                If TextBox1.Text.IndexOf("-") = -1 Then e.Handled = False Else e.Handled = True
            End If
        Else
            e.Handled = False
        End If
    End Sub

Give that a try

Andy

 

[DiverDan]

Thanks Andy,

Its getting closer by perventing multiple instances of dot and minus, but it does allow letters and not just numbers to be input. But I used your ideas and everything works well now. The modifided code is:

    Private Sub tbTemperture_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles tbTemperature.KeyPress
        If Not AscW(e.KeyChar) <= 47 And Not AscW(e.KeyChar) >= 58 _
            Or AscW(e.KeyChar) = 8 Or AscW(e.KeyChar) = 46 Or Asc(e.KeyChar) = 45 Then
            If e.KeyChar = "." Then
                If tbTemperature.Text.IndexOf(".") = -1 Then
                    e.Handled = False
                Else : e.Handled = True
                    Exit Sub
                End If
            ElseIf e.KeyChar = "-" Then
                If tbTemperature.Text.IndexOf("-") = -1 Then
                    e.Handled = False
                Else : e.Handled = True
                    Exit Sub
                End If
            End If
            e.Handled = False
        Else
            e.Handled = True
        End If
    End Sub

This prevents multiple instances of dot and minus and allows only numbers into the textbox field.

Once again, thanks to Andy and VolteFace

 

[Volte]

Originally posted by DiverDan
Opps, this still does not stop multiple instances of dot and minus. I implemented your suggestion as follows:

    Private Sub tbTemperature_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles tbTemperature.KeyPress
        Dim key As Char = e.KeyChar
        If Not AscW(key) <= 47 And Not AscW(key) >= 58 Or AscW(key) = 8 Or AscW(key) = 46 Or Asc(key) = 45 Then
            If key = "." Or key = "-" Then
                If tbTemperature.Text.IndexOf(key) >= 0 Then
                    e.Handled = True
                End If
            End If
            e.Handled = False
        Else
            e.Handled = True
        End If
    End Sub
#End Region

Multiple dots and minuses still occur

Youre setting e.Handled = True inside the code that I gave you, and then
setting it right back to false afterwards. Take out the e.Handled = False
line before the Else.

 

[DiverDan]

Youre right.

Thanks VolteFace