VB .Net autofill dash(-) in TextBox

Question

I want to make an output like this in vb. net TextBox.

ex. account number : 01-12-001

If I type 01, it will output 01-, then 01-12 ----> output 01-12-.

On deleting text, ex. deletion of the last 3 character 01-12-001 ----> output 01-12, if will automatic delete the dash (-).

Thank you....

Answer 1

Hi @soLo Lz , You can refer to the following code.

    Private Sub TextBox1_TextChanged(sender As Object, e As EventArgs) Handles TextBox1.TextChanged

        Dim text As String = TextBox1.Text
        Dim cursorPosition As Integer = TextBox1.SelectionStart
        Dim digitsOnly As String = Regex.Replace(text, "\D", "")
        Dim formattedText As String = String.Empty

        If digitsOnly.Length >= 2 AndAlso digitsOnly.Length <= 3 Then
            formattedText = Regex.Replace(digitsOnly, "(.{2})(.+)?", "$1-$2")
        ElseIf digitsOnly.Length >= 4 Then
            formattedText = Regex.Replace(digitsOnly, "(.{2})(.{2})(.+)?", "$1-$2-$3")
        Else
            formattedText = digitsOnly
        End If

        TextBox1.Text = formattedText
        TextBox1.SelectionStart = cursorPosition + 1
    End Sub
    Private Sub TextBox1_KeyDown(sender As Object, e As KeyEventArgs) Handles TextBox1.KeyDown
        If e.KeyCode = Keys.Back Then
            Dim text As String = TextBox1.Text
            Dim cursorPosition As Integer = TextBox1.SelectionStart

            If cursorPosition > 1 AndAlso text(cursorPosition - 2) = "-" Then
                TextBox1.Text = text.Remove(cursorPosition - 2, 2)
                TextBox1.SelectionStart = cursorPosition - 2
                e.SuppressKeyPress = True
            ElseIf cursorPosition = text.Length AndAlso text.EndsWith("-") Then
                TextBox1.Text = text.Remove(text.Length - 1)
                TextBox1.SelectionStart = cursorPosition - 1
                e.SuppressKeyPress = True
            End If
        End If
    End Sub

Best Regards.

Jiachen Li

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