Mask for formatting Textbox

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Mask for formatting Textbox

Asked 5 years, 10 months ago

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5

I was practicing coding on a project like Winforms, A question soon arose: How to apply a phone mask on a Textbox. So the first thing that popped into my head was to use the event Keypress of the component.

The logic of the code became simple, follows below...

private void cbTelefone_KeyPress(object sender, KeyPressEventArgs e)
    {
        string numero = Convert.ToString(cbTelefone.Text);

        if (numero.Length <= 10) // Telefone Fixo com DDD
        {
            string numeroTelefoneFixo = Convert.ToString(cbTelefone.Text);
            cbTelefone.Text = String.Format(@"{0:(00)0000-0000}", numeroTelefoneFixo);
        }
        else if (numero.Length == 11) // Celular com DDD
        {
            string numeroTelefoneCelular = Convert.ToString(cbTelefone.Text);
            cbTelefone.Text = String.Format(@"{0:(00)00000-0000}", numeroTelefoneCelular);
        }

The Textbox is not receiving the phone mask. What should I do to solve?

1

Why don’t you use a Maskedtextbox?

– Leandro Angelo

2018/08/22 at 16:31
1

Initially the Maskedtextbox does not have format in the standard phones used in Brazil, so I believe I would have to develop a code similar to this using the Maskedtextbox

– Leonardo

2018/08/22 at 16:36
1

@Leonardo the MaskedTextBox allows you to change the default mask, just put it the same way you are putting in your String.Format.

– João Martins

2018/08/22 at 16:37
1

@Joãomartins, but in any case would have to validate if the number is a mobile (11 digits with DDD) or fixed (10 digits with DDD), so in my view, the code will be the same as what I did using Textbox

– Leonardo

2018/08/22 at 16:42
1

But this type of validation can only do it after the user has finished entering the text, otherwise he will not know which size, if 10 or 11. If it is not possible to notice beforehand if the number will have 10 or 11 digits, I would say that it is not possible to apply a mask...

– João Martins

2018/08/22 at 16:45
1

I changed the event to onLeave, put a Breakpoint in the event, typed 10 numbers ... When I left the component I could see in the result of the variables that the string is not being formatted, that is, it continues with the same value...

– Leonardo

2018/08/22 at 17:02

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1 answer

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by João Martins • **5,597** points · Answer 1 · 2018-08-23T08:31:25+00:00

The problem will be that the String.Format cannot convert a String to a numerical format.

Try converting the phone number that comes from TextBox for a number and then apply the mask:

string AplicarMascaraTelefone(string strNumero)
{
    // por omissão tem 10 ou menos dígitos
    string strMascara = "{0:(00)0000-0000}";
    // converter o texto em número
    long lngNumero = Convert.ToInt64(strNumero);

    if (strNumero.Length == 11)
        strMascara = "{0:(00)00000-0000}";

    return string.Format(strMascara, lngNumero);
}

It should be noted that this method should only be referred to in Leave, will not work properly on KeyPress, as we have discussed in the comments on your question.