Format a CPF string?

Question

I have a problem, in an app the user type the CPF, but only the numbers because it is very complicated to create mask on Windows Phone, and this CPF will be 'drawn' in a picture of a card, and to get more pleasant I need to draw it with its normal format, dotted. So how do I turn a string:

xxxxxxxxxxx

In:

xxx.xxx.xxx-xx

Answer 1

I don’t know windows phone, but in pure c# would be like this:

public string teste(string cpf)
        {
            return Convert.ToUInt64(cpf).ToString(@"000\.000\.000\-00");
        }

Answer 2

public string teste(string cpf)
{
    return Convert.ToUInt64(cpf).ToString(@"000\.000\.000\-00");
}

This solution does not work for those who have the CPF started with 2 zeros. To solve this problem, you can use this method:

//000.000.000-00
public string FormatCPF(string sender)
{
    string response = sender.Trim();
    if (response.Length == 11)
    {
        response = response.Insert(9, "-");
        response = response.Insert(6, ".");
        response = response.Insert(3, ".");
    }
    return response;
}

Answer 3

private void txtCNPJ_KeyPress(object sender, KeyPressEventArgs e)
        {
            ComboBox t = sender as ComboBox; // ou text Box
            if (e.KeyChar >= 48 && e.KeyChar <= 57)
            {
                t.SelectionStart = t.Text.Length + 1;

                if (t.Text.Length == 2 || t.Text.Length == 6)
                    t.Text += ".";
                else if (t.Text.Length == 10)
                    t.Text += "/";
                else if (t.Text.Length == 15)
                    t.Text += "-";
                t.SelectionStart = t.Text.Length + 1;
            }
        }

Answer 4

private void maskedTextBox1_Leave(object sender, EventArgs e)
{
    // pode se usar codigo formata ou digitar diretamente na control maskTextBox so remover aspas e @
    maskedTextBox1.Mask = @"000\.000\.000\-00";
}

private void button1_Click(object sender, EventArgs e)
{
    //Criar string em branco
    string Salvarmask = "";

    //usar controle para gerar string
    Salvarmask = maskedTextBox1.Text;

    //para visualizar exemplo string Formatada
    label1.Text = Salvarmask.ToString();
}