Question

I have a winform where I have a textbox that will take upto 14 numbers. Now if user enters less that 14 i have to populate the rest of the fields with 0s. Eg. if a user 10 numbers the i have to include 4 more 0’s to to make it 14.

Answer 1

Change the MaxLength property of the text box to 14. After you get the Text property, use, the PadLeft, or PadRight methods on the String class.

Example

void textBox_LostFocus(object sender, EventArgs e)
{
    var text = this.textBox.Text;
    text = text.PadLeft(14, '0');

    this.textBox.Text = text;
}

Results

var value = "abcd";
var leftPadded = value.PadLeft(14, '0'); // <- "0000000000abcd"
var rightPadded = value.PadRight(14, '0'); // <- "abcd0000000000"

You might also want to consider using the MaskedTextBox class.