Question

I am building this C# windows application. On a certain Form, I am using maskedtextbox to enter upto 3 numerical digits, then I convert it into int as I have to send all these data to database with an insert query, but the problem is that these maskedtextboxes give error when left empty:

int scd_user_comm = Convert.ToInt32(maskedTextBox1.Text);

and the error is :

Input string was not in a correct format.

The corresponding field in database allows null, so if left empty, it must not give an error. Can anyone help please?

One side question:: Can I use a textbox or maskedtextbox to ensure that user only enters numeric value b/w 0 to 100? Thanks in advance.

Answer 1

You could try the Int32.TryParse() method

int scd_user_comm;
if(Int32.TryParse(maskedTextBox1.Text, out scd_user_comm) == false)
     scd_user_comm = 0;

this will give you all the flexiblity required to work with your integer var and your maschedTextBox-

To force your maskTextBox to accept only numeric values set

   maskTextBox1.Mask = "999";
   maskTextBox1.TextMaskFormat = MaskFormat.ExludePromptAndLiterals;

However this is not enough to ensure the enterd number is between 0 and 100.
To get this result you need to use the Validating event and reject the input if is outside your limits

    private void maskedTextBox1_Validating(object sender, CancelEventArgs e)
    {
        int num;
        if (Int32.TryParse(maskedTextBox1.Text, out num) == true) 
        {
            if (num < 0 || num > 100)
            {
                MessageBox.Show("Insert number between 0 and 100");
                e.Cancel = true;
            }
        }
    }