validating a textbox

[meena83]

hi, i have to enter a value in a textbox that
should accept only alphabets and not digits
should accept only 4 characters
the first should be caps and the other must be small
--how can i do this .

[gurpreetintown]

To restrict the textbox to these input conditions, impose these validations under the value change event of the textbox.

[Nagendra Singh]

U can use max length property of textbox to resrict number of characters.
use keypress event of text box and manipuate the capital letter.

if the e.KeyAscii > Keys.0 or e.KeyAscii <= Keys.0
don't allow
else
allow and change the capitals by adding + 26 to ascii of small letter

[meena83]

To restrict the textbox to these input conditions, impose these validations under the value change event of the textbox.

hi
but still i cant understand and i didnt find that valuechange event.

[meena83]

U can use max length property of textbox to resrict number of characters.
use keypress event of text box and manipuate the capital letter.

if the e.KeyAscii > Keys.0 or e.KeyAscii <= Keys.0
don't allow
else
allow and change the capitals by adding + 26 to ascii of small letter

hi
thanks for your reply. but still i m not clear.can you send me that coding part

[Nagendra Singh]

   private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
        {
            if (e.KeyChar >= '0' && e.KeyChar <= '9')
            {
                e.KeyChar = (char)Keys.None;
            }
        
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            textBox1.MaxLength = 4;         
      
        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {
            if (textBox1.Text.Length == 1)
            {
                char[] c = textBox1.Text.ToCharArray();
                char[] c1 = c[0].ToString().ToUpper().ToCharArray();
                c[0] = c1[0];
                textBox1.Text = convertCharacterArrayToString(c);
                textBox1.SelectAll();
            }
   
        }

        private string convertCharacterArrayToString(char[] c)
        {
            string str = "";
            foreach (char character in c)
            {
                str = str + character;
            }
            return str;
        }