Textbox validation for amount

Question

I want to check a textbox value where value have to positive or negative.. negative input value should -10.25 -0.20-6 etc these patern. and also positive input value should 1.25 0.50 5 etc these patarn. I want to validate onKeyPress Event..

Manas Mohapatra · Answer

Did you try like this: You nned to attach an keypress event in textbox properties. http://csharp.net-informations.com/gui/key-press-cs.htm private void textBox1_KeyPress( object sender KeyPressEventArgs e) { if (! char .IsControl(e.KeyChar) && (! char .IsDigit(e.KeyChar)) && (e.KeyChar != '.' ) && (e.KeyChar != '-' )) e.Handled = true ; // only allow one decimal point if (e.KeyChar == '.' && (sender as TextBox).Text.IndexOf( '.' ) > -1) e.Handled = true ; // only allow minus sign at the beginning if (e.KeyChar == '-' && (sender as TextBox).Text.Length > 0) e.Handled = true ; if (e.KeyChar == 13 || e.KeyChar == ( char )Keys.Enter) { try { double myDouble = double .parse(TextBox1.Text) } catch (Exception e) { MessageBox.Show( Input is incorrect  Error ); // make textBox1 blank and red as border.. TextBox1.Text =  ; } } // OR try like this var regex = new Regex( ^[-]?\d+(\.\d+)?$  RegexOptions.Compiled); Match m = regex.Match(TextBox1.Text + e.KeyChar); if (!m.Success) { MessageBox.Show( Input is incorrect  Error ); } }