Question

I m Working On A windows Form.. I Need my TextBox Not To Accept negative Values ..How Can I Do this..
IS There Any Property Availiable For Doing The same…

Answer 1

You need to write keypress event of textbox like :

private void textBox1_KeyPress(object sender, KeyPressEventArgs e) 
{ 
    if (!char.IsControl(e.KeyChar) && !char.IsDigit(e.KeyChar))
    { 
        e.Handled = true; 
    } 
} 

You can also user numeric updown control to prevent negetive values.

UPDATE :

Ref: Sai Kalyan Akshinthala

My code will not handle the case of copy/paste. User can enter negative values by copy/paste. So I think Sai Kalyan Akshinthala’s answer is correct for that case except one small change of Length >= 2.

private void textBox1_TextChanged(object sender, EventArgs e)
{
    if(textBox1.Text.Length >= 2)     
    {     
        int acceptednumber = Convert.ToInt32(textBox1.Text);     
        if(acceptednumber < 0)     
        {     
            textBox1.Text = "";     
            MessageBox.Show("-ve values are not allowed");     
        }     
        else     
        {     
            textBox1.Text = textBox1.Text;     
        }     
    }  
}