private System.Windows.Forms.TextBox textBox1;
private string text;
public Form1()
{
text = textBox1.Text;
}
private void textBox1_TextChanged(object sender, System.EventArgs e)
{
int len = text.Length;
if(len < textBox1.Text.Length)
{
int index = textBox1.Text.IndexOf(text);
char c = (textBox1.Text.Remove(index,text.Length))[0];
if(c.CompareTo('0') < 0||c.CompareTo('9') >0)
{
textBox1.Text = text;
textBox1.SelectionStart = text.Length;
}
}
text = textBox1.Text;
}