using System.Windows.Forms;

namespace PaintDotNet.CustomControl
{
    public partial class UserTextBox : TextBox
    {
        /// <summary>
        /// 允许输入正整数的textbox
        /// 如有其它需要，可以再此基础上扩展或者独立创建也可以
        /// </summary>
        public UserTextBox()
        {
            this.KeyPress += new KeyPressEventHandler(TextBoxFoucs_KeyPress);
        }

        private void TextBoxFoucs_KeyPress(object sender, KeyPressEventArgs e)
        {
            if (e.KeyChar != '\b')//这是允许输入退格键 
            {
                int len = this.Text.Length;
                if (len < 1 && e.KeyChar == '0')
                {
                    e.Handled = true;
                }
                else if ((e.KeyChar < '0') || (e.KeyChar > '9'))//这是允许输入0-9数字 
                {
                    e.Handled = true;
                }
            }
        }
    }
}