namespace chuangti1{public partial class Form1 : Form{public Form1(){InitializeComponent();}private void Form1_KeyPress(object sender, KeyPressEventArgs e){if (!(e.KeyChar >= '0') && (e.KeyChar <= '9') || e.KeyChar == 0x8)e.Handled = true;textBox3.Text = Convert.ToString(e.Handled);}private void textBox1_TextChanged(object sender, EventArgs e){}private void textBox3_TextChanged(object sender, EventArgs e){}}為什么沒效果}