显示输入问题

Private Sub TextBox1_KeyPress(keyascii As Integer)
If keyascii < 48 Or keyascii > 57 Then keyascii = 0
End Sub
Private Sub TextBox1_TextChanged(sender As System.Object, e As System.EventArgs) Handles TextBox1.TextChanged
End Sub
为何textbox中还能输入其他字符 求大神解救