textbox的一点有关问题!

textbox的一点问题!!!
怎么控制textbox只能输入英文和数字的半角???
请高手指点阿???

------解决方案--------------------
Private Sub TextBox3_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox3.KeyPress
If Asc(e.KeyChar) < 48 Or Asc(e.KeyChar) > 57 Then '0-9
e.Handled = True
End If
End Sub
------解决方案--------------------
me.textbox1.ImeMode=Windows.Forms.ImeMode.Disable
------解决方案--------------------
Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox3.KeyPress
e.Handled = Not Regex.IsMatch(e.KeyChar, "[a-z1-9] ")
End Sub