主题：这行代码要怎么改?请教老师

Dim kd As Double = val(e.Sender.Text)
If IsNumeric(e.Sender.Text) Then
    If kd > 0 Then
        e.Form.Controls("CheckBox1").Checked = False
        e.Form.Controls("CheckBox2").Checked = False
        e.Form.Controls("CheckBox3").Checked = False
    Else
        '''相应的判断

    End If
Else
    e.Sender.Value = ""
    e.Sender.Select()
    Return
End If