主题：遍历所有控件，清空控件的内容

 遍历 panel 容器里面的控件

For Each c As Object In e.Form.controls("panel1").children
   
    If typeof c Is winform.TextBox OrElse typeof c Is winform.DateTimePicker  Then
       
        c.text = Nothing
       
    End If
   
Next

For Each c As Object In e.Form.controls("SplitContainer2").panel1.children

For Each c As Object In e.Form.controls("SplitContainer2").panel2.children