主题：清空框

Dim aa As WinForm.DateTimePicker = e.Form.Controls("起始日期")
Dim bb As WinForm.DateTimePicker = e.Form.Controls("终止日期")
Dim cc As WinForm.TextBox = e.Form.Controls("收购头数")
Dim dd As WinForm.TextBox = e.Form.Controls("收购重量")
Dim ee As WinForm.ComboBox = e.Form.Controls("收购金额")
Dim ff As WinForm.TextBox = e.Form.Controls("销售头数")
Dim gg As WinForm.TextBox = e.Form.Controls("销售重量")
Dim hh As WinForm.TextBox = e.Form.Controls("销售金额")
aa.Text=""
bb.Text=""
cc.Text=""
dd.text=""
ee.Text=""
ff.Text=""
gg.Text=""
hh.text=""

运行错误：Unable to cast object of type 'Foxtable.WinForm.TextBox' to type 'Foxtable.WinForm.ComboBox'.

真是马虎！对不起！

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