[求助]出现下列错误，找不到原因，请专家指导， - 专家坐堂 - Foxtable(狐表) - 新一代数据库软件，完美融合Access、Foxpro、Excel、vb.net之优势，人人都能掌握的快速软件开发工具!

Dim tian As WinForm.ComboBox = e.Form.Controls("天数")

Dim mss As WinForm.ComboBox = e.Form.Controls("面试室")

Dim wlmc As WinForm.ComboBox = e.Form.Controls("首字母")

If tian.value Is Nothing Or mss.value Is Nothing Then

Tables("号对人_号对人").Filter = "首字母 like '*" & wlmc.Text & "*'"

ElseIf tian.value IsNot Nothing And mss.value Is Nothing Then

Tables("号对人_号对人").Filter = "天数 = '" & tian.Text & "'And 面试序号 Is null And 首字母 Like '*" & wlmc.Text & "*'"

ElseIf tian.value IsNot Nothing And mss.value IsNot Nothing Then

……

或者

Dim tian As WinForm.ComboBox = e.Form.Controls("天数")

Dim mss As WinForm.ComboBox = e.Form.Controls("面试室")

Dim wlmc As WinForm.ComboBox = e.Form.Controls("首字母")

If tian.Text = "" Or mss.Text = "" Then

Tables("号对人_号对人").Filter = "首字母 like '*" & wlmc.Text & "*'"

ElseIf tian.Text > "" And mss.Text = "" Then

Tables("号对人_号对人").Filter = "天数 = '" & tian.Text & "'And 面试序号 Is null And 首字母 Like '*" & wlmc.Text & "*'"

ElseIf tian.Text > "" And mss.Text > "" Then

Tables("号对人_号对人").Filter = "天数 = '" & tian.Text & "' and 面试室 = '" & mss.Text & "'and 面试序号 is null and 首字母 like '*" & wlmc.Text & "*'"

End If

主题：[求助]出现下列错误，找不到原因，请专家指导，