关于combobox的简单问题出错信息为“类型不匹配”

Private Sub Command1_Click()
Dim temp As String
If Trim(Text1.Text) <> "" Then
temp = "trim(text1.text)"
Else
temp = ""
End If
If temp <> "" Then
temp = temp And "trim(text2.text)"
Else
temp = "trim(text2.text)"
End If
If temp <> "" Then
temp = temp And "trim(Combobox.text)"
Else
temp = "trim(Combobox.text)"
End If
If temp <> "" Then
temp = temp And "trim(text3.text)"
Else
temp = "trim(text3.text)"
End If
我的代码如上，但是当程序单步运行到 temp = "trim(Combobox.text)"时出错信息为“类型不匹配”