Correctly assigned parameter valuecan not be used

问题

I want to get a cmb-value before the entry is changed, by using ".oldValue". The value is correctly assigned (according to debugger), but running the SQL Access is asking for a manual entry. Doing the entry manually works fine, so the remaining code should be fine.

My Code:

Dim CategoryNameBeforeChange As String

CategoryNameBeforeChange = Forms!frmCategory!txtCategoryName.OldValue

SQL = "UPDATE CategoryTbl " & _
"SET CategoryTbl.CategoryName = Forms!frmCategory!txtCategoryName " & _
"WHERE (CategoryTbl.CategoryName = CategoryNameBeforeChange);"

Any idea what went wrong here?

Any help is greatly appreciated!

回答1:

Try this:

SQL = "UPDATE CategoryTbl " & _
"SET CategoryTbl.CategoryName = Forms!frmCategory!txtCategoryName " & _
"WHERE (CategoryTbl.CategoryName = " & CategoryNameBeforeChange & ");"

I suspect that CategoryName is text, in this case it should be

SQL = "UPDATE CategoryTbl " & _
"SET CategoryTbl.CategoryName = Forms!frmCategory!txtCategoryName " & _
"WHERE (CategoryTbl.CategoryName = '" & CategoryNameBeforeChange & "');"

来源：https://stackoverflow.com/questions/48949153/correctly-assigned-parameter-valuecan-not-be-used