[分享]今天想了一个方法对付 Lookup字段的"未知错误"

在ADODB中的function TCustomADODataSet.LocateRecord,找到FLookupCursor.Find,作如下改动...
    {我添加的......
     在编辑记录集时,只要Lookup的字段为Null,就很容易出现"未知错误",但这个错误在IDE外看不见,
     调试时觉得很烦,干脆就...
    }
          if VarIsNull(KeyValues) then                      //我添加的......
            FLookupCursor.Find(GetFilterStr(FieldByName(KeyFields), -10000, Partial), 0,  //我添加的......
             adSearchForward, EmptyParam)                               //我添加的......
          else                                                         //我添加的......
            FLookupCursor.Find(GetFilterStr(FieldByName(KeyFields), KeyValues, Partial), 0,
             adSearchForward, EmptyParam)