# signs in ADO locates (Delphi XE5) - delphi

Question

With an TADOQuery.Locate that uses a list of fields and a VarArray of values, if one of the values contains a # sign, we get this exception:
'Arguments are of the wrong type, are out of acceptable range, or are in conflict with one another.'
I've traced this down to ADODB which itself seems to be using # signs as delimiters.
Is there a way to escape #-signs so that the query doesn't fail?
* EDIT 1 *
I was wrong. What causes this failure is a string that has a pound sign and a single quote. The code shown below fails with error message noted above.
What really worries us is that when it fails running as an .exe outside the IDE, there's no runtime exception. We only see the exception when we're in the IDE. If our programmers hadn't happened to be using data that triggers this we never would have known that the .Locate returned FALSE because of a runtime error, not because a matching record was not found.
Code:
var
SearchArray: Variant;
begin
SearchArray := VarArrayCreate([0,1], VarVariant);
SearchArray[0] := 'T#more''wo';
SearchArray[1] := 'One';
ADOQuery.Locate('FieldName1;FieldName2', SearchArray, []);

Answer 1

Please see Updates below; I've found a work-around that's at least worth testing.
Even with Sql Server tables, the # shouldn't need to be escaped.
The following code works correctly in D7..XE8
procedure TForm1.Button1Click(Sender: TObject);
begin
AdoQuery1.Locate('country;class', VarArrayOf(['GB', Edit1.Text]), []);
end;
when Edit1.Text contains 'D#E', so I think your problem must lie elsewhere. Try a minimalist project with just that code, after rebooting your machine.
Update: As noted in a comment, there is a problem with .Locate where the expression
passed to GetFilterStr (in ADODB.Pas) contains a # followed by a single quote. To try and
work out a work-around for this, I've transplanted GetFilterStr into my code and have
been experimenting with using it to construct a recordset filter on my AdoQuery, as I noticed
that this is what .Locate does in the statement
FLookupCursor.Filter := LocateFilter;
The code I'm using for this, including my "corrected" version of GetFilterStr, is below.
What I haven't managed to figure out yet is how to avoid getting an exception on
AdoQuery1.Recordset.Filter := S;
when the filter expression yields no records.
(Btw, for convenience, I'm doing this in D7, but using XE8's GetFilterStr, which is why I've had to comment out the reference to ftFixedWideChar)
function GetFilterStr(Field: TField; Value: Variant; Partial: Boolean = False): WideString;
// From XE8 Data.Win.ADODB
var
Operator,
FieldName,
QuoteCh: WideString;
begin
QuoteCh := '';
Operator := '=';
FieldName := Field.FieldName;
if Pos(' ', FieldName) > 0 then
FieldName := WideFormat('[%s]', [FieldName]);
if VarIsNull(Value) or VarIsClear(Value) then
Value := 'Null'
else
case Field.DataType of
ftDate, ftTime, ftDateTime:
QuoteCh := '#';
ftString, ftFixedChar, ftWideString://, ftFixedWideChar:
begin
if Partial and (Value <> '') then
begin
Value := Value + '*';
Operator := ' like '; { Do not localize }
end;
{.$define UseOriginal}
{$ifdef UseOriginal}
if Pos('''', Value) > 0 then
QuoteCh := '#' else
QuoteCh := '''';
{$else}
QuoteCh := '''';
if Pos('''', Value) > 0 then begin
QuoteCh := '';
Value := QuotedStr(Value);
end;
{$endif}
end;
end;
Result := WideFormat('(%s%s%s%s%2:s)', [FieldName, Operator, QuoteCh, VarToWideStr(Value)]);
end;
procedure TForm1.CreateFilterExpr;
var
S : String;
begin
// clear any existing filter
AdoQuery1.Recordset.Filter := adFilterNone;
AdoQuery1.Refresh;
if edFilter.Text = '' then Exit;
S := GetFilterStr(AdoQuery1.FieldByName('Applicant'), edFilter.Text, cbPartialKey.Checked);
// Add the filter expr to Memo1 so we can inspect it
Memo1.Lines.Add(S);
try
AdoQuery1.Recordset.Filter := S;
AdoQuery1.Refresh;
except
end;
end;
procedure TForm1.FilterClick(Sender: TObject);
begin
CreateFilterExpr;
end;
Update 2: Try the following:
Copy Data.Win.ADODB.Pas to your project directory
In it, replace GetFilterExpr by the version above, making sure that UseOriginal
isn't DEFINEd, and that ftFixedWideChar is reinstated in the Case statement.
Build and run your project
In XE8 at any rate, my testbed now correctly Locate()s a field ending with ' or #'
(or containing either of them if loPartialKey is specified. (I can't test in XE4/5
because my XE4 now says it's unlicenced since I upgraded to Win10 last week, thanks EMBA!)
I hestitate to call this a solution or even a work-around as yet, but it is at least worth testing.
I'm not sure whether I'd call the original version of GetFilterExpr bugged, because I'm not sure
what use-case its treatment of values containing quotes was intended to handle.