[DUG] Searching ClientDataSet using locate

[Stephen Barker]

Hi John,

Are you trying to locate the same string within multiple fields? If so, I
don't think the locate will help you there.

Try using the onfilterrecord event as Neven said, or a filter expression
like this if your database allows it:

.filter := 'name like ''%'+findstr+'%'' or address1 like ''%'+findstr+'%''
or...

or even do a brute force scan of all records in code.


hth
Steve 

> -----Original Message-----
> From: John Bird [mailto:johnkbird at paradise.net.nz] 
> Sent: Thursday, 6 November 2008 6:13 p.m.
> To: NZ Borland Developers Group - Delphi List
> Subject: Re: [DUG] Searching ClientDataSet using locate
> 
> Yes that would work for searching two fields, but do I do "n" 
> fields - ie
> what I am trying to do is generalise and build a list of 
> fields to search
> for at runtime where the number of fields to search changes
> 
> (ie all where Datatype = ftString) - I can build a string 
> listing the wanted
> string fields, and this goes in the first parameter ok.
> 
> What I have not figured yet is how to build the second 
> parameter when I am
> searching in an arbitrary number of fields  I am using the same search
> string  on all the fields,  (it has to be passed as a variant 
> array with as
> many entries as the number of fields being searched if I understand
> correctly).
> 
> I have tried something like
> 
> Findstr:  String;                        //string to find in 
> the dataset
> AlphaFieldsList: String;           //fields list of all 
> string fields, eg
> 'Name;Address1;Address2;Description'
>                                              //this is built 
> at runtime by
> looking at the dataset
> vAlphaStringsList:variant;
> AlphaFieldsAmx: iinteger;        //This is set to the number of string
> fields found in this dataset
> 
>                 ...
> 
>   if AlphaFieldsamx >=0 then
>  begin
>    vAlphaStringsList := VarArrayCreate([0, AlphaFieldsAmx],  
> varVariant);
>    for i := 0 to AlphaFieldsAmx do
>    begin
>        cAlphaStringsList[i] := Findstr;
>    end;
> 
> 
>   cdsFind.locate(AlphaFieldsList, vAlphaStringsList, [loPartialKey,
> loCaseInsensitive])
> 
> I suspect I am doing something wrong building the variant 
> parameter and I am
> new to working with variants...
> 
> But it don't seem to work.....any suggestions how to build the second
> parameter?
> 
> I have thought of doing the search by filtering, but some of 
> the datasets I
> want to search on are already filtered which makes it harder 
> to use filters
> for new functions..
> 
> John
> >
> > .Locate('Field1;Field1', VarArrayOf([Variable1, Variable2])
> >
> > Works fine for me (all over the place but just with std TDataset)
> 
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