TFieldDefs without TDataSet?
lazarus / 5-Lazarus Extra Components

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ericisko · 2008-10-16 22:52

In FPC 2.2.0, I was able to do:

FieldDefs := TFieldDefs.Create(nil);
FieldDefs.Assign(MyQuery.FieldDefs);

to store field definitions for the existing table for later use - eg.
to validate text file line according to data types in the table -
without keeping whole Query object.

However, in FPC 2.2.2, I get Access Violation - in
TDefCollection.SetItemName(). If I pass in TDataSet to
TFieldDefs.Create() call, everything is OK.

Is there a way to use TFieldDefs without TDataSet? Or should I use the
list of TFieldDef objects instead? Any other suggestion to keep the
list of fields in the table for later use?

Thanks,

  Erik

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tatamata · 2009-01-01 16:53

Why don't you try with MemDataset? Since it is in memory, it seems to
be a good way for temporary storage of FieldDefs inormation.
Put MemDtaset control on yor form and then you can create FieldDefs
through code in this way:

var
  vFieldDef:TFieldDef;
begin
  vFieldDef:=MemDataset1.FieldDefs.AddFieldDef;
  //and then add properties of the FieldDef...
  vFieldDef.Name:='SomeName';

  vFieldDef.DataType:=ftString;

  vFieldDef.Size:=1000;

  vFieldDef.Required:=False;

Etc.

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Loesje · 2009-01-19 10:01

It was a bug in fpc, it's fixed in revision 12567