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Data access components in a DLL

    I need to create dlls with data access components embedded within
them. They build without errors, but I get an exception when calling
them. Any ideas/components out there?

respond to adr...@vhb.com

thanks.

 

Re:Data access components in a DLL


On 9 Jun 1996 17:01:28 GMT, a...@ix.netcom.com (Adrian Zelazny ) wrote:

Quote
>    I need to create dlls with data access components embedded within
>them. They build without errors, but I get an exception when calling
>them. Any ideas/components out there?

>respond to adr...@vhb.com

>thanks.

Someone might have an idea if you could tell us what the exception is.
{*word*106} MacDonald

Re:Data access components in a DLL


Richard ,

I presume you are creating your objects on-the-fly rather than using a
form.

In general, it's a matter of creating the components correctly, if not
created properly, you generally get memory access violations because
uninitialized pointers are used.

I know this sound glib, but your question certainly lacks detail.

For example, to create TTables and DataSources (this is a snippet from
working DLL code):

var
  Customer:TTable;
  Price:TTable;
  PriceDS:TDataSource;
  Price2DS:TDataSource;
  ProductDS:TDataSource;
  Product2DS:TDataSource;

procedure OpenTables;
begin
try
PriceDS:=TDataSource.Create(nil);
Price2DS:=TDataSource.Create(nil);
ProductDS:=TDataSource.Create(nil);
Product2DS:=TDataSource.Create(nil);

Customer := TTable.Create(Nil);
Customer.DatabaseName:=TableDir;
Customer.TableName:=TableName1;
Customer.active:=true;

Price := TTable.Create(Nil);
Price.DatabaseName:=TableDir;
Price.TableName:=TableName2;
Price.IndexFieldNames:='Code';
Price.active:=true;
PriceDS.DataSet:=Price;
...

When the DLL closes, you need to destroy the components you create to
recover memory.

--
Paul,           (Mon, 10 June 96, 22:10 EST)
SoftStuff, Croydon, Victoria, Australia, 3136
pa...@linuxserver.pccity.com.au

Quote
On Monday, 10 June 1996, Richard MacDonald wrote...
> On 9 Jun 1996 17:01:28 GMT, a...@ix.netcom.com (Adrian Zelazny ) wrote:

> >    I need to create dlls with data access components embedded within
> >them. They build without errors, but I get an exception when calling
> >them. Any ideas/components out there?

> >respond to adr...@vhb.com

> >thanks.

> Someone might have an idea if you could tell us what the exception is.
>{*word*106} MacDonald

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