In Delphi this will work even if the Sender is not a TdbGrid, as long as it has a DataSource property:

? TdbGrid(Sender).datasource:=myDataSource;

But it won't work in Lazarus if Sender is a different dbAware component., the compiler will complain it's not a dbGrid.

Is there anyway to accomplish this same result in Lazarus, perhaps by using RTTI?? Or is there a compiler directive to stop this check?

An example would be great.? Thanks.

A. G.
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In Delphi this will work even if the Sender is not a TdbGrid, as long as it has a DataSource property:

It only *happens* to work for you in Delphi.

TdbGrid(Sender).datasource:=myDataSource;

This hack requires that Sender has a DataSource property in *exactly* the same place where it sits in TdbGrid. That's very unlikely for any other class.

DoDi

Depending on what the Sender is it might work if it can be cast to a TDBGrid. Can you actually run an application with that cast? What is the Sender?

I put a DBGrid and a DBMemo on a form and in the OnShow assigned the DataSource property of each to a DataSource I had also placed on the form. Everything worked as expected. Then I changed the assignment to the DBMemo to the following:

TDBGrid(DBMemo1).DataSource := DataSource1;

Both a syntax check and a build did not throw any errors but if I attempted to run the application it would error out with an access violation as soon as it got to the above assignment.

I think that FPC is just catching it at compile time while Delphi is not.

Bob

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Note that there is also a runtime check available for this in FPC. It is called -CR and very, very useful.

And in trunk it even raises an explicit exception class instead of merely an exception: EObjectCheck. :)

Regards,
Sven

OK, how about a compiler switch (that can be turned on or off) that SEARCHES for the property (or event if defined in code and not by the Object Inspector)?? It shouldn't be so difficult to deal with Sender (or components in a loop) where the exact Type is not known in advance, just the presence of a specific property or Event.? If the switch can be turned Off again after the routine, the impact on performance shouldn't be a concern.? Greater flexibility and ease of use, especially for newbies (RTTI is difficult and poorly documented) is needed if freepascal/Lazarus is to become universally adopted.

Can there please be a discussion on this?? Thanks!

A. G.

On Thursday, January 30, 2014 3:58 PM, Alejandro Gonzalo wrote:

OK, how about a compiler switch (that can be turned on or off) that SEARCHES for the property (or event if defined in code and not by the Object Inspector)?? It shouldn't be so difficult to deal with Sender (or components in a loop) where the exact Type is not known in advance, just the presence of a specific property or Event.? If the switch can be turned Off again after the routine, the impact on performance shouldn't be a concern.? Greater flexibility and ease of use, especially for newbies (RTTI is difficult and poorly documented) is needed if freepascal/Lazarus is to become universally adopted.?

Can there please be a discussion on this?? Thanks!

A. G.

On Friday, January 17, 2014 6:22 PM, Hans-Peter Diettrich wrote:

In Delphi this will work even if the Sender is not a TdbGrid, as long as it has a DataSource property:

It only *happens* to work for you in Delphi.

? TdbGrid(Sender).datasource:=myDataSource;

This hack requires that Sender has a DataSource property in *exactly* the same place where it sits in
TdbGrid. That's very unlikely for any
other class.

DoDi
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You just need to understand what you are doing, and use

   SetObjectProp(Sender,'Datasource',MyDataSource);

that's all there is to it.

Michael.

Is there also a way of setting an event such as OnEnter for Sender or a Component in a loop (if the Event is defined in code and not with the Object Inspector)?

Thank you.

A. G.

On Friday, January 31, 2014 12:19 AM, Michael Van Canneyt wrote:

You just need to understand what you are doing, and use

?  SetObjectProp(Sender,'Datasource',MyDataSource);

that's all there is to it.

Michael.

Alejandro Gonzalo wrote

Is there also a way of setting an event such as OnEnter for Sender or a Component in a loop (if the Event is defined in code and not with the Object Inspector)?

Yes, take a look here:
http://freepascal.org/docs-html/rtl/typinfo/setmethodprop.html

Regards,
Sven