how can i evaluate a TStringGrid in debug ?

[Nono Reading Activity]

Greetings,
i can't understand how to use the debug/evaluate with some objet.
In debug, if i want to check tstringgrid.rowcount or tstringgrid.cells[a,b] in a TStringGrid, it show me "member not found"
what am i doing wrong ?
thanks in advance.

[Handoko]

Sorry for not answering your question.

I don't use that debug tool often. Instead I usually use:

Code: Pascal  [Select][+][-]

1.   Form1.Caption := StringGrid1.Cells[a, b];

[rvk]

The debugger is not as perfect as the one in Delphi.
It can't evaluate property getters yet.
And TStringGrid.RowCount is a property with a getter function.

Code: Pascal  [Select][+][-]

1.     property RowCount: Integer read GetRowCount write SetRowCount default 5;

You can get the value by accessing the correct field directly (normally the Fxxx variant).
For TStringGrid you can put this in a watch (or Ctrl+F7): StringGrid1.FRows.Count.

FRows is the direct variable for the rows and Count is a value of FRows.
And Count for FRows is not a getter but a direct read for Count in the TList FRows.
(otherwise you would have needed to do StringGrid1.FRows.FCount which also works)

[Martin_fr]

Lazarus 3.0

For a single cell, enter as watch:

Code: Text  [Select][+][-]

1. PCellProps((TFpList((StringGrid1.FGrid.FCellArr.FCols.FList)^[1]).FList)^[1])^

Modify either of the "1" to see other chells.

In fact, you can watch

Code: Text  [Select][+][-]

1. StringGrid1.GetCells(1,1)

if you enable function calls (Tools > Options > Debugger) and then again in the watch properties.
https://wiki.freepascal.org/FpDebug-Watches-FunctionEval

Mind that only works, because StringGrid1.GetCells is virtual/overridden.

Since it involves strings, it needs DWARF-3 (project settings).


For non virtual methods there is a bug in FPC.

[rvk]

Lazarus 3.0

For a single cell, enter as watch:

Code: Text  [Select][+][-]

1. PCellProps((TFpList((StringGrid1.FGrid.FCellArr.FCols.FList)^[1]).FList)^[1])^

Modify either of the "1" to see other chells.

Hahaha, to make it easy 

Hopefully FpDebug will get the option to view properties (with or without getters) in the future, like Delphi 

[Martin_fr]

Hopefully FpDebug will get the option to view properties (with or without getters) in the future, like Delphi 

That depends on if the FPC team is going to add this to the debug info.

[rvk]

Hopefully FpDebug will get the option to view properties (with or without getters) in the future, like Delphi 

That depends on if the FPC team is going to add this to the debug info.

Might not be "if" but "when" 
I thought work on that has started.
(At least that's what you typed two years ago  )

https://wiki.freepascal.org/FpDebug#Properties

FPC needs a way to actually add info about the "properties" to the debug info. (as of end 2021: work has begun...)

But FpDebug already has come a long way.

I did find that my trunk install still defaulted to gdb.
I wonder if, with gdb now crashing in Lazarus with DWARF 3, and DWARF 3 being the default for AMD64, FpDebug should be default?

(but maybe that's offtopic for this thread)

[Martin_fr]

Hopefully FpDebug will get the option to view properties (with or without getters) in the future, like Delphi 

That depends on if the FPC team is going to add this to the debug info.

Might not be "if" but "when" 
I thought work on that has started.
(At least that's what you typed two years ago  )

https://wiki.freepascal.org/FpDebug#Properties

FPC needs a way to actually add info about the "properties" to the debug info. (as of end 2021: work has begun...)

Well, yes... And nothing since.

I did find that my trunk install still defaulted to gdb.

It should have asked at startup. But asked only once (as part of the --setup dialog).

Other than that once off question, a new install honours old config. If there is no old config, then it should setup fpdebug as default.

[rvk]

I did find that my trunk install still defaulted to gdb.

It should have asked at startup. But asked only once (as part of the --setup dialog).

Other than that once off question, a new install honours old config. If there is no old config, then it should setup fpdebug as default.

Ha, yes. I see now. I probably had a setting from earlier today with the 2.2.4 install.

The StringGrid1.GetCells(1,1) works perfect too 

[Martin_fr]

Lazarus 3.0

For a single cell, enter as watch:

Code: Text  [Select][+][-]

1. PCellProps((TFpList((StringGrid1.FGrid.FCellArr.FCols.FList)^[1]).FList)^[1])^

Modify either of the "1" to see other chells.

Hahaha, to make it easy 

I actually wanted to go a step further than the above, but it turned out 3.0RC1 has a bug...

Now, the bug is fixed in the branch, and 3.0RC2 will be able to do the below:
(mind the .. ranges)

Code: Text  [Select][+][-]

1. PCellProps((TFpList((StringGrid1.FGrid.FCellArr.FCols.FList)^[0..6]).FList)^[0..5])^.Text

This returns an: Array[column] of Array[row] of pchar.
- 6 columns
- 5 rows in each column

The watches window, allows to browse them, as shown in the image.

Empty cells, return an error (for their array entry), because the grid has a nil value in the pointer to their date (and nil dereference is an error).

Data used:

Code: Pascal  [Select][+][-]

1. StringGrid1.Cells[1,1]:='Column:1 Row: 1';
2. StringGrid1.Cells[1,2]:='Column:1 Row: 2';
3. StringGrid1.Cells[2,1]:='Column:2 Row: 1';

Of course you can replace the "5" in "0..5" with "StringGrid1.FRows.FCount". And do similar for the column count.
But mind, that this means a grid with 1000 rows will have the debugger evaluate them all.

[Martin_fr]

The ".." intrinsic: https://wiki.freepascal.org/FpDebug-Watches-Intrinsic-Functions#Array_slice_MyArray.5Bn..m.5D_with_mapping

The new watches window: https://wiki.freepascal.org/IDE_Window:_Watch_list