IDE Window: Variable Inspector

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You must setup the debugger and start the project to debug it. Only then will this window be useful.

Variable Inspector

Also known as "Debug Inspector"

Debug Inspector.png

This window allows you to watch an expression. If the expression is a structure, then each field is displayed as a separate entry.

Expressions can be local or global variables, (certain) properties, or Pascal expressions (limited support, e.g. "a+1"). See here for more information


  • The Variable Inspector does not automatically follow the changes of current Thread or Stack. You can toggle the "use instance class" setting, to refresh the result.
  • This dialog is not affected by the History dialog.
  • If the result is a structure that has properties, they may not be included.

Scope (Stackframe, Thread)

The values are evaluated according to the scope set in the Thread and Stack dialog at the time you set the expression. The default scope is the current Thread and top stack frame. Both dialogs (Stack and Frame) offer to change the "current" Frame/Thread.


Setting the value
The interface does not currently provide any method to change the expression from within the dialog. (This was added to Lazarus past version 1.0).
The value can be set from the Watch list (via context menu of an existing watch) or the Evaluate Window.

If the data is a structure with methods, they are displayed separately.

Context menu

Debug Inspector context.png

Use Instance class type
Objects are normally shown according to the declaration of the watched expression. Showing "Sender: TObject" will only show you data, that is declared in TObject. However object variables can contain objects of inherited classes. Sender may be a TForm. Using this the debugger will find the actual class of the object and display all data.

See Also