Updating Table Values.

[jacek]

There are three solutions:

1) pass a pointer to the first dialog

SecondDialog::SecondDialog( FirstDialog *ptr, QWidget *parent  )
   : QDialog( parent ), _firstDialogPtr( ptr )
{
   ... 
}
 
...
 
void SecondDialog::processParams()
{
   ...
   _firstDialogPtr->setSomenting( whatever );
   ...
}

SecondDialog::SecondDialog( FirstDialog *ptr, QWidget *parent  )
   : QDialog( parent ), _firstDialogPtr( ptr )
{
   ... 
}

...

void SecondDialog::processParams()
{
   ...
   _firstDialogPtr->setSomenting( whatever );
   ...
}

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This is quite easy solution, but it also the worst one (except for the one with global variables which I won't even mention). It's bad, because both dialogs are tightly coupled.

2) use accessor methods to retrieve data from the SecondDialog:

void FirstDialog::doSomething()
{
   SecondDialog dlg( this );
   if( dlg.exec() == Qt::Accepted ) {
      someWidget->setSomething( dlg.something() ); // SecondDialog::something() returns the data you need
      ...
   }
}

void FirstDialog::doSomething()
{
   SecondDialog dlg( this );
   if( dlg.exec() == Qt::Accepted ) {
      someWidget->setSomething( dlg.something() ); // SecondDialog::something() returns the data you need
      ...
   }
}

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This is a bit better approach, since you can reuse SecondDialog for other purposes.

3) Use signals and slots:

void FirstDialog::showSecondDialog()
{
   SecondDialog *dlg = new SecondDialog( this );
   dlg->setWFlags( dlg->getWFlags() | Qt::WDestructiveClose );
 
   connect( dlg, SIGNAL( somethingChanged( int ) ), 
            this, SLOT( setSomething( int ) ) );
   ...
 
   dlg->show();
}

void FirstDialog::showSecondDialog()
{
   SecondDialog *dlg = new SecondDialog( this );
   dlg->setWFlags( dlg->getWFlags() | Qt::WDestructiveClose );

   connect( dlg, SIGNAL( somethingChanged( int ) ), 
            this, SLOT( setSomething( int ) ) );
   ...

   dlg->show();
}

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This is the version with minimal coupling, but it also requires a bit more work than other ones.

[kenny_isles]

Hi

The code is working however i want to know why the following approach dosnt work.
I will attach the code segment also.

Parameter_Selection_Dlg *b = new Parameter_Selection_Dlg(this);
b->show();
b->ChoosenParam_lb->setCurrentItem(0);
table1->setText(1,1,b->ChoosenParam_lb->currentText());

A is a dialog box which has a table and B is another class that has a list box.
As the above I am trying to upload the values into from B to A.
So ChoosenParam_lb is the List box name residing in Class B.
table1 is the name of the table.

Plz tell me as to why it is not showing the values.

With Regards
Kenny.

[kenny_isles]

This is the second method u suggested