Problem with the const

[ChrisW67]

What I am doing is for a qtableview I am getting a value from 3rd row, and I send to a function in another class to calculate it. I need to send a string to calculate the value of it. In return I need this double to be on column 5th.

if (index.column() == 5){
                      calculate(index.sibling(index.row(),3).data().toString());
		}

if (index.column() == 5){
                      calculate(index.sibling(index.row(),3).data().toString());
		}

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You are discarding the return value from the function: the result won't appear anywhere.

[aekilic]

this is why I forget to write

normaly code is like this

if (index.column() == 5){
			double d = form.calculate(index.sibling(index.row(),3).data().toString());
			return QString("%L1").arg((d),0,'f',2).leftJustified(true);
		}

if (index.column() == 5){
			double d = form.calculate(index.sibling(index.row(),3).data().toString());
			return QString("%L1").arg((d),0,'f',2).leftJustified(true);
		}

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[faldzip]

So can you paste your exact code? Because none of your snippets makes any sense. Maybe the last one is a bit more clear but still we can't deduce how form was declared and what the hell it is? :P In previous snippets you had calculate in different classes and calling it as it would be in one class... And what is:

id_st=id;

id_st=id;

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??
And can you paste the exact error you get?

[aekilic]

form.h

class form:public QDialog, Ui::form
{
	Q_OBJECT
	public:
	bool isUpdate;
       QString totaID;
 	form(QWidget *parent = 0
 			, const QString &uid = QString::nulll);
	public slots:
	double calculate(const QString &id);
};
 
#endif

class form:public QDialog, Ui::form
{
	Q_OBJECT
	public:
	bool isUpdate;
       QString totaID;
 	form(QWidget *parent = 0
 			, const QString &uid = QString::nulll);
	public slots:
	double calculate(const QString &id);
};

#endif

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form.cpp

double form::calculate(const QString &id)
{
	totaID = id;
	load();
 
	return spin->value();
}

double form::calculate(const QString &id)
{
	totaID = id;
	load();

	return spin->value();
}

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and after that I create a custom sqltablemodel

QVariant CustomSql::data(const QModelIndex &index, int role) const
      {
      QVariant value = QSqlTableModel::data(index, role);
      if (value.isValid() && role == Qt::DisplayRole) {
      if (index.column() == 5){
           calculate(index.sibling(index.row(),3).data().toString());
           return QString("%L1").arg((d),0,'f',2).leftJustified(true);
           }
           return value.toString().leftJustified(true);
      }
      return value;
 }

QVariant CustomSql::data(const QModelIndex &index, int role) const
      {
      QVariant value = QSqlTableModel::data(index, role);
      if (value.isValid() && role == Qt::DisplayRole) {
      if (index.column() == 5){
           calculate(index.sibling(index.row(),3).data().toString());
           return QString("%L1").arg((d),0,'f',2).leftJustified(true);
           }
           return value.toString().leftJustified(true);
      }
      return value;
 }

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am I clear?

[faldzip]

No, your code doesn't make any sense. You didn't show us your CustomSql::calculate() method, and d is undefined. Also load() method is not defined. And we still don't know what is the exact error you get?

[wysota]

I have a quick question for you...

Why would you want to recalculate the value over and over again when something calls data()?

In other words - why not calculate it once when it changes and then just return the earlier calculated value from data()?