How to share Sub Report Data with the Main Report

Credit: SebastianT

A report contains a sub report. Data from the sub report is required for calculations in the main report. How can you share sub report data with the main report in version 7 (or higher) of the Crystal Reports Designer?

Shared variables make it easier to pass values from a subreport to the main report. Using shared variables requires two formulae: one to store the value in a shared variable, the other to retrieve the value from the shared variable.

The most important thing to remember when using shared variables is that Crystal Reports must first evaluate the formula where the value is stored before evaluating the formula that retrieves the shared variable.

 

For example if you want to pass a grand total from the subreport to do a calculation in the main report, follow these steps:

1. In the subreport, create a formula similar to the one below:

//@SubFormula
//Stores the grand total of the
//{Orders.Order Amount} field
//in a currency variable called 'myTotal'
WhilePrintingRecords;
Shared CurrencyVar myTotal := Sum ({Orders.Order Amount})

 

2. Place this formula in your subreport.

3. In the main report, create a formula that declares the same variable name: 
//@MainFormula
//Returns the value that was stored
//in the shared currency variable called
//myTotal in the subreport
WhilePrintingRecords;
Shared CurrencyVar myTotal;
myTotal

4. Place @MainFormula in a main report section that is beneath the section containing the subreport.

NOTE:
For the shared variable to return the correct value in the main report, you must place @MainFormula in a main report section that is beneath the section containing the subreport. This ensures Crystal Reports evaluates the @SubFormula before @MainFormula.

One way to do this is to insert a section below the section containing the subreport, and place @MainFormula in this new sub-section:

· On the ‘Format’ menu, click ‘Section’.

· On the ‘Sections’ list, click the section containing the subreport.

· Click ‘Insert’ (at top of dialog box). This inserts an additional subsection.

· Click ‘OK’ to return to the report, and insert @MainFormula into this new sub-section.

The next time you preview the report, @MainFormula displays the value from the subreport. In this particular example, that value was the grand total of the {Orders.Order Amount} field.

5. Once you have verified that @MainFormula is returning the correct value from the subreport, you can include this formula in other main report formulas, such as:

//@NewFormula
//includes data from subreport
{@MainFormula} + Sum ({Customer.Last Year's Sales})

· Place this formula in the same section as @MainFormula, or in a section further down on the report.

You have now successfully shared data from a subreport with the main report.

NOTE:
This is not possible with On Demand Subreports in Crystal Reports since the report will not be processed until after clicking report.

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