Access Parent Report row from Sub-report

[jakubhertyk]

Hello,

 

I don't think that this is a unique problem to my report but I need to access the current row of the Parent report in the Sub-report.

 

I have a report that generates a Sub-report for every Group Header. This Sub-report uses 12 variables from the current Group Header row of the Parent report. Rather than passing 12 parameters to the Sub-report, I thought that it would be simpler to access the current row of the Parent report where the fields reside. Is there anyway I can accomplish this?

 

Thank you,

 

Jakub :(

Post edited by: jakubhertyk, at: 2007/02/01 22:10

[christiaan_se]

Hi,

you can write a custom datasource which has access to the parent datasource:

Code:

public class ChildDataSource implements JRDataSource {

    private JRDataSource parentDatasource = null;

    public ChildDataSource (ParentDataSource  parentDatasource) {
        super();
        this.parentDatasource = parentDatasource;
    }

    public Object getFieldValue(JRField field) throws JRException {
           Object parentObject = parentDatasource.getCurrentRowObject();
           .... 
    }

}

[jakubhertyk]

Code:

parentDatasource.getCurrentRowObject();

 

The following doesn't appear to be a valid method for JRDataSource. I can't even find one that resembles it.

 

Also, what should I do in the next() method. Iterate the parentDataSource?

 

Thanks,

 

Jakub

[christiaan_se]

Yes sorry about that (and the late reply). It's just example code, not fully functional. The idea is that you provide a custom datasource for both parent and child. As soon next is being called you store that info in an attribute so the child CustomDataSource can easily access this.

 

Code:

public class CustomDataSource implements JRDataSource {

    private CustomDataSource parentDatasource = null;
    private Object currentObject = null;

    public ChildDataSource (ParentDataSource  parentDatasource) {
        super();
        this.parentDatasource = parentDatasource;
    }

    public Object getFieldValue(JRField field) throws JRException {
           if(parentDatasource != null) {
           Object parentObject = parentDatasource.getCurrentRow();
           //now use parentObject to get parent info
           }
           //use currentObject to retrieve info
    }

    public boolean next() throws JRException {
           //process next data
           //assign data to currentObject
    }

    public Object getCurrentObject() {
          return currentObject();
    }
}

 

hope this helps,

Christiaan