Modify/Change Report Parameters at Runtime for Print/Export

Knowledgebase English KB
1
Valid from List & Label 19
Report parameters are a very good way to let the user pre-filter the data interactively or to change it later in the preview. However, in order to be able to make a certain preselection of the available report parameters in your own code, the so-called DOM (Document Object Model) from List & Label can be used. The DOM-API is available from the Professional Edition. The following section uses simple code examples to illustrate how to do this.

DOM with C++:
After starting the print/export, DOM is used to load the currently used project and access its report parameters. 
...
::LlPrintWithBoxStart(m_hJob, LL_PROJECT_LIST, sFileName,
                      LL_PRINT_EXPORT,
                      LL_BOXTYPE_STDABORT, hWnd, _T("Printing...")
                      );

HLLDOMOBJ hProj = NULL;
::LlDomGetProject(m_hJob, &hProj);

HLLDOMOBJ hReportParameterList = NULL;	
::LlDomGetObject(hProj, _T("ReportParameters"), &hReportParameterList);

HLLDOMOBJ hReportParameter = NULL;
::LlDomGetSubobject(hReportParameterList, 0, &hReportParameter);
::LlDomSetProperty(hReportParameter, _T("CurrentContents"), _T("Content"));
...


DOM with C#:
When using the. NET component, the contents of the report parameters can be controlled via an event by accessing the current project in the event.

...
LL.ReportParametersCollected += OnReportParametersCollected;
LL.Export(new ExportConfiguration(LlExportTarget.Pdf, @"C:\temp\Report.pdf", "Test.lst"));
...
private void OnReportParametersCollected(object sender, ReportParametersCollectedEventArgs e)
{
    // This is not required to set a simple value for a parameter,
    // for report parameters with a fixed set of available options (a list of checkboxes in the preview)
    // but the possible options can be determined via the event arguments:
    // e.ReportParameters[...].Choices
    // In case of errors, this event is triggered again and the error message can be retrieved via:
    // e.NeedDataErrorClient
    
    // Here, the currently loaded project is accessed via DOM
    using (var project = new ProjectList(sender as ListLabel))
    {
        project.GetFromParent();

        // The report parameters can be determined here
        foreach (ReportParameter param in project.ReportParameters)
        {
            // And set the value for a particular parameter
            if (param.Identifier == "@MyReportParameter")
            {
                param.CurrentContents = "Content";
            }
        }
    }
	
    // With "Continue" the export is continued, with "Abort" you can cancel it here
    // also if e. g. not all necessary values were available
    e.ReturnType = ReportParametersCollectedReturnType.Continue;
}
...
IDKBTE001350 KBTE001350