Exporting a grid with joined columns in csv format / Excel doubles Custom Header

[RalfNiehausIVE]

Describe the bug

When exporting a grid with joined columns the result csv output shows only the joined value.

If I define a custom header to merge the two headers, the excel export doubles the custom header.

It is not possible to define only a custom header for the csv export. So I have to decide which output is broken csv or excel.

Expected behavior

No response

Minimal reproducible example

CSV shows only joined Header

@Route("grid-exporter-test")
@PermitAll
public class GridExporterTest extends VerticalLayout {

    record Person(String firstname, String lastname) {}

    public GridExporterTest() {
        Grid<Person> grid = new Grid<>();
        var colFirstname = grid.addColumn(Person::firstname).setHeader("Firstname");
        var colLastname = grid.addColumn(Person::lastname).setHeader("Lastname");
        grid.setItems(new Person("Alice", "Bob"), new Person("Jane", "Doe"));

        HeaderRow headerRow = grid.prependHeaderRow();
        Div cellTotal = new Div("Joined cells");
        cellTotal.getStyle().set("text-align", "center");
        headerRow.join(colFirstname, colLastname).setComponent(cellTotal);

        GridExporter gridExporter = GridExporter.createFor(grid);
        gridExporter.setAutoAttachExportButtons(true);
        gridExporter.setTitle("MontageFortschritt");

        add(grid);
    }
}

Excel doubles Custom Header

@Route("grid-exporter-test")
@PermitAll
public class GridExporterTest extends VerticalLayout
{

    record Person(String firstname, String lastname) {}

    public GridExporterTest()
    {
        Grid<Person> grid = new Grid<>();
        var colFirstname = grid.addColumn(Person::firstname).setHeader("Firstname");
        var colLastname = grid.addColumn(Person::lastname).setHeader("Lastname");
        grid.setItems(new Person("Alice", "Bob"), new Person("Jane", "Doe"));

        HeaderRow headerRow = grid.prependHeaderRow();
        Div cellTotal = new Div("Joined cells");
        cellTotal.getStyle().set("text-align", "center");
        headerRow.join(colFirstname, colLastname).setComponent(cellTotal);

        GridExporter gridExporter = GridExporter.createFor(grid);
        gridExporter.setAutoAttachExportButtons(true);
        gridExporter.setTitle("MontageFortschritt");

        gridExporter.setCustomHeader(colFirstname, "join_firstName");
        gridExporter.setCustomHeader(colLastname, "join_lastName");

        add(grid);
    }

Add-on Version

2.5.2

Vaadin Version

24.5.14

Additional information

No response

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🔗 Similar Issues

Possible Duplicates

• Exporting a grid with joined columns in excel format #176

Related Issues

• java.lang.ArrayStoreException #170
• Exporting fails when there are no footers attached #163
• extractValueFromColumn should respect custom ValueProvider return value, even if null #182
• IndexOutOfBoundsException when using createFor(grid) before grid added to UI GridHelpers#129

🔗 Related PRs

#133 - Fix problem when exporting grids with only one column [merged]
#154 - feat: add support for multiple header rows [merged]
#178 - fix: preserve joined headers [merged]

👤 Suggested Assignees

• brunoagretti
• mlopezFC
• paulobaratarobbialac
• NicoDevX
• a-schild

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[scardanzan]

We defined a few issues from this:

1. Csv export is using the first header row as the header, we belive it should use the last since joined rows are not a feature of csv. Given that we will update the exporter to use the header closer to the data, using the custom header values if present.
2. Excel export is using the custom header text for all the column headers. We will fix it so the custom headers are only used for the header row closer to the data.
3. There is no way to add custom headers to extra header rows. This will not be fixed at this point since we consider that to be an enhancement, the progress for that can be tracked in this isssue Support adding custom headers to any header cell. #201