Jak použít vlastní formátování během Mail Merge

Třída MailMerge poskytuje dvě události, které by mohly být velmi užitečné při rozšiřování funkcí Mail Merge. Vlastnost setFieldMergingCallback(IFieldMergingCallback) přijímá třídu, která implementuje metody fieldMerging(FieldMergingArgs) a imageFieldMerging(ImageFieldMergingArgs). Ty lze použít k implementaci vlastní kontroly nad procesem Mail Merge.

Událost fieldMerging(FieldMergingArgs) nastane během Mail Merge, když se v dokumentu objeví jednoduché pole Mail Merge. To dává další kontrolu nad Mail Merge a můžete provádět jakékoli akce, když dojde k události. Tato metoda je zabalena do třídy, která implementuje rozhraní IFieldMergingCallBack a přijímá objekt FieldMergingArgs, který poskytuje data pro odpovídající událost.

Příklad kódu uvedený níže ukazuje, jak implementovat vlastní logiku v události MergeField pro použití formátování buňky.

// For complete examples and data files, please go to https://github.com/aspose-words/Aspose.Words-for-Java
public class ApplyCustomFormattingDuringMailMerge {

    private static final String dataDir = Utils.getSharedDataDir(ApplyCustomFormattingDuringMailMerge.class) + "MailMerge/";

    public static void main(String[] args) throws Exception {
        Document doc = new Document(dataDir + "MailMerge.AlternatingRows.doc");

        // Add a handler for the MergeField event.
        doc.getMailMerge().setFieldMergingCallback(new HandleMergeFieldAlternatingRows());

        // Execute mail merge with regions.
        DataTable dataTable = getSuppliersDataTable();
        doc.getMailMerge().executeWithRegions(dataTable);

        doc.save(dataDir + "MailMerge.AlternatingRows Out.doc");
    }

    /**
     * Returns true if the value is odd; false if the value is even.
     */
    public static boolean isOdd(int value) throws Exception {
        return (value % 2 != 0);
    }

    /**
     * Create DataTable and fill it with data. In real life this DataTable
     * should be filled from a database.
     */
    private static DataTable getSuppliersDataTable() throws Exception {
        java.sql.ResultSet resultSet = createCachedRowSet(new String[]{"CompanyName", "ContactName"});

        for (int i = 0; i < 10; i++)
            addRow(resultSet, new String[]{"Company " + Integer.toString(i), "Contact " + Integer.toString(i)});

        return new DataTable(resultSet, "Suppliers");
    }

    /**
     * A helper method that creates an empty Java disconnected ResultSet with
     * the specified columns.
     */
    private static ResultSet createCachedRowSet(String[] columnNames) throws Exception {
        RowSetMetaDataImpl metaData = new RowSetMetaDataImpl();
        metaData.setColumnCount(columnNames.length);
        for (int i = 0; i < columnNames.length; i++) {
            metaData.setColumnName(i + 1, columnNames[i]);
            metaData.setColumnType(i + 1, java.sql.Types.VARCHAR);
        }

        CachedRowSet rowSet = RowSetProvider.newFactory().createCachedRowSet();
        ;
        rowSet.setMetaData(metaData);

        return rowSet;
    }

    /**
     * A helper method that adds a new row with the specified values to a
     * disconnected ResultSet.
     */
    private static void addRow(ResultSet resultSet, String[] values) throws Exception {
        resultSet.moveToInsertRow();

        for (int i = 0; i < values.length; i++)
            resultSet.updateString(i + 1, values[i]);

        resultSet.insertRow();

        // This "dance" is needed to add rows to the end of the result set properly.
        // If I do something else then rows are either added at the front or the result
        // set throws an exception about a deleted row during mail merge.
        resultSet.moveToCurrentRow();
        resultSet.last();
    }
}

class HandleMergeFieldAlternatingRows implements IFieldMergingCallback {
    /**
     * Called for every merge field encountered in the document. We can either
     * return some data to the mail merge engine or do something else with the
     * document. In this case we modify cell formatting.
     */
    public void fieldMerging(FieldMergingArgs e) throws Exception {
        if (mBuilder == null)
            mBuilder = new DocumentBuilder(e.getDocument());

        // This way we catch the beginning of a new row.
        if (e.getFieldName().equals("CompanyName")) {
            // Select the color depending on whether the row number is even or odd.
            Color rowColor;
            if (ApplyCustomFormattingDuringMailMerge.isOdd(mRowIdx))
                rowColor = new Color(213, 227, 235);
            else
                rowColor = new Color(242, 242, 242);

            // There is no way to set cell properties for the whole row at the moment,
            // so we have to iterate over all cells in the row.
            for (int colIdx = 0; colIdx < 4; colIdx++) {
                mBuilder.moveToCell(0, mRowIdx, colIdx, 0);
                mBuilder.getCellFormat().getShading().setBackgroundPatternColor(rowColor);
            }

            mRowIdx++;
        }
    }

    public void imageFieldMerging(ImageFieldMergingArgs args) throws Exception {
        // Do nothing.
    }

    private DocumentBuilder mBuilder;
    private int mRowIdx;
}