Come applicare la formattazione personalizzata durante Mail Merge

La classe MailMerge fornisce due eventi che potrebbero essere molto utili per espandere le capacità di Mail Merge. La proprietà setFieldMergingCallback(IFieldMergingCallback) accetta una classe che implementa i metodi fieldMerging(FieldMergingArgs) e imageFieldMerging(ImageFieldMergingArgs). Questi possono essere utilizzati per implementare il controllo personalizzato sul processo Mail Merge.

L’evento fieldMerging(FieldMergingArgs) si verifica durante Mail Merge quando viene rilevato un campo semplice Mail Merge nel documento. Questo dà ulteriore controllo su Mail Merge ed è possibile eseguire qualsiasi azione quando si verifica l’evento. Questo metodo è racchiuso in una classe che implementa l’interfaccia IFieldMergingCallBack e accetta un oggetto FieldMergingArgs che fornisce dati per l’evento corrispondente.

L’esempio di codice riportato di seguito illustra come implementare la logica personalizzata nell’evento MergeField per applicare la formattazione delle celle.

// 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;
}