ImageFieldMergingArgs

ImageFieldMergingArgs class

Provides data for the ImageFieldMerging event.

public class ImageFieldMergingArgs : FieldMergingArgsBase

Properties

Name Description
Document { get; } Returns the Document object for which the mail merge is performed.
DocumentFieldName { get; } Gets the name of the merge field as specified in the document.
Field { get; } Gets the object that represents the current merge field.
FieldName { get; } Gets the name of the merge field in the data source.
FieldValue { get; set; } Gets or sets the value of the field from the data source.
Image { get; set; } Specifies the image that the mail merge engine must insert into the document.
ImageFileName { get; set; } Sets the file name of the image that the mail merge engine must insert into the document.
ImageHeight { get; set; } Specifies the image height for the image to insert into the document.
ImageStream { get; set; } Specifies the stream for the mail merge engine to read an image from.
ImageWidth { get; set; } Specifies the image width for the image to insert into the document.
RecordIndex { get; } Gets the zero based index of the record that is being merged.
Shape { get; set; } Specifies the shape that the mail merge engine must insert into the document.
TableName { get; } Gets the name of the data table for the current merge operation or empty string if the name is not available.

Remarks

This event occurs during mail merge when an image mail merge field is encountered in the document. You can respond to this event to return a file name, stream, or an Image object to the mail merge engine so it is inserted into the document.

There are three properties available ImageFileName, ImageStream and Image to specify where the image must be taken from. Set only one of these properties.

To insert an image mail merge field into a document in Word, select Insert/Field command, then select MergeField and type Image:MyFieldName.

Examples

Shows how to insert images stored in a database BLOB field into a report.

public void ImageFromBlob()
{
    Document doc = new Document(MyDir + "Mail merge destination - Northwind employees.docx");

    doc.MailMerge.FieldMergingCallback = new HandleMergeImageFieldFromBlob();

    string connString = $"Provider=Microsoft.Jet.OLEDB.4.0;Data Source={DatabaseDir + "Northwind.mdb"};";
    string query = "SELECT FirstName, LastName, Title, Address, City, Region, Country, PhotoBLOB FROM Employees";

    using (OleDbConnection conn = new OleDbConnection(connString))
    {
        conn.Open();

        // Open the data reader, which needs to be in a mode that reads all records at once.
        OleDbCommand cmd = new OleDbCommand(query, conn);
        IDataReader dataReader = cmd.ExecuteReader();

        doc.MailMerge.ExecuteWithRegions(dataReader, "Employees");
    }

    doc.Save(ArtifactsDir + "MailMergeEvent.ImageFromBlob.docx");

private class HandleMergeImageFieldFromBlob : IFieldMergingCallback
{
    void IFieldMergingCallback.FieldMerging(FieldMergingArgs args)
    {
        // Do nothing.
    }

    /// <summary>
    /// This is called when a mail merge encounters a MERGEFIELD in the document with an "Image:" tag in its name.
    /// </summary>
    void IFieldMergingCallback.ImageFieldMerging(ImageFieldMergingArgs e)
    {
        MemoryStream imageStream = new MemoryStream((byte[])e.FieldValue);
        e.ImageStream = imageStream;
    }
}

Shows how to set the dimensions of images as MERGEFIELDS accepts them during a mail merge.

{
    Document doc = new Document();

    // Insert a MERGEFIELD that will accept images from a source during a mail merge. Use the field code to reference
    // a column in the data source containing local system filenames of images we wish to use in the mail merge.
    DocumentBuilder builder = new DocumentBuilder(doc);
    FieldMergeField field = (FieldMergeField)builder.InsertField("MERGEFIELD Image:ImageColumn");

    // The data source should have such a column named "ImageColumn".
    Assert.AreEqual("Image:ImageColumn", field.FieldName);

    // Create a suitable data source.
    DataTable dataTable = new DataTable("Images");
    dataTable.Columns.Add(new DataColumn("ImageColumn"));
    dataTable.Rows.Add(ImageDir + "Logo.jpg");
    dataTable.Rows.Add(ImageDir + "Transparent background logo.png");
    dataTable.Rows.Add(ImageDir + "Enhanced Windows MetaFile.emf");

    // Configure a callback to modify the sizes of images at merge time, then execute the mail merge.
    doc.MailMerge.FieldMergingCallback = new MergedImageResizer(200, 200, MergeFieldImageDimensionUnit.Point);
    doc.MailMerge.Execute(dataTable);

    doc.UpdateFields();
    doc.Save(ArtifactsDir + "Field.MERGEFIELD.ImageDimension.docx");

/// <summary>
/// Sets the size of all mail merged images to one defined width and height.
/// </summary>
private class MergedImageResizer : IFieldMergingCallback
{
    public MergedImageResizer(double imageWidth, double imageHeight, MergeFieldImageDimensionUnit unit)
    {
        mImageWidth = imageWidth;
        mImageHeight = imageHeight;
        mUnit = unit;
    }

    public void FieldMerging(FieldMergingArgs e)
    {
        throw new NotImplementedException();
    }

    public void ImageFieldMerging(ImageFieldMergingArgs args)
    {
        args.ImageFileName = args.FieldValue.ToString();
        args.ImageWidth = new MergeFieldImageDimension(mImageWidth, mUnit);
        args.ImageHeight = new MergeFieldImageDimension(mImageHeight, mUnit);

        Assert.AreEqual(mImageWidth, args.ImageWidth.Value);
        Assert.AreEqual(mUnit, args.ImageWidth.Unit);
        Assert.AreEqual(mImageHeight, args.ImageHeight.Value);
        Assert.AreEqual(mUnit, args.ImageHeight.Unit);
    }

    private readonly double mImageWidth;
    private readonly double mImageHeight;
    private readonly MergeFieldImageDimensionUnit mUnit;
}

See Also