TextRange.Save Method (Stream, String)

// This method accepts an input stream and a corresponding data format.  The method 
// will attempt to load the input stream into a TextRange selection, apply Bold formatting 
// to the selection, save the reformatted selection to an alternat stream, and return  
// the reformatted stream.  
Stream BoldFormatStream(Stream inputStream, string dataFormat)
{
    // A text container to read the stream into.
    FlowDocument workDoc = new FlowDocument();
    TextRange selection = new TextRange(workDoc.ContentStart, workDoc.ContentEnd);
    Stream outputStream = new MemoryStream();

    try
    {
        // Check for a valid data format, and then attempt to load the input stream 
        // into the current selection.  Note that CanLoad ONLY checks whether dataFormat 
        // is a currently supported data format for loading a TextRange.  It does not  
        // verify that the stream actually contains the specified format.  An exception  
        // may be raised when there is a mismatch between the specified data format and  
        // the data in the stream.  
        if (selection.CanLoad(dataFormat))
            selection.Load(inputStream, dataFormat);
    }
    catch (Exception e) { return outputStream; /* Load failure; return a null stream. */ }

    // Apply Bold formatting to the selection, if it is not empty. 
    if (!selection.IsEmpty)
        selection.ApplyPropertyValue(TextElement.FontWeightProperty, FontWeights.Bold);

    // Save the formatted selection to a stream, and return the stream. 
    if (selection.CanSave(dataFormat))
        selection.Save(outputStream, dataFormat);

    return outputStream;
}