How do I insert a slide into another PowerPoint slide using OpenXML?

Question

I would like to take a PowerPoint slide (the "source"), and insert it into another PowerPoint slide (the "target") that already contains some content, at a specific position in the source PowerPoint slide.

I've tried several ways to research code that does this, but I keep getting results for merging slides into PowerPoint presentations, which is not what I want. I want to take an existing slide and insert it into another, much like one would insert a picture into an existing slide.

I have code that another coworker wrote that clones all of the elements from the source slide, but it is convoluted and uses different code variations for different element types. Here is a representative sample of that code:

foreach (OpenXmlElement element in sourceSlide.CommonSlideData.ShapeTree.ChildElements.ToList())
{
    string elementTypeName = element.GetType().ToString();

    if (elementTypeName.EndsWith(".Picture"))
    {
        // Deep clone the element.
        elementClone = element.CloneNode(true);

        // Adjust the offsets so it is positioned correctly.
        ((Picture)elementClone).ShapeProperties.Transform2D.Offset.X += (Int64)shapeStruct.OffsetX;
        ((Picture)elementClone).ShapeProperties.Transform2D.Offset.Y += (Int64)shapeStruct.OffsetY;

        // Get the shape tree that we're adding the clone to and append to it.
        ShapeTree shapeTree = slideCard.CommonSlideData.ShapeTree;
        shapeTree.Append(elementClone);

        string rId = ((Picture)element).BlipFill.Blip.Embed.Value;

        ImagePart imagePart = (ImagePart)slideInstProc.SlidePart.GetPartById(rId);
        string contentType = imagePart.ContentType;

        // Locate the same object we cloned over to the slide.
        var blip = ((Picture)elementClone).BlipFill.Blip;

        slidePart = slideCard.SlidePart;

        try
        {
            ImagePart imagePart1 = slidePart.AddImagePart(contentType, rId);
            imagePart1.FeedData(imagePart.GetStream());
        }
        catch (XmlException)
        {
            //Console.WriteLine(xe.ToString());
            Console.WriteLine("Duplicate rId (" + rId + ")");
        }
    }
    if (elementTypeName.EndsWith(".GroupShape"))
    {
        ... etc

The code continues with an else-if ladder containing blocks of code for element type names ending with .GroupShape , .GraphicFrame , .Shape , and .ConnectionShape , concluding with a catchall else at the bottom.

The problem is this code doesn't process some types of objects properly. For one thing, it doesn't process drawings at all (perhaps because some of them originated from an older version of PowerPoint), and when it does, it does things like change the color of the drawing.

What I was hoping is that there was a more fundamental way (ie simpler, generic code) to embed a source PowerPoint slide into another, treating it like a single object, without looking at element types within the source PowerPoint specifically.

Alternatively, what would be the way to process drawings or images in ordinary "shapes" that don't identify themselves specifically as images?

Answer 1

This is the code that solved the specific problem I was describing above:

using A = DocumentFormat.OpenXml.Drawing;

foreach(A.BlipFill blipFill in shape.Descendants<A.BlipFill>())
{
    string rId = blipFill.Blip.Embed.Value;
    ImagePart imagePart = (ImagePart)slideInstProc.SlidePart.GetPartById(rId);
    string contentType = imagePart.ContentType;

    try
    {
        ImagePart imagePart1 = slidePart.AddImagePart(contentType, rId);
        imagePart1.FeedData(imagePart.GetStream());
    }
    catch (XmlException)
    {
        Console.WriteLine("Duplicate rId (" + rId + ")");
    }
}

Which, when applied to elementTypeName.EndsWith(".shape"); produces exactly the result I want.

For composing complete slides into a presentation (which doesn't require some of the generation mechanics that we do), OpenXmlPowerTools is a much better approach.