CSharp: Add Graphical Content inside Excel spreadsheet

In this blog post, I will show you how to add an image (certificate) inside an Excel sheet using OpenXML package in C# DotNet Framework. This is a useful technique when you need to insert some graphical elements into your spreadsheet, such as logos, charts, or certificates.

The basic steps are:

1. Create a spreadsheet document or open an existing one.
2. Add a worksheet part to the document or get an existing one by name.
3. Add a drawings part to the worksheet part and create a worksheet drawing object.
4. Add an image part to the drawings part and load the image (certificate) from a file or a stream.
5. Add a non-visual drawing properties object to the worksheet drawing object and set its attributes, such as id, name, and description.
6. Add a picture object to the worksheet drawing object and set its attributes, such as id, name, and description.
7. Add a shape properties object to the picture object and set its transform properties, such as offset and extent.
8. Add a picture fill object to the shape properties object and set its image reference.
9. Add a two-cell anchor object to the worksheet drawing object and set its attributes, such as editAs, from, and to.
10. Append the picture object to the two-cell anchor object and append the two-cell anchor object to the worksheet drawing object.

The following code snippet illustrates how to implement these steps using OpenXML: