OpenXML SDK Inject VBA into excel workbook

Question

I can successfully inject a piece of VBA code into a generated excel workbook, but what I am trying to do is use the Workbook_Open() event so the VBA code executes when the file opens. I am adding the sub to the "ThisWorkbook" object in my xlsm template file. I then use the openxml productivity tool to reflect the code and get the encoded VBA data.

When the file is generated and I view the VBA, I see "ThisWorkbook" and "ThisWorkbook1" objects. My VBA is in "ThisWorkbook" object but the code never executes on open. If I move my VBA code to "ThisWorkbook1" and re-open the file, it works fine. Why is an extra "ThisWorkbook" created? Is it not possible to inject an excel spreadsheet with a Workbook_Open() sub? Here is a snippet of the C# code I am using:

private string partData = "...";  //base 64 encoded data from reflection code
//open workbook, myWorkbook
VbaProjectPart newPart = myWorkbook.WorkbookPart.AddNewPart<VbaProjectPart>("rId1");
System.IO.Stream data = GetBinaryDataStream(partData);
newPart.FeedData(data);
data.Close();
//save and close workbook

Anyone have ideas?

Answer 1

Based on my research there isn't a way to insert the project part data in a format that you can manipulate in C#. In the OpenXML format, the VBA project is still stored in a binary format. However, copying the VbaProjectPart from one Excel document into another should work. As a result, you'd have to determine what you wanted the project part to say in advance.

If you are OK with this, then you can add the following code to a template Excel file in the 'ThisWorkbook' Microsoft Excel Object, along with the appropriate Macro code:

Private Sub Workbook_Open()
    Run "Module1.SomeMacroName()"
End Sub

To copy the VbaProjectPart object from one file to the other, you would use code like this:

public static void InsertVbaPart()
{
    using(SpreadsheetDocument ssDoc = SpreadsheetDocument.Open("file1.xlsm", false))
    {
        WorkbookPart wbPart = ssDoc.WorkbookPart;
        MemoryStream ms;
        CopyStream(ssDoc.WorkbookPart.VbaProjectPart.GetStream(), ms);

        using(SpreadsheetDocument ssDoc2 = SpreadsheetDocument.Open("file2.xlsm", true))
        {
            Stream stream = ssDoc2.WorkbookPart.VbaProjectPart.GetStream();
            ms.WriteTo(stream);
        }
    }
}

public static void CopyStream(Stream input, Stream output)
{
    byte[] buffer = new byte[short.MaxValue + 1];
    while (true)
    {
        int read = input.Read(buffer, 0, buffer.Length);
        if (read <= 0)
            return;
        output.Write(buffer, 0, read);
    }
}

Hope that helps.