I'm creating an AddIn (using VS2005) and need to be able to exclude
files that exist in the solution and would appreciate some example code
demonstrating this or some suggestions on what to do.

Here's what I have so far:  A Project object (obtained from
DTE.Solution.Projects) has a project.ProjectItems.AddFromFile() method
but there isn't a project.ProjectItems.RemoveFile() method.  I've
searched the DTE, Solution, Project, and ProjectItem classes and if one
of these classes has the ability to remove a file, I've missed it.

I'd _MUCH_ prefer a programmatic way of excluding a file, but I'd settle
 using dte2.ExecuteCommand(), but I'm not getting the syntax with
ExecuteCommand() correct.  So far, I've tried:

// the full path to the source file
ExecuteCommand("Project.ExcludeFromProject", @"C:\MyPrj\MySource.cs");

// just the name of the source file
ExecuteCommand("Project.ExcludeFromProject", "MySource.cs");

// and "" and null
ExecuteCommand("Project.ExcludeFromProject", "");
ExecuteCommand("Project.ExcludeFromProject", null);

But all four throw a COMException
"Error HRESULT E_FAIL has been returned from a call to a COM component."

ErrorCode = -2147467259;

I looked up this error with errlook.exe and it reported that -2147467259
is "Unspecified error".  Cool.

So, if anyone has any experience with this or ant suggestions on what to
do, I'd appreciate it.

TIA.

-Jay