Preserving the last “Modified By” when checking in a file

I’ve heard people saying that you cannot check in a file specifying explicitely who the “Modified By” user should be. Actually this is not true and you can do this easily through the object model using reflection and the code below:

public static void CheckInFileByUser(

    SPFile file,

    string checkinComment,

    SPCheckinType checkinType,

    SPUser modifiedByUser)

{

    MethodInfo mi = typeof(SPFile).GetMethod(

        “CheckIn”,

        BindingFlags.Instance | BindingFlags.NonPublic,

        null,

        new Type[] { typeof(string), typeof(SPCheckinType), typeof(bool), typeof(SPUser) },

        null);

 

    try

    {

        mi.Invoke(

            file,

            new object[] { checkinComment, checkinType, false, modifiedByUser }

        );

    }

    catch (TargetInvocationException invokeEx)

    {

        throw invokeEx.InnerException;

    }

}

Before calling this code you should check-out the file. If you don’t do so it will rethrow the “The file …. is not checked out.” SPException which will be thrown by SharePoint. The code will also bring all other SharePoint exceptions to you. And of course if you want to preserve the last “Modified By” user when updating your file using this function, just pass the file.ModifiedBy as the user argument retrieved before the file was checked out.