Force “Minor check in” when (instead of) “Major check in” occurs

Question

I am playing around with SPItemEventProperties and it looks like it's little bit messed up (or I am totally missing the point).

Here is what I am trying to do. When a user do a "Major check in" I simply change it to a "Minor check in". No pop-ups, no magic, I am just trying to do this as simple as possible by changing the SPItemEventProperties.AfterProperties["vti_level"] to "255" when it's set to "1" (this link explains check in values). However I didn't find any successful solution so far. I already tried in ItemUpdating, ItemUpdated, ItemCheckingIn, ItemCheckedIn and nothing...

The user flow is the following:

• User right click (or SharePoint dropdown) on a document and select "Check Out"
• Popup shows up saying "you are about to check out, blah blah blah, Use local Drafts?" The user will check "Use local drafts folder" and press "Ok"
• Document was checked out, now the user will try to check in as Major version
• The user successfully checks in the document, but as a "Minor version" instead of "Major version"

The simplified code looks like:

public override void ItemUpdating(SPItemEventProperties properties) {
    foreach (DictionaryEntry de in properties.AfterProperties)
    {
        string key = de.Key.ToString();
        string value = de.Value.ToString();
        //If the document is about to be published (made a major version) ...
        if (key.Equals("vti_level") && value.Equals("1"))
        {
            //set as minor version
            properties.AfterProperties["vti_level"] = "255";
        }
    }
}

(This my sound a bit stupid, but I added a library property to "Prevent Major check ins" and that's why I am trying to do this)

Answer 1

My first instinct after hearing the problem is to go to the ItemCheckedIn method, and if it was a major check in, check it out and check it in again as a minor check in. Alternatively, attach to the ItemCheckingIn event, and if it's a major check in cancel the event and (with event firing disabled) check the item in as a minor check in.