Changing SPField cause no changes

Question

I try to change an SPField after SPList creation, but I'm not getting any results of that change. using this code:

    SPField oSPField = oSPList.Fields[new Guid("MyFieldGuid")];
    oSPField.ReadOnlyField = true;
    oSPField.ShowInEditForm = false;
    oSPField.ShowInNewForm = false;
    oSPField.Update();

and then...nothing happens. What's wrong?is there any change to change it without coding?

(the field CT is provided by an ContentType Hub.)

Answer 1

Since you are effectively changing the list schema, you may have to do an oSPList.Update() as well.