public int AddHandler(string bstrEventName)
        {
            var node          = LookupNode();
            var semanticModel = GetSemanticModel();

            FileCodeModel.PerformEdit(document =>
            {
                return(CodeModelService.AddHandlesClause(document, bstrEventName, node, CancellationToken.None));
            });

            return(VSConstants.S_OK);
        }