Adiciona novo campo, via AO, em tabela registrada

AddField.cs

        private static void AdicionarCampo(IWorkspace workspace)
        {
            var table2AddField = ((IFeatureWorkspace)workspace).OpenTable("TESTE_A");

            var schemaLock = (ISchemaLock)table2AddField;
            try
            {
                schemaLock.ChangeSchemaLock(esriSchemaLock.esriExclusiveSchemaLock);

                var newField = new FieldClass();
                var field = (IFieldEdit2)newField;
                field.Name_2 = "NovoCampo";
                field.Type_2 = esriFieldType.esriFieldTypeString;
                field.Length_2 = 50;
                field.DefaultValue_2 = "Teste";

                table2AddField.AddField(newField);
            }
            finally
            {
                schemaLock.ChangeSchemaLock(esriSchemaLock.esriSharedSchemaLock);
            }
        }