asp.net - asp.netは現在のユーザーIDを取得します

Question

コードビハインドで私はこれを持っています:

 protected void ButtonSave_Click(object sender, EventArgs e)
        {
            Guid guid = (Guid)Membership.GetUser().ProviderUserKey;
            string name = TextBoxCategoryName.Text;
           // string user = Membership.GetUser().UserName;
            this.connection.Open();
            command = connection.CreateCommand();
            command.CommandText = "insert into ProfitCategories(name, IdUser) values ( '" + name + "', "+guid+" )";
            command.ExecuteNonQuery();

            connection.Close();
        }

しかし、これはエラーを出します: Incorrect syntax near 'a8'. how to get GUID from current user and insert into database