private void button1_Click(object sender, EventArgs e) { if (!string.IsNullOrEmpty(textBox1.Text) && comboBox2.SelectedItem != null) { QuestionSet questionSet = client.RetrieveQuestionSetByTitle(comboBox2.Text); client.CreateGame2(new Game { Name = textBox1.Text }, questionSet.Title, Int32.Parse(maskedTextBox1.Text)); Game game = client.RetrieveGame(textBox1.Text, false);; client.AddPlayer(game); this.Hide(); (new Lobby(game, client)).Show(); } else { MessageBox.Show("All fields must be filled!", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error); } }