private async void educationRemove_Click(object sender, EventArgs e) { if (TeacherListView.SelectedCells.Count == 0) { return; } var teacher = ((List <Teacher>)TeacherListView.DataSource)[TeacherListView.SelectedCells[0].RowIndex]; if (educationGridView.SelectedCells.Count == 0) { return; } var education = ((List <DomainClasses.Main.Education>)educationGridView.DataSource)[educationGridView.SelectedCells[0].RowIndex]; eduRepo.delete(education.id); UpdateEducationList(teacher.id); }