//--- update course
private void button2_Click(object sender, EventArgs e)
{
try
{
string crsname = textBox1.Text;
int crsid = (int)comboBox1.SelectedItem;
using (Online_Exame ent = new Online_Exame())
{
ent.UpdateCourse(crsid, crsname);
ent.SaveChanges();
}
MessageBox.Show("Updated Successfully");
Courses.Items.Clear();
Instructors.Items.Clear();
label7.Text = comboBox1.Text = comboBox3.Text = textBox1.Text = string.Empty;
LoadCourses();
}
catch (NullReferenceException)
{
MessageBox.Show("Not complete Form");
}
}