how to stop focus on control

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C#

C#4.0

Hi friends,

The below is my code.

private void comboBox7_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (radioButton2.Checked == true)
            {
                comp.CLASSID = Convert.ToInt32(comboBox2.SelectedValue.ToString());
                comp.ACADAMICYEAR = textBox1.Text;
                comp.MEDIUM = comboBox1.Text;
                comp.SECTIONNAME = Convert.ToChar(comboBox4.Text);
                DataTable studentdet = inter.getstudentlistforclass(comp);
                dataGridView1.DataSource = studentdet;
                DataGridViewTextBoxColumn fourthcolumn = new DataGridViewTextBoxColumn();
                fourthcolumn.HeaderText = comboBox7.Text;
                fourthcolumn.Name = comboBox7.Text;
                dataGridView1.Columns.Add(fourthcolumn);
                
                
            }
        }

private void comboBox6_Leave(object sender, EventArgs e)
       {


           if (radioButton2.Checked == true)
           {
               comp.CLASSID = Convert.ToInt32(comboBox2.SelectedValue.ToString());
               comp.ACADAMICYEAR = textBox1.Text;
               comp.MEDIUM = comboBox1.Text;
               comp.EXAMNAMES = comboBox6.Text;
               DataTable subjectname = inter.getexamnamefordatagridastable(comp);
               comboBox7.DataSource = subjectname;
               comboBox7.DisplayMember = "SubjectName";
               comboBox7.ValueMember = "SubjectCode";
           }
       }

when i working with combobox7_selectedevent, after completing this event it automatically going to combobox6_leave even at the place of

comboBox7.DataSource = subjectname;
                comboBox7.DisplayMember = "SubjectName";
                comboBox7.ValueMember = "SubjectCode";

I dont want to go through this way. i want to stop that focus only in combobox7 event. Is any idea?
Advance Thanks