How can I refresh combobox value after the instulation of the application?

private void button3_Click(object sender, EventArgs e)
        {
            try
            {
                state = "add";
                DataTable Dt = new DataTable();
                Dt = CBE.VerifyCrime(textBox1.Text);
                if (Dt.Rows.Count > 0)
                {
                    MessageBox.Show("DUBLICATION", "RECORD DUBLICATED", MessageBoxButtons.OK, MessageBoxIcon.Warning);
                    textBox1.Focus();
                    textBox1.SelectionStart = 0;
                    textBox1.SelectionLength = textBox1.TextLength;
                    return;
                }
                CBE.addcrime(textBox1.Text);
                MessageBox.Show("NEW CRIMINAL BEHAVIOR ADDED ", "ADD", MessageBoxButtons.OK, MessageBoxIcon.Information);
                this.dataGridView1.DataSource = CBE.getallgridview();

                FRM_SUSPECT.getMainForm.CBOBOX.DataSource = sus.Getallcrimebehaviour();
                FRM_SUSPECT.getMainForm.CBOBOX.SelectedIndex = -1;

                FRM_SUSPECT.getMainForm.CBOBOX2.DataSource = sus.Getallcrimebehaviour();
                FRM_SUSPECT.getMainForm.CBOBOX2.SelectedIndex = -1;
            }
            catch
            {
                MessageBox.Show("error");
                return;
            }
        }