Form should not be shown after raising an error

Hi all i have written the following code

private void btnEntry_Click(object sender, EventArgs e)
        {

            if (cmbServiceClassCode.SelectedIndex == -1 || txtCompname.Text == string.Empty || txtCompidentification.Text == string.Empty
                || cmbStandardentryclasscode.SelectedIndex == -1 || txtOrgstatuscode.Text == string.Empty || txtODFIidentification.Text == string.Empty
                || txtBatchno.Text == string.Empty)
            {
                MessageBox.Show("Insufficient Data to Proceed");
                if (Convert.ToBoolean(DialogResult.OK))
                {
                    this.Show();
                }
            }

            string s = cmbStandardentryclasscode.SelectedItem.ToString();
            try
            {

                if (s == "CCD")
                {
                    frmEntryDetails frmentry = new frmEntryDetails(s);
                    frmentry.ShowDialog(this);
                }
                else
                {
                    frmEntryDetails frmentry = new frmEntryDetails(s);
                    frmentry.ShowDialog(this);
                }
            }


            catch (Exception ex)
            {

            }

        }

But if i select some value cmbStandardentryclasscode the error message is displayed but executing the remaining code. So can any one please help me.