Как сравнить два datatgridviews и получить разницу в datagridview3 ?

---

DataGridView1 has list of software in Column Installed_Software, and 
DataGridView2 has a list of Installed_Software. I want DataGridView2 Installed_Software Column Compared to DataGridView1 Installed_Software Column,
and what Installed_Software DataGridView2 has that DataGridView1 does not have, I want Displayed in DataGridView3. If no Difference between the DGV1 and DGV2, then have MessageBox say something like Match.

Что я уже пробовал:

Ниже показано, как DataGridViews 1 и 2 заполняются столбцами Domain_User, Installed_Software:

dgv1 = DataGridView1 and dgv2 = DataGridView2 in the Code below.
  
 con = new SqlConnection();
            con.ConnectionString = @"Data Source=STACYWLENOVO; Initial Catalog=SoftwareHardwareTracking; Integrated Security=TRUE";

            con.Open();
            adp = new SqlDataAdapter("select Domain_User, Installed_Software from tblBkupSoftwareCount", con);
            ds1 = new System.Data.DataSet();
            adp.Fill(ds1, "Client Details");
            dgv2.DataSource = ds1.Tables[0];
            // https://stackoverflow.com/questions/8983277/how-to-convert-dataset-to-datatable
            //Code below to get dataset into DataTable dt2
            DataTable dt2 = ds1.Tables[0];
            con.Close();


            //Code pulling tblSoftwareCount
            conn = new SqlConnection();
            conn.ConnectionString = @"Data Source=STACYWLENOVO; Initial Catalog=SoftwareHardwareTracking; Integrated Security=TRUE";

            conn.Open();
            adap = new SqlDataAdapter("select Domain_User, Installed_Software from tblSoftwareCount", conn);
            ds = new System.Data.DataSet();
            adap.Fill(ds, "Client Details");
            dgv1.DataSource = ds.Tables[0];
            //https://stackoverflow.com/questions/8983277/how-to-convert-dataset-to-datatable
            //Code below to get dataset into DataTable dt1
            DataTable dt1 = ds.Tables[0];
            conn.Close();


            dt3 = (dt1, dt2);

              if (dt.Rows.Count == 0)
                 
                    MessageBox.Show("Equal");
               else

              MessageBox.Show("Not Equal");

---