DataRow drT = null;
DataTable dt1 = new DataTable();
dt1.Columns.Add("Column1");
drT = dt1.NewRow();
drT["Column1"] = "value 1";
dt1.Rows.Add(drT);
drT = dt1.NewRow();
drT["Column1"] = "value 2";
dt1.Rows.Add(drT);
drT = dt1.NewRow();
drT["Column1"] = "value 3";
dt1.Rows.Add(drT);
drT = dt1.NewRow();
drT["Column1"] = "value 4";
dt1.Rows.Add(drT);
DataTable dt2 = new DataTable();
dt2.Columns.Add("Column1");
drT = dt2.NewRow();
drT["Column1"] = "value 1";
dt2.Rows.Add(drT);
drT = dt2.NewRow();
drT["Column1"] = "value 2";
dt2.Rows.Add(drT);
drT = dt2.NewRow();
drT["Column1"] = "value 5";
dt2.Rows.Add(drT);
drT = dt2.NewRow();
drT["Column1"] = "value 6";
dt2.Rows.Add(drT);
IEnumerable<DataRow> ieDrDt1 = dt1.AsEnumerable();
IEnumerable<DataRow> ieDrDt2 = dt2.AsEnumerable();
var exceptData = ieDrDt1.Except(ieDrDt2, DataRowComparer.Default);
foreach (DataRow dr in exceptData)
{
Response.Write(dr["Column1"].ToString() + "<br />");
}