Quote:
i want to transfer all the data from dt_vendor to dataset ds["vendor"]
I am interpreting this a bit differently than the others have and assume that you literally want to transfer each row from dt_vendor into a table named "vendor" in the dataset "ds".
for (int i = dt_vendor.Rows.Count - 1; i > -1; i -= 1)
{
ds.Tables["vendor"].ImportRow(dt_vendor.Rows[i]);
dt_vendor.Rows[i].Delete();
}