如果表模式相同，则可以在代码中使用Marge方法。而不是将表添加到您的数据集。

If table schema is same you can use Marge method in your code. than add table to your data-set.

 DataTable ONdt = new DataTable();
 DataTable OFFdt = new DataTable();
string strsql = "SELECT * FROM **serverA_table**";
           ONda = new SqlDataAdapter(strsql, ONcon);
           ONds = new DataSet();
           ONda.Fill(ONdt);


           strsql = "SELECT * FROM serverB_table";
           OFFda = new SqlDataAdapter(strsql, OFFcon);
           OFFds = new DataSet();
           OFFda.Fill(OFFdt);
OFFdt.Merge(ONdt);
// Than add it to your Dataset 
OFFds.Tables.Add(OFFdt);