合并两个DataTable

SqlConnection myConnection=new SqlConnection("server=localhost;uid=sa;pwd=;database=wjoa");
            string sql1="select * from ResourseManage_T";
            SqlDataAdapter adapterA=new SqlDataAdapter(sql1,myConnection);
            DataSet ds=new DataSet();
            adapterA.Fill(ds,"a");
            string sql2="select * from UserLogin_t";
                
            if(myConnection.State != ConnectionState.Closed)
            myConnection.Close();
            adapterA=new SqlDataAdapter(sql2, myConnection);
            adapterA.Fill(ds,"b");
            DataTable dtParent=ds.Tables["a"];
            DataTable dtChild=ds.Tables["b"];
            DataRow dr;
            for(int i=0;i<dtChild.Rows.Count;i++)
            {     
                dr=dtParent.NewRow();
                for(int j=0;j<dtParent.Columns.Count;j++)
                {
                    dr[j]=dtChild.Rows[i][j];
                }
                dtParent.Rows.Add(dr);
            }
            this.DataGrid1.DataSource=ds.Tables["a"].DefaultView;
            this.DataGrid1.DataBind();