Linq to DataSet查询

首先手动建个DataSet

public DataSet BulidDataSet()
        {
            DataSet ds=new DataSet();
            DataTable dt = new DataTable();
            DataColumn col = new DataColumn("姓名",typeof(string));
            col.MaxLength = 20;
            dt.Columns.Add(col);                   //注意是dt.columns 然后ADD
            DataColumn col1 = new DataColumn("年龄", typeof(int));
            col.MaxLength = 20;
            dt.Columns.Add(col1);
            DataRow rw =dt.NewRow();          //给DT增加一个新行对象
            rw["姓名"] = "aking";
            rw["年龄"] = 26;
            dt.Rows.Add(rw);                         //   dt.Rows.Add(dt.NewRow());   增加一个空
            DataRow rw1 = dt.NewRow();
            rw1["姓名"] = "yao";
            rw1["年龄"] = 26;
            dt.Rows.Add(rw1);
            DataRow rw2 = dt.NewRow();
            rw2["姓名"] = "Ayao";
            rw2["年龄"] = 26;
            dt.Rows.Add(rw2);
            ds.Tables.Add(dt);
            return ds;
        }
   Linq查询部分
DataTable persons=ds.Tables[0];
  var num1=from p in persons.AsEnumerable() where p.Field<int>("姓名") ==“yao”
                     select new {
                         ID=p.Field<int>("ID")
        };