出现错误未将对象引入到实例上

string strConn = "Data Source=(local);";
        strConn += "Initial Catalog=FPCOGIS;";
        strConn += "user ID=sa;";
        strConn += "Password=;";
        string strSQL = "select * from tbCoorperationOrg where sCoOrName="+"'"+name+"'";
        DataSet moDS = new DataSet();
        SqlDataAdapter oAdapter = new SqlDataAdapter(strSQL, strConn);
        oAdapter.Fill(moDS, "CoorperationOrg");
        moDS.Tables["CoorperationOrg"].PrimaryKey = new DataColumn[] { moDS.Tables["CoorperationOrg"].Columns["iCoOrID"] };
      
        gv.DataSource = moDS.Tables["CoorperationOrg"];
        gv.DataBind();
gv为GridView控件,这样写有什么问题,老是提示错误,
提示未将对象引用设置到对象的实例