Linq学习一

ASPX

<asp:GridView ID="GridView1" runat="server" AllowPaging="True" AllowSorting="True" AutoGenerateColumns="False" DataKeyNames="Id" DataMember="DefaultView" DataSourceID="LinqDataSource1"> <Columns> <asp:CommandField ShowDeleteButton="True" ShowEditButton="True" /> <asp:BoundField DataField="Id" HeaderText="Id" InsertVisible="False" SortExpression="Id" /> <asp:BoundField DataField="Name" HeaderText="Name" SortExpression="Name" /> <asp:BoundField DataField="Age" HeaderText="Age" SortExpression="Age" /> <asp:BoundField DataField="Class" HeaderText="Class" SortExpression="Class" /> </Columns> </asp:GridView> <asp:LinqDataSource ID="LinqDataSource1" runat="server" ContextTypeName="SampleDataContext" EnableDelete="True" EnableInsert="True" EnableUpdate="True" TableName="UseForm"> <UpdateParameters> <asp:Parameter Name="@Id" /> <asp:Parameter Name="@Name" /> <asp:Parameter Name="@Age" /> <asp:Parameter Name="@Class" /> </UpdateParameters> </asp:LinqDataSource> </div> <asp:GridView ID="GridView2" runat="server"> </asp:GridView> <br /> <asp:GridView ID="GridView3" runat="server"> </asp:GridView>

 

CS

protected void Page_Load(object sender, EventArgs e) { SampleDataContext sdc=new SampleDataContext(); var query = from mysdc in sdc.UseForm where mysdc.Name == "尹红伟" select mysdc.Name; //from 变量名 in 建立的.dbml对象的表对象 where 变量名.属性 select 重新组合显示字段。 GridView2.DataSource=query; GridView2.DataBind(); var query2 = from mysdc2 in sdc.UseForm where mysdc2.Name == "尹红伟" select new {mysdc2.Name,mysdc2.Age }; GridView3.DataSource = query2; GridView3.DataBind(); //变量名query 和query2都不能覆盖赋值。 }

 

Browser View

 

所有的LINQ查询基本上都是由3个基本的操作组成：得到数据源，创建查询和执行查询3个过程。数据的获得是在执行查询的时候完成的。