gridview 级联删除、dataset

gridview编辑列（不使用控件绑定数据源）
需要如下代码：
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False">
    <Columns>
        <asp:TemplateField HeaderText="类别ID"><ItemTemplate><%# Eval("ID") %></ItemTemplate></asp:TemplateField>
        <asp:TemplateField HeaderText="类别名"><ItemTemplate><%# Eval("CaName") %></ItemTemplate></asp:TemplateField>
    </Columns>
  </asp:GridView>
在gridview标签中，设置AutoGenerateColumns="False"，最主要的就是<%# Eval("ID") %>，gridview中“类别ID”这一列的值，取表中ID这一列的值

表的级联删除
二级删除触发器：
CREATE TRIGGER deleteCategory ON category
INSTEAD OF  DELETE
AS
DECLARE @id int;  
SELECT @id=ID from deleted;
DELETE FROM Subject
WHERE CaID=@id;
DELETE FROM Category
WHERE ID=@id;
三级删除触发器：
create trigger delCategory on Category
instead of delete
as
declare @caid int
select @caid=ID from deleted
--删除评论
delete from Restore where SubjID in (select ID from Subject where CaID=@caid) --in是关键，是包含关系，所有CaID=@caid的主题的ID都会被选出。
--删除主题
delete from Subject where CaID=@caid
--删除类别
delete from Category where ID=@caid

添加数据集：
添加数据集，添加tableadapter，添加查询语句，然后可直接调用adapter的各种方法。
例如：
DataSet1TableAdapters.CategoryTableAdapter dtdCa = new DataSet1TableAdapters.CategoryTableAdapter();
    DataSet1.CategoryDataTable dtblCa = new DataSet1.CategoryDataTable();
 dtdCa.Fill(dtblCa);
        GridView1.DataSource = dtblCa;
        GridView1.DataBind();