linq to sql插入操作取回自增的ID

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首先我们来看一个简单的插入操作：

<wbr><wbr><wbr><wbr><wbr><wbr><wbr> TestDataContext dc = new TestDataContext();<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> protected void Page_Load(object sender, EventArgs e)<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> {<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr> tbl_User user = new tbl_User();<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr> user.uname = "徐越";<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr> user.upwd = "111";<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr> dc.tbl_User.InsertOnSubmit(user);<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr> dc.SubmitChanges();</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

<wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><strong>int id = user.uid;<br></strong><wbr><wbr><wbr><wbr><wbr><wbr><wbr> }</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

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int id = user.uid 这句话就能拿到刚刚插入的值！这么神奇，为什么呢？

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1 首先我们在数据库中对uid设置的时候，就设置它为主键，然后为表示列，自增长，种子是1，增长量是1等。

2 那么我们把数据表拖到VS上来，我们不只要会拖，还要会看。

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[global::System.Data.Linq.Mapping.ColumnAttribute(Storage="_uid", AutoSync=AutoSync.OnInsert,DbType="Int NOT NULL IDENTITY", IsPrimaryKey=true, IsDbGenerated=true)]
<wbr><wbr>public int uid<br><wbr><wbr>{<br><wbr><wbr><wbr>get<br><wbr><wbr><wbr>{<br><wbr><wbr><wbr><wbr>return this._uid;<br><wbr><wbr><wbr>}<br><wbr><wbr><wbr>set<br><wbr><wbr><wbr>{<br><wbr><wbr><wbr><wbr>if ((this._uid != value))<br><wbr><wbr><wbr><wbr>{<br><wbr><wbr><wbr><wbr><wbr>this.OnuidChanging(value);<br><wbr><wbr><wbr><wbr><wbr>this.SendPropertyChanging();<br><wbr><wbr><wbr><wbr><wbr>this._uid = value;<br><wbr><wbr><wbr><wbr><wbr>this.SendPropertyChanged("uid");<br><wbr><wbr><wbr><wbr><wbr>this.OnuidChanged();<br><wbr><wbr><wbr><wbr>}<br><wbr><wbr><wbr>}<br><wbr><wbr>}</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

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AutoSync=AutoSync.OnInsert 表示在插入式自动同步，

IsDbGenerated表示是数据库自动生成的值。

这样才能那么神奇！懂了吧。

我们当然也可以通过可视化视图来设置这些属性。

如果是纯sql获得这个id就复杂一点，请参看本博客另一篇：

《Sql Server中如何取得刚刚插入的自增长的id值》

http://blog.sina.com.cn/s/blog_67aaf4440100w7ns.html