ASP.NET中使用数据处理插入数据注意的问题

很多时候，我们都会习惯将数据库连接的初始化过程交给Page_Load去做，其实这样子有好处也有坏处，好处是单边问题的时候，这种方法很实用，坏处就是遇到多边的问题时，就种情况这不太好用了！例如下面的例子：

///ForExample: <scriptlanguage="C#"runat="server"> SqlConnectionmySqlCon; protectedvoidPage_Load(ObjectSrc,EventArgsE) { mySqlCon=newSqlConnection("server=localhost;uid=sa;pwd=sa;database=pubs");//初始化过程 if(!IsPostBack) BindGrid(); } publicvoidAddPublisher(Objectsender,EventArgsE) { StringmyinsertCmd="insertintopublishers(pub_id,pub_name,city,state,country)values(@pubid,@pubname,@city,@state,@country)"; SqlCommandmySqlCom=newSqlCommand(myinsertCmd,mySqlCon);//初始化命令调用 //实现配套 mySqlCom.Parameters.Add(newSqlParameter("@pubid",SqlDbType.Char,4)); mySqlCom.Parameters["@pubid"].Value=Pub_Id.Text; mySqlCom.Parameters.Add(newSqlParameter("@pubname",SqlDbType.VarChar,40)); mySqlCom.Parameters["@pubname"].Value=Pub_Name.Text; mySqlCom.Parameters.Add(newSqlParameter("@city",SqlDbType.VarChar,20)); mySqlCom.Parameters["@city"].Value=City.Text; mySqlCom.Parameters.Add(newSqlParameter("@state",SqlDbType.Char,2)); mySqlCom.Parameters["@state"].Value=State.Text; mySqlCom.Parameters.Add(newSqlParameter("@country",SqlDbType.VarChar,30)); mySqlCom.Parameters["@country"].Value=Country.Text; //打开DB mySqlCom.Connection.Open(); mySqlCom.ExecuteNonQuery(); Message.InnerHtml="<b>已添加记录</b><br/>"; mySqlCom.Connection.Close(); Pub_Id.Text=""; Pub_Name.Text=""; City.Text=""; State.Text=""; Country.Text=""; BindGrid(); } //子函数调用 publicvoidBindGrid() { SqlDataAdaptermySqlCom=newSqlDataAdapter("select*frompublisherswherepub_idlike'99%'",mySqlCon); DataSetmyds=newDataSet(); mySqlCom.Fill(myds,"publishers"); dgMyGrid.DataSource=myds.Tables["publishers"].DefaultView;dgMyGrid.DataBind(); } </script> <h2>添加一个新的发行者：</h2> <br/> 发行者ID应以99打头，并包含4位数字<br/> 发行者ID：&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <asp:textboxrunat="server"/>姓名：&nbsp;&nbsp; <asp:textboxrunat="server"/> 城市：&nbsp; <asp:textboxrunat="server"/> <br/> 省：&nbsp; <asp:textboxrunat="server"/> 国家：&nbsp; <asp:textboxrunat="server"/> <br/> <br/> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <asp:buttonText="提交"OnClick="AddPublisher"runat="server"ID="Button1"/><br/> <spanrunat="server"/> <br/> <asp:DataGridrunat="server"/>

这样的例子初初看起来没有问题，调试也没报错，但在生成的页面添加数据后提交时就会报错，说什么属性不配套之类的话。是什么原因造成的呢！其实，这就是初始化过程在页面装载时造成的，但这里有个问题我始终没能搞清楚，就是既然是在页面初始化过程已经初始化过DB实例了，按道理来讲应该可以直接生成套用的啊，但好像没有！还是要把初始化过程放到具体的函数里面才能实现！看下面:

<<scriptlanguage="C#"runat="server"> protectedvoidPage_Load(ObjectSrc,EventArgsE) { //页面装载过程中直接使用IF语句，其实什么也不加！ if(!IsPostBack) BindGrid(); } publicvoidAddPublisher(Objectsender,EventArgsE) { stringstrprovider="server=localhost;uid=sa;pwd=sa;database=pubs";//构造初始化过程 SqlConnectionmySqlCon=newSqlConnection(strprovider); stringmyinsertCmd="insertintopublishers(pub_id,pub_name,city,state,country)values(@pubid,@pubname,@city,@state,@country)"; SqlCommandmySqlCom=newSqlCommand(myinsertCmd,mySqlCon);//初始化过程实现 mySqlCom.Parameters.Add(newSqlParameter("@pubid",SqlDbType.Char,4)); mySqlCom.Parameters["@pubid"].Value=Pub_Id.Text; mySqlCom.Parameters.Add(newSqlParameter("@pubname",SqlDbType.VarChar,40)); mySqlCom.Parameters["@pubname"].Value=Pub_Name.Text; mySqlCom.Parameters.Add(newSqlParameter("@city",SqlDbType.VarChar,20)); mySqlCom.Parameters["@city"].Value=City.Text; mySqlCom.Parameters.Add(newSqlParameter("@state",SqlDbType.Char,2)); mySqlCom.Parameters["@state"].Value=State.Text; mySqlCom.Parameters.Add(newSqlParameter("@country",SqlDbType.VarChar,30)); mySqlCom.Parameters["@country"].Value=Country.Text; mySqlCom.Connection.Open(); mySqlCom.ExecuteNonQuery(); Message.InnerHtml="<b>已添加记录</b><br>"; mySqlCom.Connection.Close(); Pub_Id.Text=""; Pub_Name.Text=""; City.Text=""; State.Text=""; Country.Text=""; BindGrid(); } publicvoidBindGrid()子函数调用时同样也要初始化DB连接 { stringstrprovider="server=dev;uid=sa;pwd=pauperboyboy;database=pubs"; SqlConnectionmySqlCon=newSqlConnection(strprovider); SqlDataAdaptermySqlCom=newSqlDataAdapter("select*frompublisherswherepub_idlike'99%'",mySqlCon); DataSetmyds=newDataSet(); mySqlCom.Fill(myds,"publishers"); dgMyGrid.DataSource=myds.Tables["publishers"].DefaultView; dgMyGrid.DataBind(); } </script> <h2>添加一个新的发行者：</h2> <br> 发行者ID应以99打头，并包含4位数字<br> 发行者ID：&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <asp:textboxrunat="server"/>姓名：&nbsp;&nbsp; <asp:textboxrunat="server"/> 城市：&nbsp; <asp:textboxrunat="server"/> <br> 省：&nbsp; <asp:textboxrunat="server"/> 国家：&nbsp; <asp:textboxrunat="server"/> <br> <br> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <asp:buttonText="提交"OnClick="AddPublisher"runat="server"ID="Button1"/><br> <spanrunat="server"/> <br> <asp:DataGridrunat="server"/> </form>>

经过这样修改后，我们才能在真正意义上实现数据的增加！