Page 生命週期

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週五, 2015-07-24 11:10
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Page 生命週期
► ASP.NET 應用程式生命週期概觀
 
► page載入時相關被呼叫的事件 
protected void Page_PreInit(object sender, EventArgs e)  {
    Response.Write("1 Master Page_PreInit" + "<br/>");
}
protected void Page_Init(object sender, EventArgs e) {
    Response.Write("2 Master Page_Init" + "<br/>");
}
protected void Page_InitComplete(object sender, EventArgs e) {
    Response.Write("3 Master Page_InitComplete" + "<br/>");
}
protected void Page_PreLoad(object sender, EventArgs e) {
    Response.Write("4 Master Page_PreLoad" + "<br/>");
}
protected void Page_Load(object sender, EventArgs e) {
    Response.Write("5 Master Page_Load" + "<br/>");
}
protected void Page_LoadComplete(object sender, EventArgs e) {
    Response.Write("6 Master Page_LoadComplete" + "<br/>");
}
protected void Page_PreRender(object sender, EventArgs e) {
    Response.Write("7 Master Page_PreRender" + "<br/>");
}
protected void Page_PreRenderComplete(object sender, EventArgs e) {
    Response.Write("8 Master Page_PreRenderComplete" + "<br/>");
}
protected void Page_SaveStateComplete(object sender, EventArgs e) {
    Response.Write("9 Master Page_SaveStateComplete" + "<br/>");
}
protected void Page_Render(object sender, EventArgs e) {
    Response.Write("10 Master Page_Render" + "<br/>");
}
protected void Page_Unload(object sender, EventArgs e) {
    //Response.Write("Page_Unload" + "<br/>");
}
► 觸發情況

在Default.aspx中的後置程式碼中，以如同上的作法，建立出事件區塊，輸出識別用的字串
執行Default.aspx後結果如下 :

1 Sub Page_PreInit
2 Master Page_Init
2 Sub Page_Init
3 Sub Page_InitComplete
4 Sub Page_PreLoad
5 Sub Page_Load
5 Master Page_Load
6 Sub Page_LoadComplete
7 Sub Page_PreRender
7 Master Page_PreRender
8 Sub Page_PreRenderComplete
9 Sub Page_SaveStateComplete

結果頗令人玩味，在Sub Page_PreInit時，就會先設定主版頁面，然後觸發Master Page_Init、Sub Page_Init。而Load、PreRender事件剛好相反，是由Sub Page先觸發。而再把實驗升級，在MasterPage與Default.aspx中各加入一個Button控制項，並在Button Click事件中輸出識別用的字串。
執行後點選MasterPage中的Button，輸出結果如下:

1 Sub Page_PreInit
2 Master Page_Init
2 Sub Page_Init
3 Sub Page_InitComplete
4 Sub Page_PreLoad
5 Sub Page_Load
5 Master Page_Load
Master Page Button1_Click
6 Sub Page_LoadComplete
7 Sub Page_PreRender
7 Master Page_PreRender
8 Sub Page_PreRenderComplete
9 Sub Page_SaveStateComplete

而點選Default.aspx的Button後輸出結果如下:

1 Sub Page_PreInit
2 Master Page_Init
2 Sub Page_Init
3 Sub Page_InitComplete
4 Sub Page_PreLoad
5 Sub Page_Load
5 Master Page_Load
Sub Page Button1_Click
6 Sub Page_LoadComplete
7 Sub Page_PreRender
7 Master Page_PreRender
8 Sub Page_PreRenderComplete
9 Sub Page_SaveStateComplete

根據MSDN文件描述，網頁中的控制項事件是在Load之後所引發，而加了MasterPage的網頁，也會等到MasterPage的Load事件之後才引發一般頁面上的控制項事件。



from ASP.NET 網頁存留週期概觀 , Page Life Cycle Overview ,
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