问题
When I am databinding an entire page, I will do something like this:
Blah blah...
<%# SomeProperty == "GoodBye" ? "See you later" : "Hello" %>
And that works beatifully. However, often I will not use databinding for an entire page and write things the "clasic" ASP.NET way. E.g., in the code behind I will have something like:
lblSomeMessage.Text = SomeProperty == "GoodBye" ? "See you later" : "Hello";
And then .aspx would have
<asp:label runat="server" id="lblSomeMessage"/>
But what I want to do both...sort of. What I would like to do is not use databinding syntax but instead a code block:
<%= SomeProperty == "GoodBye" ? "See you later" : "Hello" %>
^^^^
Noe the output tag syntax. Now, the question is, when will this tag actually be evaluated? Suppose I don't set the SomeProperty property until the OnPreRender event. Is that too late? In my testing I actually did this:
<%= SomeProperty == "GoodBye" ? + new System.Diagnostics.StackTrace().ToString() : "OH NO!" %>
And according to the stacktrace:
ASP.webform1_aspx.__Renderform1(HtmlTextWriter __w, Control parameterContainer) at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) at System.Web.UI.HtmlControls.HtmlForm.RenderChildren(HtmlTextWriter writer)...
It happens during render, which is perfect. But is this guaranteed? Any gotchas to this rule?
回答1:
Yes, it's guaranteed to be Render.
"An embedded code block is server code that executes during the page's render phase." - http://msdn.microsoft.com/en-us/library/ms178135.aspx
来源：https://stackoverflow.com/questions/7251330/when-are-asp-net-code-blocks-e-g-executed-in-the-page-lifecycle