没有Page的ASP.NET IsPostBack

Question

Is there a way I can find out if a Page has been posted back without using the Page object. I want to know if the page has been posted back without passing a parameter to the function, like you can check the Request object by using httpContext.Current.Request , is there a Page equivalent? The check occurs in a library function?

Answer 1

如果您只是试图避免使用Page属性而不是Page类，则可以在标准页面请求的上下文中将HttpContext.Current.Handler强制转换为Page对象。

Answer 2

Here's another technique. You can get the Page from HttpContext, and check its IsPostBack method. That way you don't have to pass the page or an IsPostBack flag to your helper function.

void MyHelperFunction()
{   
    Page page = HttpContext.Current.Handler as Page;
    bool isPostBack = (page != null) && (page.IsPostBack);
}

Answer 3

Yep

1. Check to see if the HTTP verb is POST
2. Check the Forms collection for a value associated with "__PREVIOUSPAGE"

See also here