ASP.NET

ASP.NET 学习二 内容摘自msdn收藏 How to: Determine How ASP.NET Web Pages Were Invoked

The following table lists ways in which a page can be invoked and the
corresponding Page property values.

Invocation method

Property values

Original request

・ IsPostBack is set to false.

・ PreviousPage is set to null (Nothing in Visual Basic).

・ IsCallback is set to false.

Postback

・ IsPostBack is set to true.

・ PreviousPage is set to null (Nothing in Visual Basic).

・ IsCallback is set to false.

Cross-page posting

・ IsPostBack is set to false.

・ PreviousPage references the source page.

・ IsCrossPagePostBack is set to true.

・ IsCallback is set to false.

Server transfer

・ IsPostBack is set to false.

・ PreviousPage references the source page.

・ IsCrossPagePostBack that is referenced in the PreviousPage is set to false.

・ IsCallback is set to false.

Callback

・ IsPostBack is set to false.

・ PreviousPage is set to null (Nothing in Visual Basic).

・ IsCallback is set to true.