ViewState in ASP.NET

SetupStateViewState to set in controls, pages, programs, global configurations. By default EnableViewState is True. If all page viewState features are prohibited, you can set EnableViewState to false in the program configuration. In the control:

or

DataGrid1.enableViewState = false;

On page:

<% @ Page EnableViewState = "false"%>

or

Page.enableViewState = false;

In the program:

Join in Web.config

In the global configuration:

Modify EnableViewState priority: Global Configuration

Note: The following server controls cannot disable ViewState

TextBox CheckBoxCheckbox ListradiobuttonList

The status of the above control is handled by IPostBackeventHandler and the iPostBackDataHandler interface, not the mechanism of ViewState, so EnableViewState has no effect.

The ViewState object communicates with the page back, ASP usually uses the properties of the form and session to store data, and you can also use the ViewState object in ASP.NET to do the same processing. Store data in ViewState: ViewState [key] = value;

or

ViewState.Add (Key, Value);

Take out the data:

Tempstr = viewState [key]; return empty when it does not exist.

You cannot access the value of the control through the ViewState object.

Dynamically set up the control of the control: When you need to create a server control, a Radiobutton control is created as follows and add it to the form control collection:

Radiobutton RB = new radiobutton (); page.controls [1] .controls.add (pc);

The above code adds a control to the end of the control collection, and can also insert anywhere in the existing control.

Radiobutton RB = New Radiobutton (); page.controls [1] .controls.addat (1, pc); usually, these dynamic generated controls also need to generate into ViewState, but this feature is not fully implemented, especially Is the generated control inserted into the existing control. The result of ViewState is unpredictable when dynamically generating controls and existing controls. At the time of the page, the first non-dynamic generated control is generated in the ASPX page and reads ViewState in the Page_init and Page_Load events. When the control of the page reads ViewState, those dynamically generated controls have not been generated, so when the dynamically generated control is generated, the page will omit the viewState or fill the control with the remaining ViewState.

So, when you need to insert a dynamically generated control to the existing control, it is best to prohibit this control via EnableViewState. Reminder: 1. When there is a page back pass, you don't need to maintain the control, you will prohibit the viewState. 2. VIEWSTATE index is sensitive. 3. ViewState is not a cross page. 4. In order to be able to include viewState, the object must be fluidized or defined TypeConverter. 5. When the TEXTBOX's TextMode property is set to Password, its status will not be saved in ViewState, which should be considered for security. 6. Do not use ViewState when there is no return or redirect or redirect or transfer to (TRANSFER) other pages. 7. Be careful when building a control is dynamically established. 8. When a program is prohibited, the ViewState of all pages of this program is also banned. 9. ViewState is only continuous only when the page is back in itself.