asp.netgridviewviewstate
hi
i bind a DataTable to a gridview.
i want to use the DataTable in some postback event, and ii want to use viewstate.
does gridview save data in viewstate? if no what is the best way to do this.
(full story :
i have a custom gridview derived from standard asp.net gridview,
and i put a button in header to export data to excel, i want to use data saved in viewstate to export to excel)
thanks
As noted by Asem and Ron, adding the CausesValidation="false" attribute to the CommandField resolved the problem. The reason was that I had some other validation controls on the page and on the GridView update the page was firing the other validation controls, so I think its better to set a ValidationSummary property.
I suspect you're confusing saving ViewState, ie. serializing the ViewState collection in memory to a string representation or to an intermediate object that can be serialized easily, with actually modifying that ViewState in-memory object with its regular accessor methods.
What you may be hearing is that the SaveViewState() method is called after PreRender event. But that has little to do with when you get to modify the contents of the ViewState collection.
Checkout points 7. Prerender the Objects and 8. ViewState Saved in the article The ASP.NET Page Life Cycle. There's a good MSDN article that touches on this as well.
(source: microsoft.com)
Best Answer
The short answer is yes, information shown in the GridView, much like the current state of any control, is stored in ViewState. However, I do not think it is easy, if even possible, to get to this data yourself out of the ViewState collection that is available to WebControls. Instead, ASP.NET populates values from ViewState before running event handlers in the lifecycle, so if you interrogate your GridView object server-side in a handler, you should see the current values of the cells.