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ViewState is a very important for the programmers in
page performance point of view. Programmers leave it enable for all the
controls even if there is no need to persist their value. Right use of
ViewState can increase the performance of the page drastically.
Using EnableViewState
property we only have 2 options.
- We can turn off view state altogether.
- Enable viewstate for the entire page and then turn it off on a control-by-control basis.
If you want to turn of ViewState for
the entire page and only enable it for specific controls on the page, then we have
to use ViewStateMode property in conjunction with EnableViewState.
EnableViewState property only accepts true or false values and the default value is true, where as ViewStateMode property can have a value of - Enabled, Disabled and inherit. Inherit is the default value for ViewStateMode property, If we set this then it takes the value from the parent and set it accordingly. Suppose If it has been set to Disabled at Page level and for a checkbox you set ViewStateMode = “Inherit” then it will disable the ViewState for the checkbox.
EnableViewState property only accepts true or false values and the default value is true, where as ViewStateMode property can have a value of - Enabled, Disabled and inherit. Inherit is the default value for ViewStateMode property, If we set this then it takes the value from the parent and set it accordingly. Suppose If it has been set to Disabled at Page level and for a checkbox you set ViewStateMode = “Inherit” then it will disable the ViewState for the checkbox.
ViewStateMode property is introduced
in 4.0, where as EnableViewState exists from a long time.
If
EnableViewState is to True, only then the ViewStateMode settings are applied,
where as, if EnableViewState is set to False then the control will not save its
view state, regardless of the ViewStateMode setting. In short if
EnableViewState is set to False, ViewStateMode setting is not respected.
To
disable view state for a page and to enable it for a specific control on the
page, set the EnableViewState property of the page and the control to true, set
the ViewStateMode property of the page to Disabled, and set the ViewStateMode property of the control to
Enabled.
