When the MaxPageStateFieldLength property is set to a positive number, the view state sent to the client browser is broken into multiple hidden fields, and each field's value is less than the size specified in the MaxPageStateFieldLength property.
Setting the MaxPageStateFieldLength property to a negative number (the default) indicates that the view-state field should not be separated into chunks. Setting the MaxPageStateFieldLength to a small number may result in poor performance.
Set the value of the MaxPageStateFieldLength property in the pages element of the Web.config file.
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2