Sorry,
in the above example of declaration and calling View state
Key Name Should the same but it was not so while declaring 
the key name was "ViewStateVariableName" and while calling 
the key name was "ViewStateVariable" which won't work if 
so, it was by mistake,
 ie..,when called name was changed.., 
Cool:-)
 Below is the Correct Format:

**********************'
ViewState Declared As:'
**********************'
ViewState["ViewStateVariableName"] = 1;
**********************************'
Above ViewState Can be called As: '
**********************************'
int number = (int) ViewState["ViewStateVariableName"];

AFAIK