asp.net session

Based on filter criteria(multiple drop downs,tes\xt boxes) fethcing the 5k+ records and binding to gridveiw.           Gridview have drop down filters on every column ,and also sorting  on every column( I am hitting the DB when first time clickedo on button) .
Fitering based on choosen value from dropdownlist.   I don't wan to pass page size,page index to back end due to business reasons.
button _click()
{
sessino("abc")=null
BindGrid(x,y,z,c);
}
 
BindGrid(x,v,z,a,b,c)
{
If( session is not nlll)
{
obg.dal..method(z,z,,z,,zv,v);
session("abc")=datatable:
 
}
}
dropdownlistfikter_selectindexchanged
{
We have already fetched data from Back end,so dont want to make call to back end.
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