jQuery Grid Plugin - jqGrid

I am trying to add the navgrid single search option to jqgrid, and I am able to see when the find button is clicked in the search window that the _sesarch becomes true, but to search my grid content based on the column and the string (in this case the column is string/text)  I need to access the searchField, and the searchString on my controller, I am working with MVC 2 IN VS 2008 .

I am not adding any specific code in my html to carry those values my assumption is same as page number and row size for paging they should be accessable and the grid sorts and does paging ok ... can anyone see what could be the problem?