you can make it programitcally ,take the data in Datatable first set the Gridview Datasource = Datatable. & then call DataBind()
Then using on event of dropdown change (dont forget to on autopostback)...
or any button click event if want to use all three dropdown value...
you can reasign the datasource of Gridview.
By Using the same datatable to DataView & its Rowfilter property..
Or using different query... & dont forget to call at last DataBind()
This is the a simple senario of that.
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