c# - How to change orderby on postback for LINQ to SQL query -

i have drop down list set auto post needs return list of products in specified order. thought put query in own method , use parameter specify orderby, cannot work.

here example:

protected void show_products(int item)     {         using (storedatacontext db = new storedatacontext())         {            string query = "";             switch (item)             {                 case 1:                     query ="x.name";                     break;                 case 2:                     query = "x.msrp";                     break;                 default:                     break;             }             var q = db.items.orderby(x=> query).select(x => x);             foreach(var n in q)              {                work              }            }        } 

and drop down list method gets called on postback:

protected void ddlsortby_selectedindexchanged(object sender, eventargs e)     {         int value =int.parse(ddlsortby.selectedvalue);         show_products(value);     } 

var q = p in db.items         select q;  switch(item) {     case 1:         q.orderby(x=> x.name);         break;     case 2:         q.orderby(x=> x.msrp);         break;     default:         break;  }  foreach(var n in q) {     // work }