c# - Dynamically Sort by lambda expression -

i m doing sorting in application shown below .

public iqueryable<users> selectall(string ssortexpression, string ssortorder) {     if (ssortorder == "asc")     {         switch (ssortexpression)         {             case "firstname":                 return usersrepository.entities.orderby(x => x.firstname);             case "lastname":                 return usersrepository.entities.orderby(x => x.lastname);             default:                 return usersrepository.entities.orderby(x => x.id);         }     }     else     {         switch (ssortexpression)         {             case "firstname":                 return usersrepository.entities.orderbydescending(x => x.firstname);             case "lastname":                 return usersrepository.entities.orderbydescending(x => x.lastname);             default:                 return usersrepository.entities.orderbydescending(x => x.username);         }     } } 

its fine , have sort on fields in users table (around 30 fields ) . method big

i tried using reflections this

public iqueryable<users> selectall(string ssortexpression, string ssortorder) {     var _property = usersrepository.gettype().getproperties().where(a => a.name == ssortexpression);     if (ssortorder == "asc")     {         return usersrepository.entities.orderby(x => _property);     }     else     {         return usersrepository.entities.orderbydescending(x => _property);     } } 

but faild.

is there better way ? in advance

the easiest way go: change method accept expression instead of string:

public iqueryable<users> selectall<tprop>(expression<func<users, tprop>> selector, string ssortorder) {     if (ssortorder == "asc")     {         return usersrepository.entities.orderby(selector);     }     else     {         return usersrepository.entities.orderbydescending(selector);     } } 

you can call as:

selectall(x => x.lastname, "asc"); 

or if need string, have generate expression tree using system.linq.expressions.expression class method:

public iqueryable<users> selectall<tprop>(string ssortexpression, string ssortorder) {     var param = expression.parameter(typeof(users));     var propexpression = expression.lambda<func<users, tprop>>(expression.property(param, ssortexpression), param);      if (ssortorder == "asc")     {         return usersrepository.entities.orderby(propexpression);     }     else     {         return usersrepository.entities.orderbydescending(propexpression);     } } 

but require specify generic type parameter on selectall call:

var results = selectall<int>("id", "asc");