Convert IQueryable type object to List T type

Question

I have IQueryable lt  gt  object   I want to Convert it into List lt  gt  with selected columns like new   ID   s ID  Name   s Name     Edited  Marc you are absolutely right   but I have only access to FindByAll   Method  because of my architecture    And it gives me whole object in IQueryable lt  gt   And I have strict requirement  for creating json object for select tag  to have only list lt  gt  type with two fields

User · Accepted Answer

Then just Select    var list   source Select s  gt new   ID   s ID  Name   s Name    ToList       edit  Actually - the names could be inferred in this case  so you could use   var list   source Select s  gt new   s ID  s Name    ToList      which saves a few electrons

User · Answer

The List class s constructor can convert an IQueryable for you   public static List lt TResult gt  ToList lt TResult gt  this IQueryable source        return new List lt TResult gt  source       or you can just convert it without the extension method  of course   var list   new List lt T gt  queryable

User · Answer

Here s a couple of extension methods I ve jury-rigged together to convert IQueryables and IEnumerables from one type to another  i e  DTO   It s mainly used to convert from a larger type  i e  the type of the row in the database that has unneeded fields  to a smaller one   The positive sides of this approach are    it requires almost no code to use - a simple call to  Transform lt DtoType gt    is all you need it works just like  Select s  new       i e  when used with IQueryable it produces the optimal SQL code  excluding Type1 fields that DtoType doesn t have    LinqHelper cs   public static IQueryable lt TResult gt  Transform lt TResult gt  this IQueryable source        var resultType   typeof TResult       var resultProperties   resultType GetProperties   Where p   gt  p CanWrite        ParameterExpression s   Expression Parameter source ElementType   s         var memberBindings           resultProperties Select p   gt              Expression Bind typeof TResult  GetMember p Name  0   Expression Property s  p Name    OfType lt MemberBinding gt          Expression memberInit   Expression MemberInit          Expression New typeof TResult            memberBindings                 var memberInitLambda   Expression Lambda memberInit  s        var typeArgs   new                         source ElementType               memberInit Type                 var mc   Expression Call typeof Queryable    Select   typeArgs  source Expression  memberInitLambda        var query   source Provider CreateQuery lt TResult gt  mc        return query     public static IEnumerable lt TResult gt  Transform lt TResult gt  this IEnumerable source        return source AsQueryable   Transform lt TResult gt

User · Answer

System Linq has ToList   on IQueryable lt   and IEnumerable lt     It will cause a full pass through the data to put it into a list  though   You loose your deferred invoke when you do this   Not a big deal if it is the consumer of the data

User · Answer

Add the following   using System Linq      and call ToList   on the IQueryable lt  gt

[c#] Convert IQueryable<> type object to List<T> type?

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