Question

I have written a LINQ query clause,But a error raise up.Can anyone help me out.Thanks in advance:

list = (from cr in dt.AsEnumerable()
select new Cards
{
   MemberNumber = cr.Field<string>("MemberNumber"),
   if( cr.Field<int>("CardState")==0)
   {
          CardState ="aaa";
   }
   if( cr.Field<int>("CardState")==1)
   {
     CardState ="bbb";
   }
   if( cr.Field<int>("CardState")==2)
   {
      CardState ="ccc";
   }
  if( cr.Field<int>("CardState")==3)
  {
     CardState ="ddd";
  }
  if( cr.Field<int>("CardState")==4)
  {
    CardState ="eee";
   }
  }).ToList<Cards>();

Answer 1

You can’t have branching logic like that inside an initializer. You could write it as a series of ternary operators, however:

list = (from cr in dt.AsEnumerable()
select new Cards
{
   MemberNumber = cr.Field<string>("MemberNumber"),
   CardState = ( cr.Field<int>("CardState")==0) ? "aaa" : 
               ( cr.Field<int>("CardState")==1) ? "bbb" :
               ( cr.Field<int>("CardState")==2) ? "ccc" :
               ( cr.Field<int>("CardState")==3) ? "ddd" :
               ( cr.Field<int>("CardState")==4) ? "eee" :
               ( cr.Field<int>("CardState")==5) ? "bbb" : null
}).ToList<Cards>();

Although a better solution may be to separate out that code block into a separate function and call it from your initializer:

list = (from cr in dt.AsEnumerable()
select new Cards
{
   MemberNumber = cr.Field<string>("MemberNumber"),
   CardState = GetCardState( cr.Field<int>("CardState"))
  }).ToList<Cards>();