Cannot implicitly convert type System.Collections.generic to

Question

namespace Automated_VotingSystem.Models
{
    public class DisplayCandidatesList
    {
        public List? DisplayCandidateslist { get; set;}
    }
}

namespace Automated_VotingSystem.Models
{
    public partial class DisplayCandidates
    {
        public int VoterId { get; set; }
        public int? CollegeId { get; set; }
        public int? EventId { get; set; }
        public int CandidateId { get; set; }
        public string? Manifesto { get; set; }
        public byte[]? Symbol { get; set; }
        public string? Symbol_path { get; set; }        
    }
}

public List DisplayCandidateslist { get; set; }

[HttpGet("[action]/{GetAllCandidates}")]
public async Task DisplayAllCandidates()
{
    var list_of_candidates = (from c in _context.CandidateTables
                              join ac in _context.ApprovedCandidateTables on c.CandidateId equals ac.CandidateId
                              join s in _context.SymbolTables on c.SymbolId equals s.SymbolId
                              where ac.Approval == true
                              select new
                              {
                                  candidate_id = ac.CandidateId,
                                  manifesto = c.Manifesto,
                                  symbol_path = s.Symbol_path
                              }).ToList();
    return  list_of_candidates;
}

The 1st snippet is my class, 2nd snippet is my model and 3rd snippet is my Controller. While executing the code I am getting a error after returning list of candidates as

Cannot implicitly convert type 'System.Collections.Generic.List<>' to 'Automated_VotingSystem.Models.DisplayCandidatesList'

user_4596822 · Answer

I am not sure what you trying to do here,But It seems ; You dont need "DisplayCandidatesList" class, you only need one "DisplayCandidates" class. If you use this class in another class as a form of list,use like that List instead of List? ,But here you dont need that I guess.

Your list method can return "Task" like that, I suggest you to study topic Collections and Generics in C# And dont use that naming in Controllers actions check naming standarts https://restfulapi.net/resource-naming/

user_11392290 · Answer

Your the DisplayAllCandidates method is expecting a list of DisplayCandidates. Therefore, use explicit type DisplayCandidates instead of anonymous and change the action return type to List< DisplayCandidate >>. And since it is an async action, it is better to use an async return

public async Task> DisplayAllCandidates()
{
    return await (from c in _context.CandidateTables
                              
                         ....
                              select new DisplayCandidates
                              {
                                  CandidateId = ac.CandidateId,
                                  Manifesto = c.Manifesto,
                                  Symbol_path = s.Symbol_path
                              }).ToListAsync();

Cannot implicitly convert type System.Collections.generic to <ProjectNamespace.List>

2 Answers