How to get distinct values in my dropdown list MVC

Question

I just stuck up with the issue, i am fetching data from database using entity framework, but facing problems.

Problem

My Role table has multiple Roles, it contains duplicate values like others 4 times, i am fetching it and binding it to dropdown, but i am getting others value 4 times in dropdown list

Here is the code that i am trying.

public List<RefrenceDataModel> GetJobRoles()
{
    List<RefrenceDataModel> lstRefrenceDataReturn = new List<RefrenceDataModel>();
    DataContext context = new DataContext();
    lstRefrenceDataReturn = context.JobsRoles.ToList().distinct().Select(items => new RefrenceDataModel() { RefrenceDataName = items.RoleName, RefrenceDataID = items.RoleID }).ToList<RefrenceDataModel>();
    return lstRefrenceDataReturn;
}

This code is returning duplicate values, but i don't want duplicates, what i am doing wrong?

I expect it's not working because your RefrenceDataModel type does not implement IEquatable<RefrenceDataModel> properly or at all. (And as a side note, is RefrenceDataModel spelt right? ;)) — Matthew Watson
– Matthew Watson, Commented May 29, 2013 at 7:22

Damith · Accepted Answer · 2013-05-29 07:25:54Z

1

by using GroupBy

lstRefrenceDataReturn = context.JobsRoles
  .GroupBy(r => r.RoleName)
  .Select(g => g.FirstOrDefault())
  .Select(items => new RefrenceDataModel() { RefrenceDataName = items.RoleName, RefrenceDataID = items.RoleID }).ToList<RefrenceDataModel>();

edited May 29, 2013 at 7:25

answered May 29, 2013 at 7:12

Damith

63.2k13 gold badges106 silver badges154 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Dhaval Marthak Over a year ago

Tried .Select(g => g.FirstOrDefault()) instead .Select(g => g.First()) and it worked... Thanks Damith

Damith Over a year ago

@DhavalMarthak That's better.

Collectives™ on Stack Overflow

How to get distinct values in my dropdown list MVC

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related