distinct values using LINQ

Question

I try to get distinct values in LINQ i try this for this first i create method and then i call this method on page load and assign

regiondrop.DataSource = getregion();
regiondrop.DataSourc=DataTextField="Region"
regiondrop.DataSourc==DataTextField="RID"


 private List<tab1> getregion()
        {
            using (T1 tee = new T1())
            {
            var tempList = tee.tbl1.ToList();
            var list = (from ta in tempList
            select new { ta.Region, ta.RID }).Select(x => new tbl1
            {
             Id = x.RID,
             reg=x.Region
             }).ToList();
            return list;
            }

        }

Data in db like this

RID Region
1   Canada
2   UK
3  London
4  Paris
5  UK
6  Brazil
7  London

Data in drop-down like this

Canada
UK
London
Paris
UK
Brazil
London

but i want data like this

Canada
UK
London
Paris
Brazil

any solution?

You could use `List.Distinct()` with a custom comparator on `Region` property. ([link](https://msdn.microsoft.com/en-us/library/bb920306%28v=vs.90%29.aspx)) — user5226582, Jun 22 '16 at 06:47

wake-0 · Accepted Answer · 2016-06-22T07:28:51.617

2

You can add a GroupBy

var list =  from ta in tempList
            group ta by ta.Region into g
            select g.FirstOrDefault();

edited Jun 22 '16 at 07:28

answered Jun 22 '16 at 06:44

wake-0

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and will i omit this or not?select new { ta.Region, ta.RID }).Select(x => new tbl1 { Id = x.RID, reg=x.Region }).ToList() – SUPER_USER Jun 22 '16 at 06:47
hi.. when i try like this .. private List getregion() { using (TrackDataEntities1 tee = new TrackDataEntities1()) { var tempList = tee.tblRegion_Uni.ToList(); var list = (from ta in tempList group ta by ta.Region into g select new { g.Key }); return list; } } – SUPER_USER Jun 22 '16 at 06:55
this shows same output. repeated values in dropdown – SUPER_USER Jun 22 '16 at 06:55
Are you binding on the correct list? debug the list. – wake-0 Jun 22 '16 at 06:58
yes when i set breakpoint then there is data in list – SUPER_USER Jun 22 '16 at 07:10
tempList and list data is same when i check like 7 records in tempList and 7 records in list – SUPER_USER Jun 22 '16 at 07:11
@SUPER_USER i have changed the code, have you tried it? – wake-0 Jun 22 '16 at 07:29
1

yes this work thank – SUPER_USER Jun 22 '16 at 07:34

distinct values using LINQ

1 Answers1