I need help about using LINQ ?

Question

hi . i have this code 

 public IQueryable<AllVehicleView> GetAllVehicles()
        {
            var dataContext = new HostDBEntities();
            var allVehicles = from s in dataContext.AllVehicles
                              select new AllVehicleView { ID = s.ID, VehicleName = s.VehicleName, BelongTo = s.BelongTo};
            return allVehicles;
        }  

this code return Table called AllVehicles and its contain  column called BelongTo . how can i use Distinct() . to return no duplicate values from BelongTo 

thank you so much my helpers 

---

Hesham Hemdan Saleh

Answer 1

Just to clarify it: You want to return only one car, even when it's owner has more than one?

Answer 2

i need to return all values as i mentioned except the the BelongTo , i want Belong to be not repeated values here is my table 

AllVehicles Table 

VehicleID , VehicleName , BelongTo

1                jackson           office1

2                michael           office1

3                riky                 office1

4               jacky               office2

5               piter                office2

i have a dropdown box and its bind only BelongTo column and i want just show me each office with unique name , like dont have to repeat office1 , 3 times because its with 3 rows in table

i hope you understand me thank you stefan

---

Hesham Hemdan Saleh

Answer 3

Hi,

If you only want to bind the BelongsTo, why include the ID and VehicleName in the returned IQueryable?

To get distinct BelongsTo values, use this:

allVehicles.Select(avv => avv.BelongsTo).Distinct();

Hope this helps

---

Please mark the best replies as answers
Blog: bloggingabout.net/blogs/rick
Twitter: @rickvdbosch

Answer 4

try this code 

var results = from s in datacontext.AllVehicles
              group s.ID by s.BelongTo into g
              select new { Id= g.Key, Cars = g.ToList() };

good luck 

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Please mark the post as an answer that helps/solves your problem.

Answer 5

Just return specific column value from the table using linq and bind it to the dropdownbox as said above

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Mark it as helpful if so! Thanks

Answer 6

You can do it like Rick wrote.

BUT: Your data context should provide this information by itself using the database to optimize this kind of query. Cause it is a bad practice to load that entire table for extracting a value which should by easier queried in the database backend as view.

Answer 7

Hi Hesham,

Are you using entity framework or LINQ to SQL ?

Regards,

---

Lisa Zhu [MSFT]
MSDN Community Support | Feedback to us
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Please remember to mark the replies as answers if they help and unmark them if they provide no help.

Answer 8

Hey , first i would like to thank all of you . and i will use most of your help codes and back to you later i just need to modify my code and see the result .

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Hesham Hemdan Saleh

Answer 9

Lise , am using Entity ,

---

Hesham Hemdan Saleh

Answer 10

ok Guys , lets make my example easier .

here is my code with only BelongTo

public IQueryable<AllVehicleView> GetAllVehicles()
        {
            var dataContext = new HostDBEntities();
            var allVehicles = from s in dataContext.AllVehicles
                           
                             select  new AllVehicleView { BelongTo = s.BelongTo };
            return allVehicles;
        }     

all i need is just return the BelongTo with no duplicate values

---

Hesham Hemdan Saleh

Answer 11

public IQueryable<AllVehicleView> GetAllVehicles()
        {
            var dataContext = new HostDBEntities();
            var allVehicles = (from s in dataContext.AllVehicles
	select new AllVehicleView { BelongTo = s.BelongTo }).distinct();
            return allVehicles;
        }  

Try that.

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JP Cowboy Coders Unite!

Answer 12

Lise , am using Entity ,

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Hesham Hemdan Saleh

Okay, so I will move this thread to the most related forum:ADO.NET Entity Framework and LINQ to Entities for better support.

Thanks for your understanding.

Regards,

---

Lisa Zhu [MSFT]
MSDN Community Support | Feedback to us
Develop and promote your apps in Windows Store
Please remember to mark the replies as answers if they help and unmark them if they provide no help.