LinQ to SQL with Multi table

Question

Hi everyone! This is the first time i work with C# and LinQ to SQL

I have 2 table : "User" and "Wallet"

And i want use a query to take both table infomation, like this:

public static IList<Wallet1> GetMulti()
        {            
            using (var context = new WalletDataContext(ConnectionString))
            {
                var Wallets = (from Us in context.Users
                               join Wl in context.Wallets
                               on Us.IdUsers equals Wl.IdUsers                               
                               select Us).ToList();
            };
	}

Problem is: "not all code paths Return a value"

How can i fix it?

Some people used  "IList" or "IQuerryable". But i don't know how to do with them in milti table query.

           

Thanks so much :).

Answer 1

Friend,
  Remove the var Wallets statement with a return statement. NOw you are not returning anything from the method.
Else you can retunr the Wallets property after the assignment as in the methord.

public static IList<Wallet1> GetMulti()
        {            
            using (var context = new WalletDataContext(ConnectionString))
            {
                var Wallets = (from Us in context.Users
                               join Wl in context.Wallets
                               on Us.IdUsers equals Wl.IdUsers                               
                               select Us).ToList();
		return Wallets;
            };
	}

---

-- Thanks Ajith R Nair

Answer 2

Friend,
  You may code as below as well.

public static IList<Wallet1> GetMulti()
        {            
            using (var context = new WalletDataContext(ConnectionString))
            {
                return (from Us in context.Users
                               join Wl in context.Wallets
                               on Us.IdUsers equals Wl.IdUsers                               
                               select Us).ToList();
            };
	}

---

---

-- Thanks Ajith R Nair

Answer 3

Friend,
  You may code as below as well.

public static IList<Wallet1> GetMulti()
        {            
            using (var context = new WalletDataContext(ConnectionString))
            {
                return (from Us in context.Users
                               join Wl in context.Wallets
                               on Us.IdUsers equals Wl.IdUsers                               
                               select Us).ToList();
            };
	}

---

---

-- Thanks Ajith R Nair

Thanks about Return statement. 

But i want infomation of both table ? below this code just show me the Wallet table

public static IList<Wallet1> GetMulti()
        {            
            using (var context = new WalletDataContext(ConnectionString))
            {
                return  (from Us in context.Users
                                join Wl in context.Wallets
                                on Us.IdUsers equals Wl.IdUsers
                                //where Wl.IdUser = Convert.ToUInt16(1)
                                select Wl).ToList();             
            };           
            
        }

i was try 

select new {Wl.WDescription, Us.UName }).ToList();

But it didn't work. this code is follow : "IList". and i don't know how to change it ?

public static IList<Wallet1> GetMulti()

Thanks for helping

Answer 4

Friend,
  I am not sure about the return type, that is the type of the Wallet1 one class.

If you have a type defined as Wallet1, modify the code as below.

public static IList<Wallet1> GetMulti()
        {            
            using (var context = new WalletDataContext(ConnectionString))
            {
                return  (from Us in context.Users
                                join Wl in context.Wallets
                                on Us.IdUsers equals Wl.IdUsers
                                select new Wallet1(){FirstName=Us.FirstName, Address=WI.Address} ).ToList();             
            };             
        }

Here You need to fill with actual properties in Wallet class in the select statement. I have mentioned first name and lastname just for the reference.

---

-- Thanks Ajith R Nair

Answer 5

My Wallet1 is a class i was create:

class test
        {
            private String FirstName
            private String Address;
        }  

and a was user your code above.

public static IList<Wallet1> GetMulti()
        {            
            using (var context = new WalletDataContext(ConnectionString))
            {
                return  (from Us in context.Users
                                join Wl in context.Wallets
                                on Us.IdUsers equals Wl.IdUsers
                                select new Wallet1(){FirstName=Us.FirstName, Address=WI.Address} ).ToList();             
            };             
        }

but it have problem :

'TestSQL1.TestHelper.Wallet1.FristName' is inaccessible due to its protection level E:\Code\WP7\Test\TestSQL1\TestSQL1\TestHelper.cs

'TestSQL1.TestHelper.Wallet1.Address' is inaccessible due to its protection level E:\Code\WP7\Test\TestSQL1\TestSQL1\TestHelper.cs

Please help. thanks :)

Answer 6

Hi Dragon7188;

You need to make the two properties in the Wallet1 class public and should make the class public as well.

public class Wallet1
{
    public String FirstName
    public String Address;
}

public static IList<Wallet1> GetMulti()
{            
    using (var context = new WalletDataContext(ConnectionString))
    {
        return  (from Us in context.Users
                 join Wl in context.Wallets
                 on Us.IdUsers equals Wl.IdUsers
                 select new Wallet1()
                 {
                     FirstName = Us.FirstName, 
                     Address = WI.Address
                 } ).ToList();             
    };           
}

  

---

Fernando (MCSD)

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