CODEWITHSUNDEEP
c#linq
AlexW
AlexW

Reputation: 2587

SingleOrDefault, how to write out default?

My below query

 var varUser = (from d in db.tblUsers where (d.ID == intID) select d).SingleOrDefault();
 return varUser.Forename + " " + varUser.Surname;

When using single or default how do I output a default value? so forename and surname is empty i want to wirte "No User" instead

Thanks

Upvotes: 1

Views: 430

Answers (4)

Abhitalks
Abhitalks

Reputation: 28427

Add a read-only property to your user class:

Public Class User
    Public Property FirstName As String
    Public Property LastName As String
    Public ReadOnly Property FullName() As String
        Get
            If String.IsNullOrEmpty(FirstName) AndAlso String.IsNullOrEmpty(LastName) Then
                Return "No Name"
            Else
                Return FirstName & " " & LastName
            End If
        End Get
    End Property
End Class

Now you can use your LINQ statement like this (DefaultIfEmpty clause):

Dim varUser = (From d In db.tblUsers Where (d.ID == intID) Select d).DefaultIfEmpty(New User).SingleOrDefault()

Return varUser.FullName

Sorry am not proficient in C# hence the VB code. But you get the idea.

Upvotes: 0

Lotok
Lotok

Reputation: 4607

return var varUser = db.tblUsers.SingleOrDefault(x=>x.id == intID) ?? "No User";

Upvotes: 1

Sergey Berezovskiy
Sergey Berezovskiy

Reputation: 236278

Check if user is null (default case) and return some default value (or throw exception)

if (varUser == null)
    return "No User"; // default value or exception

return String.Format("{0} {1}", varUser.Forename, varUser.Surname);

HINT: You can pass condition to SingleOrDefault method:

db.tblUsers.SingleOrDefault(u => u.ID == intID)

Or even use Find if you are using Entity Framework (internally it calls SingleOrDefault if entity cannot be found in entities tracked by context)

db.tblUsers.Find(intID)

Upvotes: 5

Amit
Amit

Reputation: 15387

try this

return varUser == null ? "No User" :
 string.Concat(varUser.Forename, " " , varUser.Surname);

Upvotes: 0

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