Typecast each object in an array on a single line of code, using LINQ

Question

Say I've got an array of User:

class User : IUserDowngraded
{
    public Int32 Id { get; set; }
}

... with downgraded functionality done by casting the objects to a specific interface:

interface IUserDowngraded
{
    Int32 Id { get; } // removes set functionality from property
}

... how would I cast those downgraded objects (IUserDowngraded) to User objects in a single line of code, using LINQ?

What I'm trying to avoid is this:

// pseudo-code alert:
IUserDowngraded[] downgradedUsers { IUserDowngraded, IUserDowngraded, ... };

var upgradedUsers = new User[downgradedUsers.Count()];

Int32 i = 0;

foreach (IUserDowngraded du in downgradedUsers)
{
    upgradedUsers[i] = (User)user;

    i++;
}

score 2 · Accepted Answer · answered May 06 '09 at 00:47

2

var upgradedUsers = downgradedUsers.Cast<User>();

Append a call to ToArray() if you want upgradedUsers as an array, of course.

answered May 06 '09 at 00:47

Noldorin

144,213
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Guess I kind'a missed that method. Thanks :) – cllpse May 06 '09 at 00:49
Yeah, LINQ has lots of goodies that are easy to miss... This is a particularly useful one. :) – Noldorin May 06 '09 at 00:51

score 0 · Answer 2 · answered May 06 '09 at 00:48

0

use the cast method....

SampleIntList = SampleStringList.Cast<int>().Select(x => Convert.ToInt32(x)).ToList();

answered May 06 '09 at 00:48

Muad'Dib

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score 0 · Answer 3 · edited May 23 '17 at 12:30

0

Also any of Implicit operators, Linq and Lambda expressions can make code less readable. But what is more readable? methods should work.

edited May 23 '17 at 12:30

Community

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1

answered May 06 '09 at 00:49

David McEwing

3,320
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Typecast each object in an array on a single line of code, using LINQ

3 Answers3