In C# List is a concrete implementation of the IList interface. The List is an implementation of the IList Interface. The idea is to program against the interface, not the implementation. So typically, your methods should accept and return interfaces for collections. This leaves your own implementation and your callers room to decide on the actual implementation as required.

Benefit of using an Interface is that you get to implement your functionality or better yet, the only functionality you require. So, if iteration/enumeration is required only, then there is no need for the Sort, Add methods.

[List][1] implements [IList interface][2]

IList is a interface and doesn&#39;t have any implementation, so the performance of IList depending the class it implements


  [1]: http://msdn.microsoft.com/en-us/library/6sh2ey19.aspx
  [2]: http://msdn.microsoft.com/en-us/library/system.collections.ilist.aspx

IList is the interface - see this question for more information - https://stackoverflow.com/questions/400135/c-listt-or-ilistt

So i&#39;ve read all the lines from a file thusly

    while (getline(ifile,line))
        {
            // logic
        }

Where ifile is an ifstream and line is a string

My problem is I now want to use getline over again, and seem to be unable to return to the beginning of the file, as running

    cout &lt;&lt; getline(ifile,line);

Will return 0

I&#39;ve attempted to use:

    ifile.seekg (0, ios::beg);

To no avail, it seems to have no effect. How do I go back to the start of the file?

Returning to beginning of file after getline

Can anyone tell me how to zipalign my .apk file with using eclipse. I have made my .apk file by giving command like,

 1. Right Click on Project Folder

 2. Click on &quot;Android Tools&quot; option from menu.

 3. Click on &quot;Export Signed Application Package...&quot; and my .apk generated in given application alias.


Now want to do zipalign for this above generated .apk file. Does any tool require to do so OR anything that can solve my problem.


How to zipalign the .apk file using eclipse?

&gt; **Possible Duplicates:**  
&gt; [IList&amp;lt;int&amp;gt; vs List&amp;lt;int&amp;gt;](https://stackoverflow.com/questions/1367539/ilistint-vs-listint)  
&gt; [C# - List&amp;lt;T&amp;gt; or IList&amp;lt;T&amp;gt;](https://stackoverflow.com/questions/400135/c-listt-or-ilistt)  

&lt;!-- End of automatically inserted text --&gt;

What is the difference between List and IList, which one has better performance and when to use List over IList and vice versa?

Difference between List and IList

> Possible Duplicates: 
> <a href="https://stackoverflow.com/questions/1367539/ilistint-vs-listint" target="_blank" rel="noopener noreferrer">IList&#x3C;int> vs List&#x3C;int></a> 
> <a href="https://stackoverflow.com/questions/400135/c-listt-or-ilistt" target="_blank" rel="noopener noreferrer">C# - List&#x3C;T> or IList&#x3C;T></a>

What is the difference between List and IList, which one has better performance and when to use List over IList and vice versa?

There is an entity type called `Product` that is generated by entity framework.
I have written this query

    public IQueryable&lt;Product&gt; GetProducts(int categoryID)
    {
        return from p in db.Products
               where p.CategoryID== categoryID
               select new Product { Name = p.Name};
    }

The code below throws the following error : 

&gt; &quot;The entity or complex type Shop.Product cannot be constructed in a
&gt; LINQ to Entities query&quot;

    var products = productRepository.GetProducts(1).Tolist();

But when I use `select p` instead of `select new Product { Name = p.Name};` it works correctly.

How can I preform a custom select section?


The entity cannot be constructed in a LINQ to Entities query

I&#39;ve been wondering about this issue for a while now.  

Of course there are things in C# that aren&#39;t optimized for speed, so using those objects or language tweaks (like LinQ) may cause the code to be slower. 

But if you don&#39;t use any of those tweaks, but just compare the same pieces of code in C# and C++ (It&#39;s easy to translate one to another). Will it really be that much slower ?

I&#39;ve seen comparisons that show that C# might be even faster in some cases, because in theory the JIT compiler should optimize the code in real time and get better results:  

[Managed Or Unmanaged?][1]

We should remember that the JIT compiler compiles the code at real time, but that&#39;s a 1-time overhead, the same code (once reached and compiled) doesn&#39;t need to be compiled again at run time.

The GC doesn&#39;t add a lot of overhead either, unless you create and destroy thousands of objects (like using String instead of StringBuilder). And doing that in C++ would also be costly.

Another point that I want to bring up is the better communication between DLLs introduced in .Net. The .Net platform communicates much better than Managed COM based DLLs. 

I don&#39;t see any inherent reason why the language should be slower, and I don&#39;t really think that C# is slower than C++ (both from experience and lack of a good explanation)..

So, will a piece of the same code written in C# will be slower than the same code in C++ ?  
In if so, then WHY ?

Some other reference (Which talk about that a bit, but with no explanation about WHY):

[Why would you want to use C# if its slower than C++?][2]


  [1]: http://www.grimes.nildram.co.uk/dotnet/man_unman.htm
  [2]: https://stackoverflow.com/questions/787375/why-would-you-want-to-use-c-if-its-slower-than-c

Is C# really slower than say C++?

This seems like a silly question, but I haven&#39;t found the answer, so here it is.  :)

In both cases, you will get an &quot;out-of-range&quot; exception if you fail to check the bounds of your collection.  Is this just coding style preference?

And in case someone needs an example:

    List&lt;byte&gt; myList = new List&lt;byte&gt;(){0x01, 0x02, 0x03};
    byte testByte = myList.ElementAt(2);
    
versus

    byte testByte = myList[2];





Why would I use Enumerable.ElementAt() versus the [] operator?

I have the following:

    string test = &quot;9586-202-10072&quot;

How would I get all characters to the right of the final `-` so 10072. The number of characters is always different to the right of the last dash.

How can this be done?

get all characters to right of last dash

I am writing a program to attach a file to email. Currently I am saving file using `FileStream` into disk, and then I use 

    System.Net.Mail.MailMessage.Attachments.Add(
        new System.Net.Mail.Attachment(&quot;file name&quot;)); 

I do not want to store file in disk, I want to store file in memory and from memory stream pass this to `Attachment`.

Attach a file from MemoryStream to a MailMessage in C#

What is a good practice of setting control focus in MVVM architecture. 

The way I envision it, is with a property on the ViewModel that would trigger a focus change when needed. And than have the UI controls bind/listen to that property so that if it changes, appropriate focus will be set. 

I see it as a ViewModel thing, because i want to set focus appropriate after a certain action was performed by the ViewModel, such as loading certain data. 

What&#39;s the best practice? 


WPF-MVVM: Setting UI control focus from ViewModel

I&#39;m trying to read an embedded text file with `System.Reflection.Assembly.GetExecutingAssembly().GetManifestResourceStream(resource);` but it gives me a `Stream`. The embedded resource is a text file so, how can I turn this `Stream` into a `TextReader`?

Get a TextReader from a Stream?

I have the situation where I&#39;m initializing my model in DatabaseInitializer() for EF 4.1 and get this annoying error `&quot;Validation failed for one or more entities. See &#39;EntityValidationErrors&#39; property for more details.&quot;` So, I go to this EntityValidationErrors and there is a field `{System.Data.Entity.Validation.DbEntityValidationResult}` which gives me no information at all about what field it was unable to initialize. 
Is there a way to get more info about this error?

**To clear things out:**

I know how to fix the string length problem. What I&#39;m asking is how do I get the exact field name that is breaking the model. 

Getting exact error type in from DbValidationException

I have **date and time** in a string formatted like that one:

    &quot;2011-03-21 13:26&quot; //year-month-day hour:minute

How can I parse it to `System.DateTime`?

I want to use functions like `DateTime.Parse()` or `DateTime.ParseExact()` if possible, to be able to specify the format of the date manually.



Parse string to DateTime in C#

I am wondering if there is any way to declare a byte variable in a short way like floats or doubles? I mean like `5f` and `5d`. Sure I could write `byte x = 5`, but that&#39;s a bit inconsequential if you use `var` for local variables.

Content Type	Original Author	Original Content on Stackoverflow
Question	Maxymus	View Question on Stackoverflow
Solution 1 - C#	Hassan Gulzar	View Answer on Stackoverflow
Solution 2 - C#	Arsen Mkrtchyan	View Answer on Stackoverflow
Solution 3 - C#	Stuart	View Answer on Stackoverflow

Difference between List and IList

C# Problem Overview

C# Solutions

Solution 1 - C#

Solution 2 - C#

Solution 3 - C#

How to zipalign the .apk file using eclipse?

Returning to beginning of file after getline

Attributions