You need to use the &lt;code&gt;[Obsolete]&lt;/code&gt; attribute.

Example:

    [Obsolete(&quot;Not used any more&quot;, true)]
	public class MyDeprecatedClass
	{
		//...
	}
	
The parameters are optional. The first parameter is for providing the reason it&#39;s obsolete, and the last one is to throw an error at compile time instead of a warning.



As per Doak&#39;s answer, but the attribute&#39;s second parameter should be set to false if you want the code to compile:

    [Obsolete(&quot;Not used any more&quot;, false)]
    public class MyDeprecatedClass
    {
            //...
    }

This will just throw warnings.

The reason to not erase a class and deprecate instead is to adhere to some &quot;politeness policies&quot; when your code is an estabished API and then is consumed by third parties. 

If you deprecate instead of erase, you give consumers a life cycle policy (e.g., maintenance and existence of the classes until version X.X) in order to allow them to plan a proper migration to your new API.

If you are using version control I would recommend just deleting the class.  There is no reason to have unused code around.

Version control will be a handy undo if you decide later that you want the class.

Lets say I have a concrete class Class1 and I am creating an anonymous class out of it.

    Object a = new Class1(){
            void someNewMethod(){
            }
          };

Now is there any way I could overload the constructor of this anonymous class. Like shown below

    Object a = new Class1(){
            void someNewMethod(){
            }
            public XXXXXXXX(int a){
              super();
              System.out.println(a);
            }
          };

With something at xxxxxxxx to name the constructor?

Accessing constructor of an anonymous class

Suppose I have a process which spawns exactly one child process. Now when the parent process exits for whatever reason (normally or abnormally, by kill, ^C, assert failure or anything else) I want the child process to die. How to do that correctly?


----------
Some similar question on stackoverflow:

 * (asked earlier) [https://stackoverflow.com/questions/269494/how-can-i-cause-a-child-process-to-exit-when-the-parent-does][1]
 * (asked later) [https://stackoverflow.com/questions/395877/are-child-processes-created-with-fork-automatically-killed-when-the-parent-is-k][2]


  [1]: https://stackoverflow.com/questions/269494/how-can-i-cause-a-child-process-to-exit-when-the-parent-does
  [2]: https://stackoverflow.com/questions/395877/are-child-processes-created-with-fork-automatically-killed-when-the-parent-is-k
----------
Some similar question on stackoverflow for **Windows**:  

 * https://stackoverflow.com/questions/53208/how-do-i-automatically-destroy-child-processes-in-windows  
 * https://stackoverflow.com/questions/3342941/kill-child-process-when-parent-process-is-killed

How to make child process die after parent exits?

&gt; **Possible Duplicate:**  
&gt; [How do I mark a method as Obsolete/Deprecated? - C#](https://stackoverflow.com/questions/1759352/how-do-i-mark-a-method-as-obsolete-deprecated-c-sharp)  

&lt;!-- End of automatically inserted text --&gt;

How do you mark a class as deprecated? I do not want to use a class any more in my project, but do not want to delete it before a period of 2 weeks.

How to mark a class as Deprecated?

> Possible Duplicate: 
> <a href="https://stackoverflow.com/questions/1759352/how-do-i-mark-a-method-as-obsolete-deprecated-c-sharp" target="_blank" rel="noopener noreferrer">How do I mark a method as Obsolete/Deprecated? - C#</a>

How do you mark a class as deprecated? I do not want to use a class any more in my project, but do not want to delete it before a period of 2 weeks.

I have a dll that was written in c++, I need to use this dll in my c# code. After searching I found that using P/Invoke would give me access to the function I need, but these functions are defined with in a class and use non-static private member variables. So I need to be able to create an instance of this class to properly use the functions. How can I gain access to this class so that I can create an instance? I have been unable to find a way to do this. 

I guess I should note that the c++ dll is not my code.

using a class defined in a c++ dll in c# code

At the moment I&#39;m creating a `DateTime` for each month and formatting it to only include the month.  
Is there another or any better way to do this?

How to list all month names, e.g. for a combo?

What is the correct syntax for this:

    IList&lt;string&gt; names = &quot;Tom,Scott,Bob&quot;.Split(&#39;,&#39;).ToList&lt;string&gt;().Reverse();


What am I messing up?
What does TSource mean?

C# Syntax - Split String into Array by Comma, Convert To Generic List, and Reverse Order

I have a table User which has an identity column `UserID`, now what is the correct Linq to Entity line of code that would return me the max `UserID`?

I&#39;ve tried:

    using (MyDBEntities db = new MyDBEntities())
    {
    	var User = db.Users.Last();
    	// or
    	var User = db.Users.Max();
    
    	return user.UserID;
    }

but `Last` and `Max` don&#39;t seem to be supported.

Any ideas?

How do I get the max ID with Linq to Entity?

I always tell in c# a variable of type double is not suitable for money. All weird things could happen. But I can&#39;t seem to create an example to demonstrate some of these issues. Can anyone provide such an example?

(edit; this post was originally tagged C#; some replies refer to specific details of `decimal`, which therefore means [`System.Decimal`][1]).

(edit 2: I was specific asking for some c# code, so I don&#39;t think this is language agnostic only)

  [1]: http://msdn.microsoft.com/en-us/library/system.decimal.aspx

Is a double really unsuitable for money?

Scott Gu just posted about a new set of charting controls being distributed by the .NET team. They look incredible: http://weblogs.asp.net/scottgu/archive/2008/11/24/new-asp-net-charting-control-lt-asp-chart-runat-quot-server-quot-gt.aspx

The million dollar question is ... will they work with MVC, and if so, when?

New asp.net charting controls - will they work with MVC (eventually)?

How do I make the computer&#39;s internal speaker beep in C# without external speakers?

How can I make the computer beep in C#?

I am trying to install a Windows service using InstallUtil.exe and am getting the error message

&gt;    System.BadImageFormatException: Could not load file or assembly &#39;`{xxx.exe}`&#39; or one of its dependencies. An attempt was made to load a program with an incorrect format.

What gives?


----

EDIT: (Not by OP) Full message extracted from dup getting way more hits [for googleability]:

&gt;    C:\Windows\Microsoft.NET\Framework64\v4.0.30319&gt;InstallUtil.exe C:\xxx.exe
    Microsoft (R) .NET Framework Installation utility Version 4.0.30319.1
    Copyright (c) Microsoft Corporation.  All rights reserved.
    
&gt;    Exception occurred while initializing the installation:
    System.BadImageFormatException: Could not load file or assembly &#39;file:///C:\xxx.exe&#39; or one of its dependencies. An attempt was made to load a program with an incorrect format..
    


System.BadImageFormatException: Could not load file or assembly (from installutil.exe)

I&#39;m trying to find out how much memory my objects take to see how many of them are ending up on the [Large Object Heap][1] (which is anything over 85,000 bytes).

Is it as simple as adding 4 for an int, 8 for a long, 4 (or 8 if you&#39;re on 64 bit) for any reference types etc for each object, or are there overheads for methods, properties, etc.?

  [1]: https://docs.microsoft.com/en-us/dotnet/standard/garbage-collection/large-object-heap





Find out the size of a .NET object

Since I started learning [F#][1] and [OCaml][2] last year, I&#39;ve read a huge number of articles which insist that design patterns (especially in Java) are workarounds for the missing features in imperative languages. One article I found [makes a fairly strong claim][3]:

&gt; Most people I&#39;ve met have read 
&gt; [the Design Patterns book][4] by the Gang of
&gt; Four (GoF). Any self respecting programmer
&gt; will tell you that the book is
&gt; language agnostic and the patterns
&gt; apply to software engineering in
&gt; general, regardless of which language
&gt; you use. This is a noble claim.
&gt; Unfortunately it is far removed from
&gt; the truth.
&gt;
&gt; Functional languages are extremely
&gt; expressive. **In a functional language
&gt; one does not need design patterns
&gt; because the language is likely so high
&gt; level, you end up programming in
&gt; concepts that eliminate design
&gt; patterns all together.**

The main features of functional programming (FP) include functions as first-class values, currying, immutable values, etc. It doesn&#39;t seem obvious to me that OO design patterns are approximating any of those features.

Additionally, in functional languages which support OOP (such as F# and OCaml), it seems obvious to me that programmers using these languages would use the same design patterns found available to every other OOP language. In fact, right now I use F# and OCaml every day, and there are no striking differences between the patterns I use in these languages vs. the patterns I use when I write in Java.

Is there any truth to the claim that functional programming eliminates the need for OOP design patterns? If so, could you post or link to an example of a typical OOP design pattern and its functional equivalent?


  [1]: http://en.wikipedia.org/wiki/F_Sharp_%28programming_language%29
  [2]: http://en.wikipedia.org/wiki/Objective_Caml
  [3]: http://www.defmacro.org/ramblings/fp.html
  [4]: http://en.wikipedia.org/wiki/Design_Patterns

Does functional programming replace GoF design patterns?

What are some ways to write object-oriented code in C? Especially with regard to polymorphism.

&lt;hr/&gt;

See also this Stack Overflow question *[Object-orientation in C][1]*.

  [1]: https://stackoverflow.com/questions/415452/object-orientation-in-c


How would one write object-oriented code in C?

If I have several classes with functions that I need but want to store separately for organisation, can I extend a class to have both?

i.e. `class a extends b extends c`

edit: I know how to extend classes one at a time, but I&#39;m looking for a method to instantly extend a class using multiple base classes - AFAIK you can&#39;t do this in PHP but there should be ways around it without resorting to `class c extends b`, `class b extends a`

Can I extend a class using more than 1 class in PHP?

How do I call the parent function from a derived class using C++? For example, I have a class called `parent`, and a class called `child` which is derived from parent. Within 
each class there is a `print` function.  In the definition of the child&#39;s print function I would like to make a call to the parents print function.  How would I go about doing this?




How to call a parent class function from derived class function?

I just joined a new C++ software project and I&#39;m trying to understand the design.  The project makes frequent use of unnamed namespaces.  For example, something like this may occur in a class definition file:

    // newusertype.cc
    namespace {
      const int SIZE_OF_ARRAY_X;
      const int SIZE_OF_ARRAY_Y;
      bool getState(userType*,otherUserType*);
    }
    
    newusertype::newusertype(...) {...

What are the design considerations that might cause one to use an unnamed namespace?  What are the advantages and disadvantages?

Why are unnamed namespaces used and what are their benefits?

My application I&#39;ve recently inherited is FULL of deprecation warnings about the constructor:

    Date d = new Date(int year, int month, int day)

Does anyone know or can point to a reason why something as simple as this was &quot;replaced&quot; with something like this:

    Date d = null;
    Calendar cal = GregorianCalendar.getInstance();
    cal.set(1900 + year, month, day);
    d = cal.getTime();

Now, obviously deprecation warnings are not a problem in themselves, but can you imagine the millions of LOC that would be crying out in agony if this constructor was ever removed?

In my brief little play at benchmarking, the latter takes about 50% more time to execute.

Why was &quot;new Date(int year, int month, int day)&quot; deprecated?

Is there an ability in VB.NET to deprecate code?
I know that in C# there are &#39;attributes&#39;, and tags in java; is there anything similar in VB.NET, other than leaving a `&#39;todo:`...?

In VB.NET, can I mark a function as deprecated?

I keep getting this :

    DeprecationWarning: integer argument expected, got float

How do I make this message go away? Is there a way to avoid warnings in Python?

How to ignore deprecation warnings in Python

I get a warning that BaseException.message is deprecated in Python 2.6 when I use the following user-defined exception:

    class MyException(Exception):
    
        def __init__(self, message):
            self.message = message
        
        def __str__(self):
            return repr(self.message)

This is the warning:

&lt;!-- language: lang-none --&gt;

    DeprecationWarning: BaseException.message has been deprecated as of Python 2.6
    self.message = message

What&#39;s wrong with this? What do I have to change to get rid of the deprecation warning?

BaseException.message deprecated in Python 2.6

Why is Java Vector considered a legacy class, obsolete or deprecated?

Isn&#39;t its use valid when working with concurrency?

And if I don&#39;t want to manually synchronize objects and just want to use a thread-safe collection without needing to make fresh copies of the underlying array (as `CopyOnWriteArrayList` does), then is it fine to use `Vector`?

What about `Stack`, which is a subclass of `Vector`, what should I use instead of it?

Content Type	Original Author	Original Content on Stackoverflow
Question	Mister Dev	View Question on Stackoverflow
Solution 1 - C#	Patrick Desjardins	View Answer on Stackoverflow
Solution 2 - C#	Rebecca	View Answer on Stackoverflow
Solution 3 - C#	Gabriel	View Answer on Stackoverflow
Solution 4 - C#	jjnguy	View Answer on Stackoverflow

How to mark a class as Deprecated?

C# Problem Overview

C# Solutions

Solution 1 - C#

Solution 2 - C#

Solution 3 - C#

Solution 4 - C#

How to make child process die after parent exits?

Accessing constructor of an anonymous class

Attributions