A [closure][1] in C# takes the form of an in-line delegate/[anonymous method][2]. A [closure][3] is attached to its parent method meaning that variables defined in parent&#39;s method body can be referenced from within the anonymous method. There is a great [Blog Post][4] here about it.

**Example:**

    public Person FindById(int id)
    {
        return this.Find(delegate(Person p)
        {
            return (p.Id == id);
        });
    }

You could also take a look at [Martin Fowler][5] or [Jon Skeet][6] blogs. I am sure you will be able to get a more &quot;In Depth&quot; breakdown from at least one of them....

**Example for C# 6:**

    public Person FindById(int id)
    {
        return this.Find(p =&gt; p.Id == id);
    }

which is equivalent to

    public Person FindById(int id) =&gt; this.Find(p =&gt; p.Id == id);

  [1]: http://en.wikipedia.org/wiki/Closure_(computer_science)
  [2]: http://msdn.microsoft.com/en-us/library/0yw3tz5k(VS.80).aspx
  [3]: http://en.wikipedia.org/wiki/Closure_(computer_science)
  [4]: https://web.archive.org/web/20150707082707/http://diditwith.net/PermaLink,guid,235646ae-3476-4893-899d-105e4d48c25b.aspx
  [5]: http://www.martinfowler.com/bliki/Closure.html
  [6]: http://csharpindepth.com/Articles/Chapter5/Closures.aspx

In this [article][1] the keyword extern can be followed by &quot;C&quot; or &quot;C++&quot;.  Why would you use &#39;extern &quot;C++&quot;&#39;?  Is it practical?


  [1]: http://msdn.microsoft.com/en-us/library/0603949d(VS.80).aspx

Why would you use &#39;extern &quot;C++&quot;&#39;?

I am lost in a big database and I am not able to find where the data I get comes from. I was wondering if it is possible with SQL Server 2005 to search for a string in all tables, rows and columns of a database?

Does anybody has an idea if it is possible and how?

Search for a string in all tables, rows and columns of a DB

### Duplicate
&gt;[Closures in .NET][1]

What are closures in C#?



[1]: https://stackoverflow.com/questions/428617/closures-in-net

What are &#39;closures&#39; in C#?

<h5 id="duplicate"><a aria-hidden="true" tabindex="-1" href="#duplicate"><span class="icon icon-link"></span></a>Duplicate</h5>
<p>><a href="https://stackoverflow.com/questions/428617/closures-in-net" target="_blank" rel="noopener noreferrer">Closures in .NET</a></p>
<p>What are closures in C#?</p>


What are the differences between multidimensional arrays `double[,]` and array-of-arrays `double[][]` in C#?

If there is a difference, what is the best use for each one?


What are the differences between a multidimensional array and an array of arrays in C#?

I have some elements in a ComboBox (WinForms with C#). I want their content to be static so that a user cannot change the values inside when the application is ran. I also do not want the user adding new values to the ComboBox

How to disable editing of elements in combobox for c#?

&gt; **Possible Duplicate:**  
&gt; [C#: Interfaces - Implicit and Explicit implementation](https://stackoverflow.com/questions/143405/c-interfaces-implicit-and-explicit-implementation)  

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

Would someone explain the differences between these two beasts and how to use them. AFAIK, many  pre.2.0 classes were implemented without generic types, thus causing latter version to implement both flavors of interfaces. Is the the only case why one would need to use them?


Can you also explain in depth how to use them.?


Thanks



implicit vs explicit interface implementation

I decided to put some effort in building a web browser from scratch. **What are the common functions, architectures, and features of modern web browsers** that I should know before getting started?

Any recommendations are highly appreciated!

How to get started building a web browser?

How can I get the HTML source for a given web address in C#?

How can I download HTML source in C#

I am very puzzled about this code:

    var closures = [];
    function create() {
      for (var i = 0; i &lt; 5; i++) {
        closures[i] = function() {
          alert(&quot;i = &quot; + i);
        };
      }
    }
    
    function run() {
      for (var i = 0; i &lt; 5; i++) {
        closures[i]();
      }
    }
    
    create();
    run();

From my understanding it should print `0,1,2,3,4` (isn&#39;t this the concept of closures?).

Instead it prints `5,5,5,5,5`.

I tried Rhino and Firefox.
Could someone explain this behavior to me?

Doesn&#39;t JavaScript support closures with local variables?



&lt;!-- begin snippet: js hide: false console: true babel: false --&gt;

&lt;!-- language: lang-js --&gt;

    var funcs = [];
    // let&#39;s create 3 functions
    for (var i = 0; i &lt; 3; i++) {
      // and store them in funcs
      funcs[i] = function() {
        // each should log its value.
        console.log(&quot;My value: &quot; + i);
      };
    }
    for (var j = 0; j &lt; 3; j++) {
      // and now let&#39;s run each one to see
      funcs[j]();
    }

&lt;!-- end snippet --&gt;

It outputs this:

&gt; My value: 3  
My value: 3  
My value: 3

Whereas I&#39;d like it to output:
&gt; My value: 0  
My value: 1  
My value: 2

---

The same problem occurs when the delay in running the function is caused by using event listeners:

&lt;!-- begin snippet: js hide: false console: true babel: false --&gt;

&lt;!-- language: lang-js --&gt;

    var buttons = document.getElementsByTagName(&quot;button&quot;);
    // let&#39;s create 3 functions
    for (var i = 0; i &lt; buttons.length; i++) {
      // as event listeners
      buttons[i].addEventListener(&quot;click&quot;, function() {
        // each should log its value.
        console.log(&quot;My value: &quot; + i);
      });
    }

&lt;!-- language: lang-html --&gt;

    &lt;button&gt;0&lt;/button&gt;
    &lt;br /&gt;
    &lt;button&gt;1&lt;/button&gt;
    &lt;br /&gt;
    &lt;button&gt;2&lt;/button&gt;

&lt;!-- end snippet --&gt;

… or asynchronous code, e.g. using Promises:

&lt;!-- begin snippet: js hide: false console: true babel: false --&gt;

&lt;!-- language: lang-js --&gt;

    // Some async wait function
    const wait = (ms) =&gt; new Promise((resolve, reject) =&gt; setTimeout(resolve, ms));

    for (var i = 0; i &lt; 3; i++) {
      // Log `i` as soon as each promise resolves.
      wait(i * 100).then(() =&gt; console.log(i));
    }

&lt;!-- end snippet --&gt;

It is also apparent in `for in` and `for of` loops:

&lt;!-- begin snippet: js hide: false console: true babel: false --&gt;

&lt;!-- language: lang-js --&gt;

    const arr = [1,2,3];
    const fns = [];

    for(var i in arr){
      fns.push(() =&gt; console.log(`index: ${i}`));
    }

    for(var v of arr){
      fns.push(() =&gt; console.log(`value: ${v}`));
    }

    for(var f of fns){
      f();
    }

&lt;!-- end snippet --&gt;

What’s the solution to this basic problem?

JavaScript closure inside loops – simple practical example

I&#39;m trying to figure out Python lambdas. Is `lambda` one of those &quot;interesting&quot; language items that in real life should be forgotten? 

I&#39;m sure there are some edge cases where it might be needed, but given the obscurity of it, the potential of it being redefined in future releases (my assumption based on the various definitions of it) and the reduced coding clarity - should it be avoided?  

This reminds me of overflowing (buffer overflow) of C types - pointing to the top variable and overloading to set the other field values.  It feels like sort of a techie showmanship but maintenance coder nightmare.


How are lambdas useful?

I saw the following in the source for [WebKit HTML 5 SQL Storage Notes Demo][1]:    

    function Note() {
      var self = this;

      var note = document.createElement(&#39;div&#39;);
      note.className = &#39;note&#39;;
      note.addEventListener(&#39;mousedown&#39;, function(e) { return self.onMouseDown(e) }, false);
      note.addEventListener(&#39;click&#39;, function() { return self.onNoteClick() }, false);
      this.note = note;
      // ...
    }

The author uses *self* in some places (the function body) and *this* in other places (the bodies of functions defined in the argument list of methods).  What&#39;s going on?  Now that I&#39;ve noticed it once, will I start seeing it everywhere?

  [1]: http://webkit.org/misc/DatabaseExample.html

What underlies this JavaScript idiom: var self = this?

I was just reading [this question][1] and wanted to try the alias method rather than the function-wrapper method, but I couldn&#39;t seem to get it to work in either Firefox 3 or 3.5beta4, or Google Chrome, both in their debug windows and in a test web page.

Firebug:

    &gt;&gt;&gt; window.myAlias = document.getElementById
    function()
    &gt;&gt;&gt; myAlias(&#39;item1&#39;)
    &gt;&gt;&gt; window.myAlias(&#39;item1&#39;)
    &gt;&gt;&gt; document.getElementById(&#39;item1&#39;)
    &lt;div id=&quot;item1&quot;&gt;

If I put it in a web page, the call to myAlias gives me this error:

    uncaught exception: [Exception... &quot;Illegal operation on WrappedNative prototype object&quot; nsresult: &quot;0x8057000c (NS_ERROR_XPC_BAD_OP_ON_WN_PROTO)&quot; location: &quot;JS frame :: file:///[...snip...]/test.html :: &lt;TOP_LEVEL&gt; :: line 7&quot; data: no]

Chrome (with &gt;&gt;&gt;&#39;s inserted for clarity):

    &gt;&gt;&gt; window.myAlias = document.getElementById
    function getElementById() { [native code] }
    &gt;&gt;&gt; window.myAlias(&#39;item1&#39;)
    TypeError: Illegal invocation
    &gt;&gt;&gt; document.getElementById(&#39;item1&#39;)
    &lt;div id=?&quot;item1&quot;&gt;?

And in the test page, I get the same &quot;Illegal invocation&quot;.

Am I doing something wrong?  Can anyone else reproduce this?

Also, oddly enough, I just tried and it works in IE8.

  [1]: https://stackoverflow.com/questions/954417/make-alias-to-document-getelementbyid-in-javascript

Content Type	Original Author	Original Content on Stackoverflow
Question	Shane Scott	View Question on Stackoverflow
Solution 1 - C#	cgreeno	View Answer on Stackoverflow

What are 'closures' in C#?

C# Problem Overview

Duplicate

C# Solutions

Solution 1 - C#

Search for a string in all tables, rows and columns of a DB

Why would you use 'extern "C++"'?

Attributions