It&#39;s a [zero-width no-break space](http://www.fileformat.info/info/unicode/char/feff/index.htm).  
It&#39;s more commonly used as a [byte-order mark (BOM)](http://en.wikipedia.org/wiki/Byte_Order_Mark).

If you are using Notepad++, try converting to UTF-8 (no BOM), and also make sure ALL your files in the project are the same file system format. 

If you are reading from a file you have opened in notepad, it may have added it as it is one of several programs notorious for doing so. 

You can remove it with:

    Trim(new char[]{&#39;\uFEFF&#39;,&#39;\u200B&#39;});

I need to develop an app that has the share function. I have to share on Facebook, twitter, email and maybe other services. 

How can I do this? There a library on the net? For the iOS development there were ShareKit, but for Android?

Thanks :)

Android - Share on Facebook, Twitter, Mail, ecc

I want to return multiple values from a function written in groovy and receive them , but i am getting an error

&gt; class org.codehaus.groovy.ast.expr.ListExpression, with its value &#39;[a,
&gt; b]&#39;, is a bad expression as the left hand side of an assignment
&gt; operator

My code is 

    int a=10
    int b=0
    println &quot;a is ${a} , b is ${b}&quot;
    [a,b]=f1(a)
    println &quot;a is NOW ${a} , b is NOW ${b}&quot;

    def f1(int x) {   
      return [a*10,a*20]
    }


how to accept multiple parameters from returning function in groovy

I have two strings.

one is &quot;\&quot;&quot;

and the other is &quot;\&quot;&quot;

I think that they are same.

However, `String.Compare` says they are different.

This is very strange.

Here&#39;s my code:


    string b = &quot;\&quot;&quot;;
    string c = &quot;\&quot;&quot;;

    if (string.Compare(b, c) == 0)
    {
        Console.WriteLine(&quot;Good&quot;);
    }

    if (c.StartsWith(&quot;\&quot;&quot;))
    {
        Console.WriteLine(&quot;C&quot;);
    }

    if (b.StartsWith(&quot;\&quot;&quot;))
    {
        Console.WriteLine(&quot;B&quot;);
    }



I expected that it may print &quot;GoodCB&quot;.

However, it only prints &quot;B&quot;.

In my debugger, `c[0]` is 65279 &#39;&#39; and `c[1]` is 34 &#39;&quot;&#39;. and `b[0]` is &#39;&quot;&#39;. 

But I don&#39;t know what 65279 &#39;&#39; is. 

Is it an empty character? 


What is this char? 65279 &#39;&#39;

I have two strings.
one is """
and the other is """
I think that they are same.
However, <code>String.Compare</code> says they are different.
This is very strange.
Here's my code:
<pre><code class="hljs language-vbnet">string b = "\"";
string c = "\"";

if (string.Compare(b, c) == 0)
{
 Console.WriteLine("Good");
}

if (c.StartsWith("\""))
{
 Console.WriteLine("C");
}

if (b.StartsWith("\""))
{
 Console.WriteLine("B");
}
</code></pre>
I expected that it may print "GoodCB".
However, it only prints "B".
In my debugger, <code>c[0]</code> is 65279 '' and <code>c[1]</code> is 34 '"'. and <code>b[0]</code> is '"'.
But I don't know what 65279 '' is.
Is it an empty character?

I need to detect when Windows is shutdown (or restarted) or when the user is logging off. I need to properly close the application before the application is closed.
I noticed that no exit application event is raised when Windows is closing day.

I read the post https://stackoverflow.com/questions/4617538/is-there-a-way-in-c-to-detect-a-windows-shutdown-logoff-and-cancel-that-action

but I&#39;m not sure of where I should perform the operations before closing.
Thanks.

How to detect Windows shutdown or logoff

The Task Parallel Library is great and I&#39;ve used it a lot in the past months. However, there&#39;s something really bothering me: the fact that [`TaskScheduler.Current`][1] is the default task scheduler, not [`TaskScheduler.Default`][2]. This is absolutely not obvious at first glance in the documentation nor samples.

`Current` can lead to subtle bugs since its behavior is changing depending on whether you&#39;re inside another task. Which can&#39;t be determined easily.

Suppose I am writting a library of asynchronous methods, using the standard async pattern based on events to signal completion on the original synchronisation context, in the exact same way XxxAsync methods do in the .NET Framework (eg `DownloadFileAsync`). I decide to use the Task Parallel Library for implementation because it&#39;s really easy to implement this behavior with the following code:

    public class MyLibrary
    {
        public event EventHandler SomeOperationCompleted;

        private void OnSomeOperationCompleted()
        {
            SomeOperationCompleted?.Invoke(this, EventArgs.Empty);
        }

        public void DoSomeOperationAsync()
        {
            Task.Factory.StartNew(() =&gt;
            {
                Thread.Sleep(1000); // simulate a long operation
            }, CancellationToken.None, TaskCreationOptions.None, TaskScheduler.Default)
            .ContinueWith(t =&gt;
            {
                OnSomeOperationCompleted(); // trigger the event
            }, TaskScheduler.FromCurrentSynchronizationContext());
        }
    }

So far, everything works well. Now, let&#39;s make a call to this library on a button click in a WPF or WinForms application:

    private void Button_OnClick(object sender, EventArgs args)
    {
    	var myLibrary = new MyLibrary();
    	myLibrary.SomeOperationCompleted += (s, e) =&gt; DoSomethingElse();
    	myLibrary.DoSomeOperationAsync(); // call that triggers the event asynchronously
    }

    private void DoSomethingElse() // the event handler
    {
        //...
    	Task.Factory.StartNew(() =&gt; Thread.Sleep(5000)); // simulate a long operation
        //...
    }

Here, the person writing the library call chose to start a new `Task` when the operation completes. Nothing unusual. He or she follows examples found everywhere on the web and simply use `Task.Factory.StartNew` without specifying the `TaskScheduler` (and there is no easy overload to specify it at the second parameter). The `DoSomethingElse` method works fine when called alone, but as soon at it&#39;s invoked by the event, the UI freezes since `TaskFactory.Current` will reuse the synchronization context task scheduler from my library continuation.

Finding out this could take some time, especially if the second task call is buried down in some complex call stack. Of course, the fix here is simple once you know how everything works: always specify `TaskScheduler.Default` for any operation you&#39;re expecting to be running on the thread pool. However, maybe the second task is started by another external library, not knowing about this behavior and naively using `StartNew` without a specific scheduler. I&#39;m expecting this case to be quite common.

After wrapping my head around it, I can&#39;t understand the choice of the team writing the TPL to use `TaskScheduler.Current` instead of `TaskScheduler.Default` as the default:

 - It&#39;s not obvious at all, `Default` is not the default! And the documentation is seriously lacking.
 - The real task scheduler used by `Current` depends of the call stack! It&#39;s hard to maintain invariants with this behavior.
 - It&#39;s cumbersome to specify the task scheduler with `StartNew` since you have to specify the task creation options and cancellation token first, leading to long, less readable lines. This can be alleviated by writing an extension method or creating a `TaskFactory` that uses `Default`.
 - Capturing the call stack has additional performance costs.
 - When I really want a task to be dependent on another parent running task, I prefer to specify it explicitly to ease code reading rather than rely on call stack magic.

I know this question may sound quite subjective, but I can&#39;t find a good objective argument as to why this behavior is as it. I&#39;m sure I&#39;m missing something here: that&#39;s why I&#39;m turning to you.

  [1]: http://msdn.microsoft.com/en-us/library/system.threading.tasks.taskscheduler.current.aspx
  [2]: http://msdn.microsoft.com/en-us/library/system.threading.tasks.taskscheduler.default.aspx

Why is TaskScheduler.Current the default TaskScheduler?

The method should work like `Math.Max()`, but take 3 or more `int` parameters.

Is there a method to find the max of 3 numbers in C#?

I have a curious problem with ASP.NET MVC3 client-side validation. I have the following class:

    public class Instrument : BaseObject
    {
        public int Id { get; set; }

        [Required(ErrorMessage = &quot;Name is required.&quot;)]
        [MaxLength(40, ErrorMessage = &quot;Name cannot be longer than 40 characters.&quot;)]
        public string Name { get; set; }
    }

From my view:

    &lt;div class=&quot;editor-field&quot;&gt;
        @Html.EditorFor(model =&gt; model.Name)
        @Html.ValidationMessageFor(model =&gt; model.Name)
    &lt;/div&gt;


And here&#39;s the generated HTML I get for the textbox for this field:

    &lt;input class=&quot;text-box single-line&quot; data-val=&quot;true&quot; data-val-required=&quot;Name is required.&quot; id=&quot;Name&quot; name=&quot;Name&quot; type=&quot;text&quot; value=&quot;&quot;&gt;

No sign of the `MaxLengthAttribute`, but everything else seems to be working.

Any ideas what&#39;s going wrong?


MaxLength Attribute not generating client-side validation attributes

The reason for interfaces truly eludes me. From what I understand, it is kind of a work around for the non-existent multi-inheritance which doesn&#39;t exist in C# (or so I was told).

All I see is, you predefine some members and functions, which then have to be re-defined in the class again. Thus making the interface redundant. It just feels like syntactic… well, junk to me (Please no offense meant. Junk as in useless stuff).

In the example given below taken from a different C# interfaces thread on stack overflow, I would just create a base class called Pizza instead of an interface.

easy example (taken from a different stack overflow contribution)

    public interface IPizza
    {
        public void Order();
    }

    public class PepperoniPizza : IPizza
    {
        public void Order()
        {
            //Order Pepperoni pizza
        }
    }

    public class HawaiiPizza : IPizza
    {
        public void Order()
        {
            //Order HawaiiPizza
        }
    }


Interfaces — What&#39;s the point?

I want to convert a **std::string** into a **char*** or **char[]** data type.

    std::string str = &quot;string&quot;;
    char* chr = str;

Results in: **“error: cannot convert ‘std::string’ to ‘char’ ...”**.

What methods are there available to do this?

std::string to char*

I am getting an int value from one of the analog pins on my Arduino. How do I concatenate this to a `String` and then convert the `String` to a `char[]`?

It was suggested that I try `char msg[] = myString.getChars();`, but I am receiving a message that `getChars` does not exist.


Converting an int or String to a char array on Arduino

I have a char array:

    char[] a = {&#39;h&#39;, &#39;e&#39;, &#39;l&#39;, &#39;l&#39;, &#39;o&#39;, &#39; &#39;, &#39;w&#39;, &#39;o&#39;, &#39;r&#39;, &#39;l&#39;, &#39;d&#39;};

My current solution is to do 

    String b = new String(a);

But surely there is a better way of doing this?


How to convert a char array back to a string?

How do I parse a `String` value to a `char` type, in Java?  

I know how to do it to int and double (for example `Integer.parseInt(&quot;123&quot;)`).
Is there a class for Strings and Chars?



How to convert/parse from String to char in java?

I am retrieving a lot of information in a list, linked to a database and I want to create a string of groups, for someone who is connected to the website.

I use this to test but this is not dynamic, so it is really bad:

    string strgroupids = &quot;6&quot;;


I want to use this now. But the string returned is something like `1,2,3,4,5,`

  
    groupIds.ForEach((g) =&gt;
    {
        strgroupids = strgroupids  + g.ToString() + &quot;,&quot;;
        strgroupids.TrimEnd(&#39;,&#39;);
    });

    strgroupids.TrimEnd(new char[] { &#39;,&#39; });


I want to delete the `,` after the `5` but it&#39;s definitely not working.        


Content Type	Original Author	Original Content on Stackoverflow
Question	장선민	View Question on Stackoverflow
Solution 1 - C#	SLaks	View Answer on Stackoverflow
Solution 2 - C#	kurdtpage	View Answer on Stackoverflow
Solution 3 - C#	Dan Witkowski	View Answer on Stackoverflow
Solution 4 - C#	Victor	View Answer on Stackoverflow

What is this char? 65279 ''

C# Problem Overview

C# Solutions

Solution 1 - C#

Solution 2 - C#

Solution 3 - C#

Solution 4 - C#

how to accept multiple parameters from returning function in groovy

Android - Share on Facebook, Twitter, Mail, ecc

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