    DateTime.Now.ToString(&quot;M/d/yyyy&quot;);

&lt;http://msdn.microsoft.com/en-us/library/8kb3ddd4.aspx&gt;



Not to be horribly pedantic, but if you are internationalising the code it might be more useful to have the facility to get the short date for a given culture, e.g.:-

    using System.Globalization;
    using System.Threading;
   
    ...

    var currentCulture = Thread.CurrentThread.CurrentCulture;
    try {
      Thread.CurrentThread.CurrentCulture = CultureInfo.CreateSpecificCulture(&quot;en-us&quot;);
      string shortDateString = DateTime.Now.ToShortDateString();
      // Do something with shortDateString...
    } finally {
      Thread.CurrentThread.CurrentCulture = currentCulture;
    }

Though clearly the &quot;m/dd/yyyy&quot; approach is considerably neater!!

    DateTime.Now.ToString(&quot;dd/MM/yyyy&quot;);

If you want it without the year:

    DateTime.Now.ToString(&quot;MM/DD&quot;);

DateTime.ToString() has a lot of cool format strings:

http://msdn.microsoft.com/en-us/library/aa326721.aspx

    DateTime.Now.Date.ToShortDateString()

is culture specific. 

It is best to stick with:

    DateTime.Now.ToString(&quot;d/MM/yyyy&quot;);


    string today = DateTime.Today.ToString(&quot;M/d&quot;);

    DateTime.Now.Date.ToShortDateString()

I think this is what you are looking for

Or without the year:

    DateTime.Now.ToString(&quot;M/dd&quot;)

I&#39;ve heard that creating a new process on a Windows box is more expensive than on Linux.  Is this true?  Can somebody explain the technical reasons for why it&#39;s more expensive and provide any historical reasons for the design decisions behind those reasons?

Why is creating a new process more expensive on Windows than Linux?

I am aware that in [.NET][1] there are three timer types (see *[Comparing the Timer Classes in the .NET Framework Class Library][2]*). I have chosen a threaded timer as the other types can drift if the main thread is busy, and I need this to be reliable.

The way this timer works in the control of the timer is put on another thread so it can always tick along with the work begin completed on the parent thread when it is not busy.

The issue with this timer in a console application is that while the timer is ticking along on another thread the main thread is not doing anything to the application closes.

I tried adding a `while true` loop, but then the main thread is too busy when the timer does go off.

  [1]: http://en.wikipedia.org/wiki/.NET_Framework
  [2]: http://msdn.microsoft.com/en-us/magazine/cc164015.aspx


Reliable timer in a console application

How do I get today&#39;s date in C# in mm/dd/yyyy format?

I need to set a string variable to today&#39;s date (preferably without the year), but there&#39;s got to be a better way than building it month-/-day one piece at a time.

BTW: I&#39;m in the US so M/dd would be correct, e.g. September 11th is 9/11.

*Note: an answer from kronoz came in that discussed internationalization, and I thought it was awesome enough to mention since I can&#39;t make it an &#39;accepted&#39; answer as well.*

[kronoz&#39;s answer][1]

  [1]: https://stackoverflow.com/questions/32747/how-do-i-get-todays-date-in-c-in-8282008-format#32819 &quot;kronoz&#39;s answer&quot;


How do I get today&#39;s date in C# in mm/dd/yyyy format?

How do I get today's date in C# in mm/dd/yyyy format?
I need to set a string variable to today's date (preferably without the year), but there's got to be a better way than building it month-/-day one piece at a time.
BTW: I'm in the US so M/dd would be correct, e.g. September 11th is 9/11.
Note: an answer from kronoz came in that discussed internationalization, and I thought it was awesome enough to mention since I can't make it an 'accepted' answer as well.
[kronoz's answer][1]
[1]: <a href="https://stackoverflow.com/questions/32747/how-do-i-get-todays-date-in-c-in-8282008-format#32819" target="_blank" rel="noopener noreferrer">https://stackoverflow.com/questions/32747/how-do-i-get-todays-date-in-c-in-8282008-format#32819</a> "kronoz's answer"

There are two weird operators in C#:

  - the [true operator][1]
  - the [false operator][2]

If I understand this right these operators can be used in types which I want to use instead of a boolean expression and where I don&#39;t want to provide an implicit conversion to bool.

Let&#39;s say I have a following class:

        public class MyType
        {
            public readonly int Value;

            public MyType(int value)
            {
                Value = value;
            }

            public static bool operator true (MyType mt)
            {
                return  mt.Value &gt; 0;
            }

            public static bool operator false (MyType mt)
            {
                return  mt.Value &lt; 0;
            }

        }

So I can write the following code:

        MyType mTrue = new MyType(100);
        MyType mFalse = new MyType(-100);
        MyType mDontKnow = new MyType(0);

        if (mTrue)
        {
             // Do something.
        }

        while (mFalse)
        {
            // Do something else.
        }

        do
        {
            // Another code comes here.
        } while (mDontKnow)

However for all the examples above only the true operator is executed. So what&#39;s the false operator in C# good for?

*Note: More examples can be found [here][3], [here][4] and [here][5].*

  [1]: http://msdn.microsoft.com/en-us/library/6x6y6z4d.aspx
  [2]: http://msdn.microsoft.com/en-us/library/6292hy1k.aspx
  [3]: http://www.java2s.com/Tutorial/CSharp/0160__Operator-Overload/truefalseoperatorforComplex.htm
  [4]: http://www.java2s.com/Tutorial/CSharp/0160__Operator-Overload/OverloadtrueandfalseforTwoDimension.htm
  [5]: http://www.java2s.com/Tutorial/CSharp/0160__Operator-Overload/trueandfalseoperator.htm




What&#39;s the false operator in C# good for?

I want to apply an XSLT Stylesheet to an XML Document using C# and write the output to a File.


How to apply an XSLT Stylesheet in C#

**Is there anything built into the core C# libraries that can give me an immutable Dictionary?**  

Something along the lines of *Java&#39;s*:

    Collections.unmodifiableMap(myMap);

And just to clarify, I am not looking to stop the keys / values themselves from being changed, just the structure of the Dictionary.  I want something that fails fast and loud if any of IDictionary&#39;s mutator methods are called (`Add, Remove, Clear`).

Does C# have a way of giving me an immutable Dictionary?

I have always used `||` (two pipes) in OR expressions, both in C# and PHP. Occasionally I see a single pipe used: `|`. What is the difference between those two usages? Are there any caveats when using one over the other or are they interchangeable?

What is the difference between the | and || or operators?

I&#39;m working on a project using the [ANTLR][1] parser library for C#.  I&#39;ve built a grammar to parse some text and it works well.  However, when the parser comes across an illegal or unexpected token, it throws one of many exceptions.  The problem is that in some cases (not all) that my try/catch block won&#39;t catch it and instead stops execution as an unhandled exception.

The issue for me is that I can&#39;t replicate this issue anywhere else but in my full code.  The call stack shows that the exception definitely occurs within my try/catch(Exception) block.  The only thing I can think of is that there are a few ANTLR assembly calls that occur between my code and the code throwing the exception and this library does not have debugging enabled, so I can&#39;t step through it.  I wonder if non-debuggable assemblies inhibit exception bubbling?  The call stack looks like this; external assembly calls are in Antlr.Runtime:

&lt;pre&gt;
	Expl.Itinerary.dll!TimeDefLexer.mTokens() Line 1213	C#
 	Antlr3.Runtime.dll!Antlr.Runtime.Lexer.NextToken() + 0xfc bytes	
 	Antlr3.Runtime.dll!Antlr.Runtime.CommonTokenStream.FillBuffer() + 0x22c bytes	
 	Antlr3.Runtime.dll!Antlr.Runtime.CommonTokenStream.LT(int k = 1) + 0x68 bytes
 	Expl.Itinerary.dll!TimeDefParser.prog() Line 109 + 0x17 bytes	C#
	Expl.Itinerary.dll!Expl.Itinerary.TDLParser.Parse(string Text = &quot;&quot;, Expl.Itinerary.IItinerary Itinerary = {Expl.Itinerary.MemoryItinerary}) Line 17 + 0xa bytes	C#
&lt;/pre&gt;

The code snippet from the bottom-most call in Parse() looks like:

         try {
            // Execution stopped at parser.prog()
            TimeDefParser.prog_return prog_ret = parser.prog();
            return prog_ret == null ? null : prog_ret.value;
         }
         catch (Exception ex) {
            throw new ParserException(ex.Message, ex);
         }

To me, a catch (Exception) clause should&#39;ve captured any exception whatsoever.  Is there any reason why it wouldn&#39;t?

**Update:** I traced through the external assembly with Reflector and found no evidence of threading whatsoever.  The assembly seems to just be a runtime utility class for ANTLR&#39;s generated code.  The exception thrown is from the TimeDefLexer.mTokens() method and its type is NoViableAltException, which derives from RecognitionException -&gt; Exception.  This exception is thrown when the lexer cannot understand the next token in the stream; in other words, invalid input.  This exception is SUPPOSED to happen, however it should&#39;ve been caught by my try/catch block.

Also, the rethrowing of ParserException is really irrelevant to this situation.  That is a layer of abstraction that takes any exception during parse and convert to my own ParserException.  The exception handling problem I&#39;m experiencing is never reaching that line of code.  In fact, I commented out the &quot;throw new ParserException&quot; portion and still received the same result.

One more thing, I modified the original try/catch block in question to instead catch NoViableAltException, eliminating any inheritance confusion.  I still received the same result.

Someone once suggested that sometimes VS is overactive on catching handled exceptions when in debug mode, but this issue also happens in release mode.

Man, I&#39;m still stumped!  I hadn&#39;t mentioned it before, but I&#39;m running VS 2008 and all my code is 3.5.  The external assembly is 2.0.  Also, some of my code subclasses a class in the 2.0 assembly.  Could a version mismatch cause this issue?

**Update 2:** I was able to eliminate the .NET version conflict by porting relevant portions of my .NET 3.5 code to a .NET 2.0 project and replicate the same scenario.  I was able to replicate the same unhandled exception when running consistently in .NET 2.0.

I learned that ANTLR has recently released 3.1.  So, I upgraded from 3.0.1 and retried.  It turns out the generated code is a little refactored, but the same unhandled exception occurs in my test cases.

**Update 3:**
I&#39;ve replicated this scenario in a [simplified VS 2008 project][2].  Feel free to download and inspect the project for yourself.  I&#39;ve applied all the great suggestions, but have not been able to overcome this obstacle yet.

If you can find a workaround, please do share your findings.  Thanks again!


  [1]: http://antlr.org
  [2]: http://www.explodingcoder.com/cms/files/TestAntlr-3.1.zip

---

Thank you, but VS 2008 automatically breaks on unhandled exceptions.  Also, I don&#39;t have a Debug-&gt;Exceptions dialog.  The NoViableAltException that is thrown is fully intended, and designed to be caught by user code.  Since it is not caught as expected, program execution halts unexpectedly as an unhandled exception.

The exception thrown is derived from Exception and there is no multi-threading going on with ANTLR.



Why is .NET exception not caught by try/catch block?

I&#39;m creating an application which lets you define events with a time frame.  I want to automatically fill in the end date when the user selects or changes the start date.  I can&#39;t quite figure out, however, how to get the difference between the two times, and then how to create a new end Date using that difference.

How do I get the difference between two Dates in JavaScript?

Is there a way using Python&#39;s standard library to easily determine (i.e. one function call) the last day of a given month?

If the standard library doesn&#39;t support that, does the dateutil package support this?

How to get the last day of the month?

I have a `String` representation of a date that I need to create a `Date` or `Calendar` object from. I&#39;ve looked through `Date` and `Calendar` APIs but haven&#39;t found anything that can do this other than creating my own ugly parse method. I know there must be a way, does anyone know of a solution?

How to convert a date String to a Date or Calendar object?

I am looking for a way to delete all files older than 7 days in a batch file.  I&#39;ve searched around the web, and found some examples with hundreds of lines of code, and others that required installing extra command line utilities to accomplish the task.

Similar things can be [done in BASH][1] in just a couple lines of code. It seems that something at least remotely easy could be done for batch files in Windows. I&#39;m looking for a solution that works in a standard Windows command prompt, without any extra utilities. Please no PowerShell or Cygwin either.

  [1]: https://stackoverflow.com/questions/25785/delete-all-but-the-most-recent-x-files-in-bash

Batch file to delete files older than N days

I&#39;m trying to write a regular expression that validates a date.  The regex needs to match the following

  - M/D/YYYY
  - MM/DD/YYYY
  - Single digit months can start with a leading zero (eg: 03/12/2008)
  - Single digit days can start with a leading zero (eg: 3/02/2008)
  - CANNOT include February 30 or February 31 (eg: 2/31/2008)

So far I have 

    ^(([1-9]|1[012])[-/.]([1-9]|[12][0-9]|3[01])[-/.](19|20)\d\d)|((1[012]|0[1-9])(3[01]|2\d|1\d|0[1-9])(19|20)\d\d)|((1[012]|0[1-9])[-/.](3[01]|2\d|1\d|0[1-9])[-/.](19|20)\d\d)$

This matches properly EXCEPT it still includes 2/30/2008 &amp; 2/31/2008.

Does anyone have a better suggestion?

**Edit:** I found [the answer][1] on RegExLib

    ^((((0[13578])|([13578])|(1[02]))[\/](([1-9])|([0-2][0-9])|(3[01])))|(((0[469])|([469])|(11))[\/](([1-9])|([0-2][0-9])|(30)))|((2|02)[\/](([1-9])|([0-2][0-9]))))[\/]\d{4}$|^\d{4}$

It matches all valid months that follow the MM/DD/YYYY format.

Thanks everyone for the help.


  [1]: http://regexlib.com/REDetails.aspx?regexp_id=112


Content Type	Original Author	Original Content on Stackoverflow
Question	Keng	View Question on Stackoverflow
Solution 1 - C#	Joel Coehoorn	View Answer on Stackoverflow
Solution 2 - C#	ljs	View Answer on Stackoverflow
Solution 3 - C#	Corin Blaikie	View Answer on Stackoverflow
Solution 4 - C#	FlySwat	View Answer on Stackoverflow
Solution 5 - C#	Corin Blaikie	View Answer on Stackoverflow
Solution 6 - C#	Billy Jo	View Answer on Stackoverflow
Solution 7 - C#	Josh Mein	View Answer on Stackoverflow
Solution 8 - C#	EBGreen	View Answer on Stackoverflow

How do I get today's date in C# in mm/dd/yyyy format?

C# Problem Overview

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Solution 1 - C#

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Solution 8 - C#

Reliable timer in a console application

Why is creating a new process more expensive on Windows than Linux?

Attributions