Although currently a tick is 100 nanoseconds, it is best not to rely on this as an absolute. Rather, use &#39;`TimeSpan.TicksPerSecond`&#39; (or any of the other TicksPerXxx member values)

The [tick](http://msdn.microsoft.com/en-us/library/system.timespan.ticks.aspx) is the unit of granularity for the .NET [DateTime](http://msdn.microsoft.com/en-us/library/system.datetime.aspx) and [TimeSpan](http://msdn.microsoft.com/en-us/library/system.timespan.aspx) value types.

It has the following common conversions:

    1 tick = 100 nanoseconds
           = 0.1 microseconds
           = 0.0001 milliseconds
           = 0.0000001 seconds


To quote [MSDN](http://msdn.microsoft.com/en-us/library/system.timespan.ticks.aspx):

&gt; The **smallest unit** of time is the tick, which is **equal to 100 nanoseconds**.

Metrology fail.

Note that, although the theoretical resolution of DateTime.Now is quite high, the resolution - ie how often it is updated - it quite a bit lower.

Apparently, on modern systems, DateTime.Now has a resolution of 10 milliseconds... See [msdn.microsoft.com/en-us/library/system.datetime.now.aspx][1]


  [1]: http://msdn.microsoft.com/en-us/library/system.datetime.now.aspx

How important are Design Patterns really?  

I think the earlier generation of programmers didn&#39;t use Design Patterns that much (people who graduated in the 80s and before mid 90s).  Do the recent graduate know it in general and use it a lot more?


How important are Design Patterns really?

&gt; **Possible Duplicate:**  
&gt; [What is the difference between the following casts in c#?](https://stackoverflow.com/questions/702234/what-is-the-difference-between-the-following-casts-in-c)  


In C#, is a there difference between casting an object or using the `as` keyword? Hopefully this code will illustrate what I mean...

    String text = &quot;Hello hello&quot;;
    Object obj = text; 

    String originalCast = ((String)obj).ToUpper();
    String originalAs = (obj as String).ToUpper();

Thanks

**:)**

C# difference between casting and as?

How long is a .NET DateTime/TimeSpan tick?

<p>How long is a .NET DateTime/TimeSpan tick?</p>


I have two objects of the same type, and I want to loop through the public properties on each of them and alert the user about which properties don&#39;t match.

Is it possible to do this without knowing what properties the object contains?

Compare two objects&#39; properties to find differences?

I want to create a varchar column in SQL that should contain `N&#39;guid&#39;` while `guid` is a generated GUID by .NET ([Guid.NewGuid][1]) - class System.Guid.

What is the length of the `varchar` I should expect from a GUID?
Is it a static length?

Should I use `nvarchar` (will GUID ever use Unicode characters)?

    varchar(Guid.Length)

PS. I don&#39;t want to use a SQL row guid data-type. I am just asking what is `Guid.MaxLength`.

  [1]: https://docs.microsoft.com/en-us/dotnet/api/system.guid.newguid


What is the string length of a GUID?

What is the most exact way of seeing how long something, for example a method call, took in code?

The easiest and quickest I would guess is this:

    DateTime start = DateTime.Now;
    {
        // Do some work
    }
    TimeSpan timeItTook = DateTime.Now - start;

But how exact is this? Are there better ways?

Exact time measurement for performance testing

I&#39;m building a web app that attempts to install/upgrade the database on App_Start.
Part of the installation procedure is to ensure that the database has the asp.net features installed. For this I am using the System.Web.Management.SqlServices object.

My intention is to do all the database work within an SQL transaction and if any of it fails, roll back the transaction and leave the database untouched.

the SqlServices object has a method &quot;Install&quot; that takes a ConnectionString but not a transaction. So instead I use SqlServices.GenerateApplicationServicesScripts like so:

    string script = SqlServices.GenerateApplicationServicesScripts(true, SqlFeatures.All, _connection.Database);
    SqlHelper.ExecuteNonQuery(transaction, CommandType.Text, script, ...);

and then I use the SqlHelper from the Enterprise Library.

but this throws an Exception with a butt-load of errors, a few are below

    Incorrect syntax near &#39;GO&#39;.
    Incorrect syntax near &#39;GO&#39;.
    Incorrect syntax near &#39;GO&#39;.
    Incorrect syntax near &#39;GO&#39;.
    Incorrect syntax near the keyword &#39;USE&#39;.
    Incorrect syntax near the keyword &#39;CREATE&#39;.
    Incorrect syntax near &#39;GO&#39;.
    The variable name &#39;@cmd&#39; has already been declared. Variable names must be unique within a query batch or stored procedure.

I&#39;m presuming it&#39;s some issue with using the GO statement within an SQL Transaction.

How can I get this generated script to work when executed in this way.

Using &quot;GO&quot; within a transaction

Is there a simple way to get a system&#39;s uptime using C#?

Retrieve system uptime using C#

Having a look on the PHP documentation, the following two methods of the `DateTime` object would both seem to solve my problem:

- &lt;a href=&quot;http://au.php.net/manual/en/datetime.diff.php&quot;&gt;DateTime::diff&lt;/a&gt; : Get the difference and use that to determine which is more ancient.
- &lt;a href=&quot;http://au.php.net/manual/en/datetime.gettimestamp.php&quot;&gt;DateTime::getTimestamp&lt;/a&gt; : Get the UNIX timestampt and compare those.

Both these methods are marked in the &lt;a href=&quot;http://au.php.net/datetime&quot;&gt;doco&lt;/a&gt; as being available in version &gt;= 5.3 (and, not surprisingly, if I try to call them I find they don&#39;t exist). I can&#39;t find any specific documentation for 5.2.8 so I am not sure if there are equivalent methods in my version.  I have &lt;a href=&quot;http://www.google.com.au/search?q=compare+DateTime+PHP&amp;ie=utf-8&amp;oe=utf-8&amp;aq=t&amp;rls=org.mozilla:en-US:official&amp;client=firefox-a&quot;&gt;Googled&lt;/a&gt; the problem and found an eclectic range of solutions, none of which answer my very simple requirements:

- How do I compare two DateTime objects?
- Where can I find the doco for previous PHP versions? Specifically version 5.2.8?

For some context, I have the following code:

    $st_dt = new DateTime(verifyParam (&#39;start_date&#39;));
    $end_dt = new DateTime(verifyParam (&#39;end_date&#39;));

    // is the end date more ancient than the start date?
    if ($end_dt &lt; $start_dt) 

Apparently there is no comparison operator on this guy.  

Edit
---

*Apparently* my assumptions were completely false (thanks Milen for illustrating this so effectively).  There is a comparison operator and it works just fine thanks.  Sometimes I really miss a compiler.  The bug is in the code above, I am sure you will find it much faster than I did :).


How do I compare two DateTime objects in PHP 5.2.8?

I&#39;m getting a datetime string in a format like &quot;2009-05-28T16:15:00&quot; (this is ISO 8601, I believe). One hackish option seems to be to parse the string using `time.strptime` and passing the first six elements of the tuple into the datetime constructor, like:

    datetime.datetime(*time.strptime(&quot;2007-03-04T21:08:12&quot;, &quot;%Y-%m-%dT%H:%M:%S&quot;)[:6])

I haven&#39;t been able to find a &quot;cleaner&quot; way of doing this. Is there one?



How do I translate an ISO 8601 datetime string into a Python datetime object?

How can I create a Timestamp with the date 23/09/2007? 

Java Timestamp - How can I create a Timestamp with the date 23/09/2007?

How does one go about finding the month name in C#? I don&#39;t want to write a huge `switch` statement or `if` statement on the month `int`. In VB.Net you can use `MonthName()`, but what about C#?

 

How to get the month name in C#?

What is the best way of representing a `DateTime` in Excel? We use Syncfusions [Essential XlsIO][1] to output values to an Excel document which works great. But I can&#39;t figure out how to display a `DateTime` in a column. Not when doing it myself directly in Excel either. Is it impossible? Do I have to use a separate date and a time column? I really wish I didn&#39;t, cause it kind of breaks sorting etc... unless Excel have something clever going on to fix that...


  [1]: http://www.syncfusion.com/products/back-office/xlsio

How to represent a DateTime in Excel

Is there a cross-platform way to get the current date and time in C++?

How to get current time and date in C++?

Suppose I have the value 6/22/2009 10:00:00 AM. How do I get only 10:00 Am from this date time.

How to get only time from date-time C#

Why is

&gt; 1 January 1970 00:00:00

considered the *epoch time*?

Why is 1/1/1970 the &quot;epoch time&quot;?

I can give it floating point numbers, such as

    time.sleep(0.5)

but how accurate is it? If i give it

    time.sleep(0.05)

will it really sleep about 50 ms?

How accurate is python&#39;s time.sleep()?

What&#39;s the best way to set `Time.now` for the purpose of testing time-sensitive methods in a unit test?


How to fake Time.now?

Using .NET 3.5

I want to determine if the current time falls in a time range.

So far I have the currentime:

    DateTime currentTime = new DateTime();
    currentTime.TimeOfDay;

I&#39;m blanking out on how to get the time range converted and compared.
Would this work?

    if (Convert.ToDateTime(&quot;11:59&quot;) &lt;= currentTime.TimeOfDay 
        &amp;&amp; Convert.ToDateTime(&quot;13:01&quot;) &gt;= currentTime.TimeOfDay)
    {
       //match found
    }
                

UPDATE1: Thanks everyone for your suggestions.  I wasn&#39;t familiar with the TimeSpan function.

Find if current time falls in a time range

In C#/.NET `TimeSpan` has `TotalDays`, `TotalMinutes`, etc. but I can&#39;t figure out a formula for total months difference. Variable days per month and leap years keep throwing me off. How can I get **TotalMonths**?

**Edit** Sorry for not being more clear: I know I can&#39;t actually get this from `TimeSpan` but I thought using `TotalDays` and `TotalMinutes` would be a good example to express what I was looking for ... except I&#39;m trying to get Total Months.

Example: Dec 25, 2009 - Oct 6, 2009 = 2 TotalMonths. Oct 6th to Nov 5th equals 0 months. On Nov 6th, 1 month. On Dec 6th, 2 months

calculating the difference in months between two dates

Both of these generate an error saying they must be a compile-time constant:

    void Foo(TimeSpan span = TimeSpan.FromSeconds(2.0))
    void Foo(TimeSpan span = new TimeSpan(2000))

First of all, can someone explain why these values can&#39;t be determined at compile time? And is there a way to specify a default value for an optional TimeSpan object?

C# 4.0: Can I use a TimeSpan as an optional parameter with a default value?

&gt; **Possible Duplicate:**  
&gt; [How do I calculate someone&amp;rsquo;s age in C#?](https://stackoverflow.com/questions/9/how-do-i-calculate-someones-age-in-c)  

&lt;!-- End of automatically inserted text --&gt;

I want to calculate basically the age of employees -  So we have DOB for each employee, So on 
the C# Side I want to do something like this -

    int age=Convert.Int32(DateTime.Now-DOB);

I can use days and manipulate then get the age...but I wanted to know if there something I can use directly to get the number of years.


Calculate the difference between two dates and get the value in years?

I have a collection of objects that include a TimeSpan variable:

    MyObject
    { 
        TimeSpan TheDuration { get; set; }
    }

I want to use LINQ to sum those times.
Of course, (from r in MyCollection select r.TheDuration).Sum(); doesn&#39;t work!

I&#39;m thinking of changing the datatype of TheDuration to an int and then summing it and converting the sum to a TimeSpan. That will be messy because each TheDuration in my collection is used in as a timespan somewhere else.

Any suggestion on this summation?

Content Type	Original Author	Original Content on Stackoverflow
Question	Jason Kresowaty	View Question on Stackoverflow
Solution 1 - .Net	jerryjvl	View Answer on Stackoverflow
Solution 2 - .Net	Jason Kresowaty	View Answer on Stackoverflow
Solution 3 - .Net	Colonel Panic	View Answer on Stackoverflow
Solution 4 - .Net	utunga	View Answer on Stackoverflow

How long is a .NET DateTime/TimeSpan tick?

.Net Problem Overview

.Net Solutions

Solution 1 - .Net

Solution 2 - .Net

Solution 3 - .Net

Solution 4 - .Net

C# difference between casting and as?

How important are Design Patterns really?

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