From the [MSDN docs][1]:

&gt; The Application_Start and Application_End methods are special methods that do not represent HttpApplication events. ASP.NET **calls them once for the lifetime of the application domain, not for each HttpApplication instance**. 

Init:

&gt; Called **once for every instance of the
&gt; HttpApplication** class after all
&gt; modules have been created.

UPDATE: if you need to make sure a certain code is called only once in the app. lifecycle, Application_Start is a better solution. Examples: configuring log4net?


  [1]: http://msdn.microsoft.com/en-us/library/ms178473%28v=vs.100%29

Yes 

There are differences between them. Application_Start() event is called just one time while Init() method is called on each time when instance of the application is created.

I have `MyClass&lt;T&gt;`.

And then I have this `string s = &quot;MyClass&lt;AnotherClass&gt;&quot;;`. How can I get Type from the string `s`?

One way (ugly) is to parse out the &quot;&lt;&quot; and &quot;&gt;&quot; and do: 
 
    Type acType = Type.GetType(&quot;AnotherClass&quot;);  
    Type whatIwant = typeof (MyClass&lt;&gt;).MakeGenericType(acType);

But is there a cleaner way to get the final type without any parsing, etc.?


How can I get generic Type from a string representation?

An interview question for a .NET 3.5 job is &quot;What is the difference between an iterator and an enumerator&quot;?

This is a core distinction to make, what with LINQ, etc.

Anyway, what is the difference? I can&#39;t seem to find a solid definition on the net. Make no mistake, I can find the meaning of the two terms but I get slightly different answers. What would be the best answer for an interview?

IMO an iterator &quot;iterates&quot; over a collection, and an enumerator provides the functionality to iterate, but this has to be called.

Also, using the yield keyword is said to save state. What exactly is this state? Is there an example of this benefit occurring?

Distinction between iterator and enumerator

I am wondering under what circumstances I should be putting application initialisation code in `Application_Start()` vs `Init()` in my `Global.asax` file?

The distinction between the two doesn&#39;t seem very obvious to me, other than `Application_start` gets called first, then `Init()`. 

 - Why would I use one over the other?
 - Does it really make a difference?
 - What changes in the application state
   between the two events?

So far the only real pointer I can find is that `IHttpModule` only has an `Init()` method, so if what I&#39;m doing may at some point be better suited to implement `IHttpModule` I should use the `Init()` method of `Global.asax`, if nothing else for consistency.

When to use Application_Start vs Init in Global.asax?

I am wondering under what circumstances I should be putting application initialisation code in <code>Application_Start()</code> vs <code>Init()</code> in my <code>Global.asax</code> file?
The distinction between the two doesn't seem very obvious to me, other than <code>Application_start</code> gets called first, then <code>Init()</code>.
<ul>
<li>Why would I use one over the other?</li>
<li>Does it really make a difference?</li>
<li>What changes in the application state
between the two events?</li>
</ul>
So far the only real pointer I can find is that <code>IHttpModule</code> only has an <code>Init()</code> method, so if what I'm doing may at some point be better suited to implement <code>IHttpModule</code> I should use the <code>Init()</code> method of <code>Global.asax</code>, if nothing else for consistency.

I have three values which I have to pass as parameters for e.g., `strID`, `strName` and `strDate`.

I want to redirect these three parameters to another page in `Response.Redirect()`.Can anybody provide me with the correct querystring?

How to pass multiple parameters in a querystring

I&#39;m currently researching methods for storing user roles and permissions for .NET based projects. Some of these projects are web based, some are not. I&#39;m currently struggling to find the best method to achieve what I&#39;m looking for in a consistent, portable way across project types.

Where I&#39;m at, we&#39;re looking to leverage Active Directory as our single point of contact for basic user information. Because of this, we&#39;re looking to not have to maintain a custom database for each application&#39;s users since they are already stored in Active Directory and actively maintained there. Additionally, we don&#39;t want to write our own security model/code if possible and would like to use something pre-existing, like the security application blocks provided by Microsoft.

Some projects require only basic privileges, such as read, write, or no access. Other projects require more complex permissions. Users of those applications might be granted access to some areas, but not others, and their permissions can change across each area. An administration section of the app would control and define this access, **not** the AD tools. 

Currently, we&#39;re using integrated Windows Authentication to perform authentication on our intranet. This works well for finding out basic user information, and I&#39;ve seen that ASP.NET can be extended to provide an Active Directory roles provider, so I can find out any security groups a user belongs to. But, what seems like the downfall of this method to me is that everything is stored in Active Directory, which could lead to a mess to maintain if things grow too big. 

Along this same line, I&#39;ve also heard of Active Directory Lightweight Directory Services, which seems like it could extend our schema and add only application specific attributes and groups. Problem is, I can&#39;t find anything on how this would be done or how this works. There are MSDN articles that describe how to talk to this instance and how to create a new instance, but nothing ever seems to answer my question.

**My question is:** Based on your experience, am I going down the right track? Is what I&#39;m looking to do possible using just Active Directory, or do other tools have to be used?

----------

**Other methods I&#39;ve looked into:**

 - Using multiple web.config files [[stackoverflow][1]]
 - Creating a custom security model and database to manage users across applications


  [1]: https://stackoverflow.com/questions/176338/customer-configurable-asp-net-web-site-security-for-fine-grained-control-of-page

User Group and Role Management in .NET with Active Directory

I seem to be getting a &quot;invalid viewstate&quot; every now and then in the event viewer for my [ASP.NET][1] application.

Most of them (95%) seem to be referencing `ScriptResource.axd` (the application 
uses the [ASP.NET AJAX][2] library).  There is no way I can remove the [Ajax][3] library either as Ajax is used everywhere..

How can I reduce these errors? I&#39;m getting ~ 100-200 errors a day and I have no idea how to fix them! They come from different browsers, different IPs and geographical locations.

It&#39;s difficult for me to reproduce the problem because it barely even happened to me, it has only happened to me 3-4 times out of the blue.


**Error:**

    Process information: 
        Process ID: 4004 
        Process name: w3wp.exe 
        Account name: NT AUTHORITY\NETWORK SERVICE 
     
    Exception information: 
        Exception type: HttpException 
        Exception message: Invalid viewstate. 
     
    Request information: 
        Request URL: http://domainnamehere/ScriptResource.axd?d=W1R6x9VzZ2C9SKnIkOmX9VRLhSjJ3nOF1GSQvPwKS3html 
        Request path: /ScriptResource.axd 
        User host address: 124.177.170.75 
        User:  
        Is authenticated: False 
        Authentication Type:  
        Thread account name: NT AUTHORITY\NETWORK SERVICE 
     
    Thread information: 
        Thread ID: 1 
        Thread account name: NT AUTHORITY\NETWORK SERVICE 
        Is impersonating: False 
        Stack trace:    at System.Web.UI.Page.DecryptStringWithIV(String s, IVType ivType)
       at System.Web.UI.Page.DecryptString(String s)
       at System.Web.Handlers.ScriptResourceHandler.DecryptParameter(NameValueCollection queryString)
       at System.Web.Handlers.ScriptResourceHandler.ProcessRequestInternal(HttpResponse response, NameValueCollection queryString, VirtualFileReader fileReader)
       at System.Web.Handlers.ScriptResourceHandler.ProcessRequest(HttpContext context)
       at System.Web.Handlers.ScriptResourceHandler.System.Web.IHttpHandler.ProcessRequest(HttpContext context)
       at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
       at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean&amp; completedSynchronously)
     
     
    Custom event details: 
     
    For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.


I also get this error every now and then in my .NET code which happens at the same time which might be related:

    Exception raised in GLOBAL.ASAX.Application_Error(): &#39;Padding is invalid and cannot be removed.&#39; at System.Security.Cryptography.RijndaelManagedTransform.DecryptData(Byte[] inputBuffer, Int32 inputOffset, Int32 inputCount, Byte[]&amp; outputBuffer, Int32 outputOffset, PaddingMode paddingMode, Boolean fLast)
       at System.Security.Cryptography.RijndaelManagedTransform.TransformFinalBlock(Byte[] inputBuffer, Int32 inputOffset, Int32 inputCount)
       at System.Security.Cryptography.CryptoStream.FlushFinalBlock()
       at System.Web.Configuration.MachineKeySection.EncryptOrDecryptData(Boolean fEncrypt, Byte[] buf, Byte[] modifier, Int32 start, Int32 length, IVType ivType, Boolean useValidationSymAlgo)
       at System.Web.UI.ObjectStateFormatter.Deserialize(String inputString)

  [1]: http://en.wikipedia.org/wiki/ASP.NET
  [2]: http://en.wikipedia.org/wiki/ASP.NET_AJAX
  [3]: http://en.wikipedia.org/wiki/Ajax_%28programming%29

Erratic Invalid Viewstate issue in a .NET application

What is the difference between SessionState and ViewState in ASP.NET?

What is the difference between SessionState and ViewState?

I am having trouble with Html.ActionLink when I have a route that takes more than one parameter. For example, given the following routes defined in my Global.asax file:

	routes.MapRoute(
	    &quot;Default&quot;,                                              // Route name
	    &quot;{controller}.mvc/{action}/{id}&quot;,                           // URL with parameters
	    new { controller = &quot;Home&quot;, action = &quot;Index&quot;, id = &quot;&quot; }  // Parameter defaults
	);
	
	routes.MapRoute(
	    &quot;Tagging&quot;,
	    &quot;{controller}.mvc/{action}/{tags}&quot;,
	    new { controller = &quot;Products&quot;, action = &quot;Index&quot;, tags = &quot;&quot; }
	);
	
	routes.MapRoute(
	    &quot;SlugsAfterId&quot;,
	    &quot;{controller}.mvc/{action}/{id}/{slug}&quot;,
	    new { controller = &quot;Products&quot;, action = &quot;Browse&quot;, id = &quot;&quot;, slug = &quot;&quot; }
	);

The first two routes work without a problem, but when I try to create an action link to the third route using:

    &lt;%= Html.ActionLink(Html.Encode(product.Name), &quot;Details&quot;, new { id = product.ProductId, slug = Html.Encode(product.Name) }) %&gt;

I end up with a URL like **[site-root]/Details/1?slug=url-slug** whereas I would like the URL to be more like **[site-root]/Details/1/url-slug**

Can anyone see where I am going wrong?

ASP.NET MVC URL Routing with Multiple Route Values

I need to use `Server.MapPath()` to combine some files path that I store in the `web.config`.

However, since `Server.MapPath()` relies on the current HttpContext (I think), I am unable to do this.  When trying to use the method, even though its &quot;available&quot;, I get the following exception:

&gt;Server operation is not available in this context.

Is there another method that can map a web root relative directory such as `~/App_Data/` to the full physical path such as `C:\inetpub\wwwroot\project\App_data\` ?

How can I use Server.MapPath() from global.asax?

I can&#39;t debug global.asax file! 

I have some codes in `Application_Start()` method but when I set a break point in the method, it is ignored! 

Is this normal?

Is it possible to debug Global.asax?

In my .Net 2.0 Asp.net WebForms app, I have my Global.asax containing the following code:

    &lt;%@ Application CodeBehind=&quot;Global.asax.cs&quot; Inherits=&quot;MyNamespace.Global&quot; Language=&quot;C#&quot; %&gt;
However when I build I get an error stating-

&gt; Could not load type &#39;MyNamespace.Global&#39;.

This seems to be because the MyNamespace namespace (defined in the code behind file Global.asax.cs) is not seen by the compiler in the Global.asax file (does not show in R# intellisence..).
This turned out to be a very hard nut to crack... any help will be appreciated!

Note: The Global.asax and the Global.asax.cs are located in the same folder.

Note2: When compiling from the vs prompt with csc it compiles o.k. 

&quot;Could not load type [Namespace].Global&quot; causing me grief

I am starting to use MVC4 Web API project, I have controller with multiple `HttpPost` methods. The Controller looks like the following:

**Controller**

    public class VTRoutingController : ApiController
    {
        [HttpPost]
        public MyResult Route(MyRequestTemplate routingRequestTemplate)
        {
            return null;
        }
    
        [HttpPost]
        public MyResult TSPRoute(MyRequestTemplate routingRequestTemplate)
        {
            return null;
        }
    }

*Here `MyRequestTemplate` represents the template class responsible for handling the Json coming through the request.* 

**Error:**

When I make a request using Fiddler for `http://localhost:52370/api/VTRouting/TSPRoute` or `http://localhost:52370/api/VTRouting/Route`  I get an error: 

&gt; Multiple actions were found that match the request

If I remove one of the above method it works fine.

**Global.asax**

I have tried modifying the default routing table in `global.asax`, but I am still getting the error, I think I have problem in defining routes in global.asax. Here is what I am doing in global.asax. 

    public static void RegisterRoutes(RouteCollection routes)
    {
        routes.MapHttpRoute(
            name: &quot;MyTSPRoute&quot;,
            routeTemplate: &quot;api/VTRouting/TSPRoute&quot;,
            defaults: new { }
        );
    
        routes.MapHttpRoute(
            name: &quot;MyRoute&quot;,
            routeTemplate: &quot;api/VTRouting/Route&quot;,
            defaults: new { action=&quot;Route&quot; }
        );
    }

I am making the request in Fiddler using POST, passing json in RequestBody for MyRequestTemplate.

Content Type	Original Author	Original Content on Stackoverflow
Question	roryf	View Question on Stackoverflow
Solution 1 - asp.net	Igor Brejc	View Answer on Stackoverflow
Solution 2 - asp.net	Abid Mahmood	View Answer on Stackoverflow

When to use Application_Start vs Init in Global.asax?

asp.net Problem Overview

asp.net Solutions

Solution 1 - asp.net

Solution 2 - asp.net

Distinction between iterator and enumerator

How can I get generic Type from a string representation?

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