What is IIS Metabase? How to edit IIS metabase? How to backup IIS metabase file?

IIS metabase is the repository of the configuration values that are set in the Internet Information Server (IIS). The IIS metabase in an XML file. It may be controlled through program or manually too.

In order to edit IIS metabase entries, the user needs to have administrative rights on the system. To do this, in run window, type "inetmgr". Browse to "Local Computer" and right click it. Click on "Properties". Select the "Enable Direct Metabase Edit" check box.

Many times, due to the existence of multiple versions of .NET framework, some settings in the IIS metabase may get affected and cause your program not to run. For such scenarios, you may take a backup of the IIS metabase XML file and recover it. To create a portable backup, open run window and type "inetmgr". Next browse to "Local Computer" and go to "All Tasks". Next, click on Backup/Restore Configuration. Next, click on "Create Backup". In the textbox box for Configuration Backup name, type a name for your backup file. Also select the encrypt backup option and type a password. To finish the process, click "OK".

Describe the Provider Model in ASP.NET 2.0?

The Provider model in ASP.NET 2.0 is based on the Provider Design Pattern that was created in the year 2002 and later implemented in the .NET Framework 2.0.

The Provider Model supports automatic creation of users and their respective roles by creating entries of them directly in the SQL Server (May even use MS Access and other custom data sources). So actually, this model also supports automatically creating the user table's schema.

The Provider model has 2 security providers in it: Membership provider and Role Provider. The membership provider saves inside it the user name (id) and corresponding passwords, whereas the Role provider stores the Roles of the users.

For SQL Server, the SqlMembershipProvider is used, while for MS Access, the AccessMembershipProvider is used. The Security settings may be set using the website adminstration tool. Automatically, the AccessMembershipProvider creates a Microsoft Access database file named aspnetdb.mdb inside the application's App_Data folder. This contains 10 tables.

Explain about Generics?

Generics are not a completely new construct; similar concepts exist with other languages. For example, C++ templates can be compared to generics. However, there's a big difference between C++ templates and .NET generics. With C++ templates the source code of the template is required when a template is instantiated with a specific type. Contrary to C++ templates, generics are not only a construct of the C# language; generics are defined with the CLR. This makes it possible to instantiate generics with a specific type in Visual Basic even though the generic class was defined with C#.

Interview Questions on Cascading Style Sheets

Click here for all C# Interview Questions

Click here for all ASP.NET Interview Questions

What are the 2 ways provided by ASP.NET to format output in a Web application?
1. Use cascading style sheets (CSS) to control the appearance of elements on a Web form.These styles can set the color, size, font, and behavior of the HTML elements on a Web page.

2. Use Extensible Stylesheet Language Transformations (XSLT) to convert information from an Extensible Markup Language (XML) file to HTML output and position that information on a Web form. XSLT puts data from the XML file into HTML elements and applies styles to those elements.

What are Cascading style sheets?
Cascading style sheets (CSS) collect and organize all of the formatting information applied to HTML elements on a Web form. Because they keep this information in a single location, style sheets make it easy to adjust the appearance of Web applications.
What are the 3 levels at which formatting can be applied with in a web application?
1. Styles can be defined in a style sheet file. Styles in a style sheet can be applied to all webforms referencing the style sheet.

2. You can also define styles in the page�s head element. These styles can be applied to all elements on the current page.

3. You can also define styles inline, in the HTML tag itself. Inline styles are applicable only to the HTML element in which these styles are defined.

Inline formatting takes precedence over local formatting, which, in turn, takes precedence over global formatting. These precedence rules are the reason style sheets are referred to as cascading.

What are the advantages of storing style definitions in a style sheet file (.css) rather than locally in each Web form or inline with each HTML element?
1. Formatting can be maintained in one location so that you make changes only once for an entire application.

2. Several sets of parallel formatting rules can be maintained in separate style sheets for formatting output on different devices or for different user needs. For example, an application might provide standard, enlarged-type, and printer-friendly style sheets that the user can select at run time.

3. In general, you should use page and inline styles only when you have a really good reason to override the global styles. Relying heavily on page and inline styles can make it difficult to maintain the formatting in a Web application.
What HTML element is used to reference a style sheet on webform?To reference a style sheet on webform you must add a link element to the page�s head element, as shown below.
<link href="Styles.css" type="text/css" rel="stylesheet">What is the use of Style Builder?
Style Builder is used to change the appearance of any of the styles in a style sheet. Changes to the style sheet change the appearance of all Web forms that reference that style sheet.
How do you modify a style sheet using style builder?To modify a style sheet using style builder, follow these steps:

1. Open the style sheet in Visual Studio. Visual Studio .NET displays the style definitions in the Document window and an outline of the style sheet in the Tool window

2. Select the style to modify from the Tool window. Visual Studio .NET displays the definition for that style in the Document window.

3. Right-click in the style definition or right-click the style in the Tool window, and select Build Style from the shortcut menu. Visual Studio .NET displays the Style Builder Wizard.

4. Use the Style Builder to compose the formatting that you want to add or modify in the selected style, and then click OK.

5. When you have finished, you�ll see that the Style Builder adds the new or modified style attributes to the style definition.
Can you apply styles using class names or element IDs?Yes, Using class names allows you to apply a single style to a number of different elements or to style the same element differently, depending on how the element is used. Using element IDs allows you to apply a style to a unique element on one or more Web forms.

When you create a style rule for a class, Visual Studio .NET adds a style definition to the style sheet using a .classname identifier.

You apply the style class to HTML elements by using the class attribute. You apply the style to server controls by using the CssClass attribute.
Can you change style sheets at run time?Yes.

Click here for all C# Interview Questions

Click here for all ASP.NET Interview Questions

String manipulation

Click here for all C# Interview Questions

Click here for all ASP.NET Interview Questions

Questions:
Please write a sample program that parses the string into a series of substrings where the delimiter between the substrings is "^*!%~" and then reassembles the strings and delimiters into a single new string where each of the substrings is in the reverse order from the original string. The method must return the final string.Original String:Token A^*!%~Token B^*!%~Token C^*!%~Token D^*!%~Token E

Output String:
Token E^*!%~Token D^*!%~Token C^*!%~Token B^*!%~Token AThe code sample below shows how to solve the above question:using System;
using System.Text;
namespace GenericsSample
{
class Program
{
static void Main()
{
string strOriginalString = "Token A^*!%~Token B^*!%~Token C^*!%~Token D^*!%~Token E";
string[] strSeperator = new string[1];
strSeperator[0] = "^*!%~";

string[] strArrayIndividualStrings = strOriginalString.Split(strSeperator, StringSplitOptions.RemoveEmptyEntries);

int intLengthOfStringArray = strArrayIndividualStrings.Length;

StringBuilder sbOutputString = new StringBuilder();
for (int i = (intLengthOfStringArray - 1); i >= 0; i--)
{
sbOutputString.Append(strArrayIndividualStrings[i] + strSeperator[0]);
}
Console.WriteLine("Original String : " + strOriginalString);
Console.WriteLine("Output String : " + sbOutputString.ToString());
Console.ReadLine();
}
}
}

Explanation of the above sample program:
1. We take the original string into a string variable strOriginalString. I named this variable as strOriginalString. str indicates that the variable is of string datatype. This will give a good impression to the person who reviews your code bcos you are following the coding standards.

2. I then store the string delimiter "^*!%~" in strSeperator variable. strSeperator is of string array data type. This is bcos the split function expects string array or character array as seprator.

3. I then split the strOriginalString into a string array using the split function.

4. I created a variable sbOutputString to store the Output string. sbOutputString data type is StringBuilder.

5. I then loop thru the array from the highest index to 0 and retrieve the individual strings and append to the sbOutputString. As the output string is changing as we loop thru the array it is good to use StringBuilder rather than System.String. Strings of type System.Text.StringBuilder are mutable where as strings of type System.String are immutable. If a string is manipulated many times always use StringBuilder over System.String.

6. Two good things to remember from this example are, follow the coding standards in naming the variables and always use StringBuilder class over Strings where we manipulate a particular string many times.

Click here for all C# Interview Questions

Click here for all ASP.NET Interview Questions

ASP.NET Interview Questions on caching application data

Click here for all C# Interview Questions

Click here for all ASP.NET Interview Questions

Which object can used to store frequently used items in the server�s memory for quick retrieval?
Cache object can be used to store frequently used items in the server�s memory for quick retrieval.

Is the cache object available for all web forms with in a web application?
Yes, the Cache object is global, that is, data stored in the Cache object is available anywhere within a Web application. In this way, the Cache object is very similar to the intrinsic Application object.

What are the 3 different ways to store data in the Cache object?
Use assignment.
Assigning a value to an unused key in the Cache object automatically creates that key and assigns the value to that key. Assigning a value to a key that already exists replaces the cached value with the assigned value.Use the Insert method.The Insert method uses parameters rather than assignment to create or change cached data. Insert optionally accepts parameters to establish dependencies and set expiration policy.Use the Add method.The Add method is similar to Insert; however, it requires all parameters and returns an object reference to the cached data.

For example, the following Cache statements all add the same item to the cache:

using System.Web.Caching;
private void Page_Load(object sender, System.EventArgs e)
{
if(!IsPostBack)
{
Cache["NewItem"] = "Some string data";
Cache.Add("NewItem", "Some string data", null, Cache.NoAbsoluteExpiration, System.TimeSpan.FromMinutes(1), CacheItemPriority.Default, null);
Cache.Insert("NewItem", "Some string data");
}
}

What are absoluteExpiration and slidingExpiration parmeters of the Insert and Add methods?
absoluteExpirationA DateTime object that identifies when the data should be removed from the cache. If you�re using sliding expiration, specify Cache.NoAbsoluteExpiration for this parameter.slidingExpirationA TimeSpan object that identifies how long the data should remain in the cache after the data was last accessed. If you�re using absolute expiration, specify Cache.NoSlidingExpiration for this parameter.

Which delegate can be used to notify the application when items are removed from the cache?
onRemoveCallback is used to notify the application when items are removed from the cache.

How do you retrieve the value of a cache item stored in the servers memory?
You can retrieve the value of a cache item stored in the servers memory through the item�s key, just as you do with the Application and Session objects. Because cached items might be removed from memory, you should always check for their existence before attempting to retrieve their value, as shown in the following code:

private void Button1_Click(object sender, EventArgs e)
{
if (Cache["ChachedItem"] == null)
{
Lable1.Text = "Cached Item not found.";
}
else
{
Lable1.Text = Cache["ChachedItem"].ToString();
}
}

Which method can be used to remove data from the cache?
Cache object�s Remove method can be used to remove data from the cache as shown in the following code example / sample.

private void RemoveButton_Click(object sender, System.EventArgs e)
{
Cache.Remove("CachedItem");
}

How do you control how long data is cached?
The Cache object�s Add and Insert method parameters allow you to control how long an item is stored in the server�s memory. In practice, these parameter settings provide only indirect control of how long data remains in memory. If your server runs low on available memory, ASP.NET recovers as much memory as possible from expired cache items. If that�s not enough, ASP.NET will unload unexpired items from the cache based on their priority and when they were last accessed.

What is CacheItemPriority enumeration used for?
CacheItemPriority enumeration is used to set the relative importance of cached items. CacheItemPriority.NotRemoveable has the highest priority and CacheItemPriority.Low has the lowest priority.

Which is the only "event� provided by Cache object?
CacheItemRemoved "event� is the only "event� provided by Cache object.

How do you update the Cache object when data changes?
Items stored in the cache are often copies of data that is stored and maintained elsewhere, such as records in a database. Use the Add and Insert methods� dependency parameter to establish a relationship between a cached data item and an external source, such as a file, a folder, or a group of files.

The dependency parameter accepts a CacheDependency object, which in turn identifies the file, folder, or set of files to watch for changes. ASP.NET checks the time stamp of the items in the CacheDependency object, if one of those time stamps is later than the DateTime entered for the cached item, ASP.NET unloads that item from the cache.

Click here for all C# Interview Questions

Click here for all ASP.NET Interview Questions

ASP.NET Interview Questions on fragment caching

Click here for all C# Interview Questions

Click here for all ASP.NET Interview Questions

What is fragment caching?
Caching parts of web form is called as fragment caching. Sometimes you want to cache only part of a Web form response. For instance, a Web form might contain many pieces of variable information plus a single large table that almost never changes. In this case, you might place that table in a Web user control and store the response for that control in cache. This technique is called fragment caching.

What are the steps to follow to cache parts of web form?
To cache part of a Web form, follow these steps:
1. Place the controls and content that you want to cache in a Web user control.
2. Set the caching attributes for that Web user control.
3. Create an instance of the Web user control on the Web form.

What is PartialCaching attribute used for?
You can include the PartialCaching attribute in the control�s class declaration to enable fragment caching.

What are the OutputCache directive attributes that apply only to user controls?
Shared
Cache a single response from a user control for use on multiple Web forms. By default, ASP.NET caches a separate response for each Web form that uses a cached user control. This attribute is only available in the .NET Framework version 1.1 or later.

VaryByControl
Cache multiple responses for a single user control based on the value of one or more controls contained in the user control. Can you cache multiple versions of a user control?Yes, You can cache multiple versions of a user control based on the value of controls contained in a user control (VaryByControl) or based on a custom string (VaryByCustom).

If a user control is read from the cache, can you access its members from code?
No, In general, cached controls are used to present data such as queries from a database, rather than as interactive components. However, if you do need to access a cached control from code, you must first check that the control exists. If the control is read from the cache, you can�t access its members from code. Control members are available only when the control is not read from the cache, such as when the control is first instantiated and when it is reloaded after its cache duration has expired.

When caching is set at both the Web form and user control levels, How does the cache settings interact?
The cache location is determined by the Web form setting. Location settings on a user control have no affect.
If the Web form�s cache duration is longer than the user control�s, both the Web form response and the user control response will expire using the Web form setting.
Click here for all C# Interview Questions

Click here for all ASP.NET Interview Questions

What is caching?

Click here for all C# Interview Questions

Click here for all ASP.NET Interview Questions

How do you cache multiple responses from a single Web form?The VaryByParam attribute lets you cache multiple responses from a single Web form based on varying HTTP POST or query string parameters. Setting VaryByParam to None caches only one response for the Web form, regardless of the parameters sent.

You can also cache multiple responses from a single Web form using the VaryByHeaders or VaryByCustom attribute.

The VaryByCustom attribute lets you cache different responses based on a custom string. To use VaryByCustom, override the GetVaryByCustomString method in the Web application�s Global.asax file.Is it possible to cache a web form without using @OutputCache directive?Yes, you can cache a web form using the Response object�s Cache property, which returns an HttpCachePolicy object for the response. The HttpCachePolicy object provides members that are similar to the OutputCache directive�s attributes.Give a simple example to show how to cache a web form without using @OutputCache directive?For example, the following code caches the Web form�s response for 60 seconds:
private void Page_Load(object sender, System.EventArgs e)
{
// Cache this page
DateTimeLabel.Text = System.DateTime.Now.ToString();
// Set OutputCache Duration. Response.Cache.SetExpires(System.DateTime.Now.AddSeconds(60));
// Set OutputCache VaryByParams.
Response.Cache.VaryByParams["None"] = true;
// Set OutputCache Location.
Response.Cache.SetCacheability(HttpCacheability.Public);
}

The preceding code is equivalent to the following OutputCache directive:
@ OutputCache Duration="5" VaryByParam="None" Location="Any"

What is @OutputCache directive�s Location attribute and the HttpCachePolicy object�s SetCacheability property used for?
The @OutputCache directive�s Location attribute and the HttpCachePolicy object�s SetCacheability property determine where Microsoft ASP.NET stores cached responses. By default, ASP.NET caches responses at any available location that accepts cache items - the client, proxy servers, or the host server. In practice, those locations might or might not allow caching, so you can think of the Location/SetCacheability setting as more of a request than a command.What is HttpCachePolicy object�s SetAllowResponseInBrowserHistory method used for?You can override the cache location settings using the HttpCachePolicy object�s SetAllowResponseInBrowserHistory method. Setting that method to True allows the response to be stored in the client�s history folder even if the location setting is None or Server.


Click here for all C# Interview Questions

Click here for all ASP.NET Interview QuestionsHigh-performance Web applications should be designed with caching in mind. Caching is the technique of storing frequently used items in memory so that they can be accessed more quickly. Caching is important to Web applications because each time a Web form is requested, the host server must process the Web form�s HTML and run Web form code to create a response. By caching the response, all that work is bypassed. Instead, the request is served from the reponse already stored in memory.

Caching an item incurs considerable overhead, so it�s important to choose the items to cache wisely. A Web form is a good candidate for caching if it is frequently used and does not contain data that frequently changes. By storing a Web form in memory, you are effectively freezing that form�s server-side content so that changes to that content do not appear until the cache is refreshed.What directive is used to cache a web form?The @OutputCache page directive is used to cache a Web form in the server�s memory.What is the use of duration attribute of @OutputCache page directive?The @OutputCache directive�s Duration attribute controls how long the page is cached. For example if you set the duration attribute to 60 seconds, the Web form is cached for 60 seconds.

The first time any user requests the Web form, the server loads the response in memory and retains that response for 60 seconds. Any subsequent requests during that time receive the cached response.

After the cache duration has expired, the next request for the Web form generates a new response, which is then cached for another 60 seconds. Thus the server processes the Web form once every 60 seconds at most.What are the 2 required attributes of the @OutputCache directive?The @OutputCache directive has two required attributes:
1. Duration
2. VaryByParam.

Interview Questions on ASP.NET Custom Controls

Click here for all C# Interview Questions

Click here for all ASP.NET Interview Questions

What are composite custom controls?
2. User Controls cannot be compiled into an assembly, where as Custom Controls can be compiled into an assembly.

3. User Controls cannot be added to tool box, where as Custom controls can be added to the toolbox.
4. You need to have a copy of user control in every project where you want to use it, where as this is not the case with custom controls. You can install a single copy of the Web custom control in the global assembly cache and share it between applications, which makes maintenance easier.
5. User controls are used for reusing existing user interface elements and code, but are not useful for developing reusable components for multiple web applications.


Click here for all C# Interview Questions

Click here for all ASP.NET Interview Questions
Composite custom controls combine one or more server or HTML controls within a single control class, which can be compiled along with other control classes to create an assembly (.dll) that contains a custom control library. Once created, the custom control library can be loaded into Visual Studio .NET and used in the same way as the standard server and HTML controls.

Composite custom controls are functionally similar to user controls, but they reside in their own assemblies, so you can share the same control among multiple projects without having to copy the control to each project, as you must do with user controls. However, composite controls are somewhat more difficult to create because you can�t draw them visually using the Visual Studio .NET Designer.

What are the steps to follow create and use a custom control in a Web application?
1. Create a solution containing a custom control project.
2. Add a Web application project to the solution, and set it as the startup project. You will use the Web application project to test the custom control during development.
3. Add a project reference from the Web application to the custom control project, and add an HTML @Register directive and control element to use the custom control on a Web form.
4. Create the custom control�s visual interface by adding existing controls to it through the custom control�s CreateChildControls method.
5. Add the properties, methods, and events that the custom control provides.
6. Build and test the custom control.

In general what is the base class for every composite custom control?
System.Web.UI.WebControls.WebControl

Which directive is used to add a custom control to a Web form?
Register directive.

What are the 3 Register directive's attributes?
TagPrefix
This name identifies the group that the user control belongs to. For example, the tag prefix for ASP.NET server controls is �asp�. You use this prefix to create a naming convention to organize your custom controls.
Namespace
This is the project name and namespace within the custom control assembly that contains the controls to register. Microsoft Visual Basic .NET uses the project name as an implicit namespace, so for controls written in Visual Basic .NET, use the project name.
Assembly
This is the name of the assembly (.dll) containing the custom controls. The control assembly must be referenced by the Web application. Referencing the assembly maintains a copy of it in the Web application�s /bin directory.
 
What are the differences between User Controls and Custom Controls?
1. User Controls are easy to create where as Custom Controls are difficult to create.