SharePoint Interview Questions Part-3



Q. How can I raise the trust level for assemblies installed in the BIN directory? Ans. Windows SharePoint Services can use any of the following three options from ASP.NET and the CLR to provide assemblies installed in the BIN directory with sufficient permissions. The following table outlines the implications and requirements for each option.
Option Pros Cons
Increase the trust level for the entire virtual server. For more information, see "Setting the trust level for a virtual server" Easy to implement.
In a development environment, increasing the trust level allows you to test an assembly with increased permissions while allowing you to recompile assemblies directly into the BIN directory without resetting IIS. This option is least secure.
This option affects all assemblies used by the virtual server.

There is no guarantee the destination server has the required trust level. Therefore, Web Parts may not work once installed on the destination server.
Create a custom policy file for your assemblies. For more information, see "How do I create a custom policy file?" Recommended approach.
This option is most secure.

An assembly can operate with a unique policy that meets the minimum permission requirements for the assembly.

By creating a custom security policy, you can ensure the destination server can run your Web Parts. Requires the most configuration of all three options.
Install your assemblies in the GAC Easy to implement.
This grants Full trust to your assembly without affecting the trust level of assemblies installed in the BIN directory. This option is less secure.
Assemblies installed in the GAC are available to all virtual servers and applications on a server running Windows SharePoint Services. This could represent a potential security risk as it potentially grants a higher level of permission to your assembly across a larger scope than necessary

In a development environment, you must reset IIS every time you recompile assemblies.

Licensing issues may arise due to the global availability of your assembly.

Q. When retrieving List items using SharePoint Web Services, how do you specify explicit credentials to be passed to access the list items? Ans. In order to specify explicit credentials with a Web Service, you generally instantiate the web service, and then using the credentials properties of the Web Service object you use the System.Net.NetworkCredential class to specify the username, password, and domain that you wish to pass when making the web service call and operations.
*** Side Question: I got asked when you should state the credentials in code. You must state the credentials you are going to pass to the web service before you call any of the methods of the web service, otherwise the call will fail.

Q. What is CAML, and why would you use it? Ans. CAML stands for Collaborative Application Markup Language. CAML is an XML based language which provides data constructs that build up the SharePoint fields, view, and is used for table definition during site provisioning. CAML is responsible for rending data and the resulting HTML that is output to the user in SharePoint. CAML can be used for a variety of circumstances, overall is used to query, build and customize SharePoint based sites. A general use would be building a CAML query in a SharePoint WebPart in order to retrieve values from a SharePoint list.

Q. What is impersonation, and when would you use impersonation? Ans. Impersonation can basically provide the functionality of executing something in the context of a different identity, for example assigning an account to users with anonymous access. You would use impersonation in order to access resources on behalf of the user with a different account, that normally, that wouldn’t be able to access or execute something.
Q. What is the IDesignTimeHtmlProvider interface, and when can you use it in WebParts? Ans. The IDesignTimeHtmlProvider interface uses the function GetDesignTimeHtml() which can contain your relevant render methods. It was helpful to use in 2003 since it allowed your WebPart to have a preview while a page was edited in FrontPage with the Webpart on it, because the GetDesignTimeHtml() method contains the HTML for the designer to render.
Q. What are WebPart properties, and what are some of the attributes you see when declaring WebPart properties in code? Ans. WebPart properties are just like ASP.NET control properties, they are used to interact with and specify attributes that should be applied to a WebPart by a user. Some of the attributes you see with ASP.NET 2.0 properties are WebDescription, WebDisplayName, Category, Personalizable, and WebBrowsable. Although most of these properties come from the System.Web.UI.WebControls.WebParts class, ones like Category come out of System.ComponentModel namespace.

Q. Why are properties important in WebPart development, and how have you exploited them in past development projects? What must each custom property have? Ans. Properties are important because WebParts allow levels of personalization for each user. WebPart properties make it possible for a user to interact, adjust, and increase overall experience value with the programmatic assets that you develop without having the need to use an external editor or right any code. A very simple example of exploiting a property would be something like allowing the user to change the text on the WebPart design interface so that they can display whatever string of text they desire.
Each custom property that you have must have the appropriate get and set accessor methods.

Q. What are ClassResources? How do you reference and deploy resources with an ASP.NET 2.0 WebPart? Ans. ClassResources are used when inheriting from the SharePoint.WebPart.WebPartPages.WebPart base class, and are defined in the SharePoint solution file as things that should be stored in the wpresources directory on the server. It is a helpful directory to use in order to deploy custom images. In ASP.NET 2.0, typically things such as images are referenced by embedding them as resources within an assembly. The good part about ClassResources is they can help to eliminate recompiles to change small interface adjustments or alterations to external JavaScript files.

Q. What is a SharePoint Solution File? How does it differ from WebPart .cab files in legacy development? What does it contain? Ans. A SharePoint solution file is essentially a .cabinet file with all a developers ustom componets suffixed with a .wsp extension that aids in deployment. The big difference with SharePoint solution files is is that a solution:
allows deployment to all WFE’s in a farm
is highly manageable from the interface allowing deployment, retraction, and versioning
Can package all types of assets like site definitions, feature definitions (and associated components), Webparts, etc.
Can provide Code Access Security provisioning to avoid GAC deployments
Just to name a few things…

Q. What is a .ddf file and what does it have to do with SharePoint Solution creation? Ans. A .ddf file is a data directive file and is used when building the SharePoint solution bundle specifying the source files and their destination locations. The important thing for someone to understand is that the .ddf file will be passed as a parameter to the MAKECAB utility to orchestrate construction of the SharePoint solution file.
Q. What file does a SharePoint solution package use to orchestrate (describe) its packaged contents? Ans. The solution Manifest.XML file.
Q. What deployment mechanism can you use to instigate Code Access Security attributes for your WebParts? Ans. SharePoint solution files can add in order to handle code access security deployment issues. This is done in the element in the SharePoint solution manifest.XML, which makes it easier to get assemblies the appropriate permissions in order to operate in the bin directory of the web application.
Q. What is a SharePoint Feature? What files are used to define a feature? Ans. A SharePoint Feature is a functional component that can be activated and deactivate at various scopes throughout a SharePoint instances, such as at the farm, site collection, web, etc. Features have their own receiver architecture, which allow you to trap events such as when a feature is installing, uninstalling, activated, or deactivated. They are helpful because they allow ease of upgrades and versioning.
The two files that are used to define a feature are the feature.xml and manifest file. The feature XML file defines the actual feature and will make SharePoint aware of the installed feature. The manifest file contains details about the feature such as functionality.
Side Question: I got asked how the introduction of features has changed the concept of site definitions. SharePoint features are important when understanding the architecture of site definitions, since the ONET.XML file has been vastly truncated since it has several feature stapled on it.
Q. What types of SharePoint assets can be deployed with a SharePoint feature? Ans. Features can do a lot. For example, you could deploy
Simple site customizations
Custom site navigation
WebParts
pages
list types
list instances
event handlers
workflows
custom actions

Q. What are event receivers? Ans. Event receivers are classes that inherit from the SpItemEventReciever or SPListEventReciever base class (both of which derive out of the abstract base class SPEventRecieverBase), and provide the option of responding to events as they occur within SharePoint, such as adding an item or deleting an item.
Q. When would you use an event receiver? Ans. Since event receivers respond to events, you could use a receiver for something as simple as canceling an action, such as deleting a document library by using the Cancel property. This would essentially prevent users from deleting any documents if you wanted to maintain retention of stored data.
Q. What base class do event receivers inherit from? Ans. Ev
ent receivers either inherit from the SPListEventReciever base class or the SPItemEventReciever base class, both which derive from the abstract base class SPEventReceiverBase.

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