Important .Net Questions and Answers - IV

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Important .Net Questions and Answers - IV

What is nmake tool?

The Nmake tool (Nmake.exe) is a 32-bit tool that you use to build projects based on commands contained in a .mak file.
usage : nmake -a all

What are Namespaces?

The namespace keyword is used to declare a scope. This namespace scope lets you organize code and gives you a way to create globally-unique types. Even if you do not explicitly declare one, a default namespace is created.

This unnamed namespace, sometimes called the global namespace, is present in every file. Any identifier in the global namespace is available for use in a named namespace. Namespaces implicitly have public access and this is not modifiable.

C++ & C# differences
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87. If you want to write your own dot net language, what steps you will u take care?
88. What is custom events? How to create it?
89. how dot net compiled code will become platform independent?
90. without modifying source code if we compile again, will it be generated MSIL again?
91. Describe the difference between inline and code behind - which is best in a loosely coupled solution?
92. What is the difference between CONST and READONLY?
93. What is the difference between ref & out parameters?
What is the difference between arrays and Arraylist?
94. What are indexers?
95. How to create events for a control?
96. Explain about SOAP
97. Practical Example of Passing an Events to delegates
98. How can you read 3rd line from a text file?
99. What is Asynchronous call and how it can be implemented using delegates?
100. What is the difference between Array and LinkedList?

101. What is Jagged Arrays?

A jagged array is an array whose elements are arrays. The elements of a jagged array can be of different dimensions and sizes. A jagged array is sometimes called an "array-of-arrays."

(COM)

Interop Services?

The common language runtime provides two mechanisms for interoperating with unmanaged code:

Platform invoke, which enables managed code to call functions exported from an unmanaged library.
COM interop, which enables managed code to interact with COM objects through interfaces.

Both platform invoke and COM interop use interop marshaling to accurately move method arguments between caller and callee and back, if required.

How does u handle this COM components developed in other programming languages in .NET?

What is RCW (Runtime Callable Wrappers)?

The common language runtime exposes COM objects through a proxy called the runtime callable wrapper (RCW). Although the RCW appears to be an ordinary object to .NET clients, its primary function is to marshal calls between a .NET client and a COM object.

What is CCW (COM Callable Wrapper)

A proxy object generated by the common language runtime so that existing COM applications can use managed classes, including .NET Framework classes, transparently.

How CCW and RCW is working?

How will you register com+ services?

The .NET Framework SDK provides the .NET Framework Services Installation Tool (Regsvcs.exe - a command-line tool) to manually register an assembly containing serviced components. You can also access these registration features programmatically with the System.EnterpriseServicesRegistrationHelper class by creating an instance of class RegistrationHelper and using the method InstallAssembly

What is use of ContextUtil class?

ContextUtil is the preferred class to use for obtaining COM+ context information.

What is the new three features of COM+ services, which are not there in COM (MTS)?
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Is the COM architecture same as .Net architecture? What is the difference between them?
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Can we copy a COM dll to GAC folder?
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What is Pinvoke?

Platform invoke is a service that enables managed code to call unmanaged functions implemented in dynamic-link libraries (DLLs), such as those in the Win32 API. It locates and invokes an exported function and marshals its arguments (integers, strings, arrays, structures, and so on) across the interoperation boundary as needed.

113. Is it true that COM objects no longer need to be registered on the server?

Answer: Yes and No. Legacy COM objects still need to be registered on the server before they can be used. COM developed using the new .NET Framework will not need to be registered. Developers will be able to auto-register these objects just by placing them in the 'bin' folder of the application.

114. Can .NET Framework components use the features of Component Services?

Answer: Yes, you can use the features and functions of Component Services from a .NET Framework component.

(OOPS)

115. What are the OOPS concepts?

1) Encapsulation: It is the mechanism that binds together code and data in manipulates, and keeps both safe from outside interference and misuse. In short it isolates a particular code and data from all other codes and data. A well-defined interface controls the access to that particular code and data.

2) Inheritance: It is the process by which one object acquires the properties of another object. This supports the hierarchical classification. Without the use of hierarchies, each object would need to define all its characteristics explicitly. However, by use of inheritance, an object need only define those qualities that make it unique within its class. It can inherit its general attributes from its parent. A new sub-class inherits all of the attributes of all of its ancestors.

3) Polymorphism: It is a feature that allows one interface to be used for general class of actions. The specific action is determined by the exact nature of the situation. In general polymorphism means "one interface, multiple methods", This means that it is possible to design a generic interface to a group of related activities.

This helps reduce complexity by allowing the same interface to be used to specify a general class of action. It is the compiler's job to select the specific action (that is, method) as it applies to each situation.

116. What is the difference between a Struct and a Class?

The struct type is suitable for representing lightweight objects such as Point, Rectangle, and Color. Although it is possible to represent a point as a class, a struct is more efficient in some scenarios. For example, if you declare an array of 1000 Point objects, you will allocate additional memory for referencing each object. In this case, the struct is less expensive.

When you create a struct object using the new operator, it gets created and the appropriate constructor is called. Unlike classes, structs can be instantiated without using the new operator. If you do not use new, the fields will remain unassigned and the object cannot be used until all of the fields are initialized.

It is an error to declare a default (parameterless) constructor for a struct. A default constructor is always provided to initialize the struct members to their default values.

It is an error to initialize an instance field in a struct.

There is no inheritance for structs as there is for classes. A struct cannot inherit from another struct or class, and it cannot be the base of a class. Structs, however, inherit from the base class Object. A struct can implement interfaces, and it does that exactly as classes do.

A struct is a value type, while a class is a reference type.

117. Value type & reference types difference? Example from .NET. Integer & struct are value types or reference types in .NET?

Most programming languages provide built-in data types, such as integers and floating-point numbers, that are copied when they are passed as arguments (that is, they are passed by value). In the .NET Framework, these are called value types. The runtime supports two kinds of value types:

Built-in value types

The .NET Framework defines built-in value types, such as System.Int32 and System.Boolean, which correspond and are identical to primitive data types used by programming languages.

User-defined value types

Your language will provide ways to define your own value types, which derive from System.ValueType. If you want to define a type representing a value that is small, such as a complex number (using two floating-point numbers), you might choose to define it as a value type because you can pass the value type efficiently by value. If the type you are defining would be more efficiently passed by reference, you should define it as a class instead.

Variables of reference types, referred to as objects, store references to the actual data. This following are the reference types:
class
interface
delegate

This following are the built-in reference types:

object
string