C# (Sharp) Programming Language Interview Questions And Answers

C# (pronounced C-sharp) is a new object oriented language from Microsoft and is derived from C and C++. It also borrows a lot of concepts from Java too including garbage collection. More at http://msdn.microsoft.com/vstudio/nextgen/technology/csharpintro.asp, http://msdn.microsoft.com/library/default.asp?URL=/library/dotnet/csspec/vclrfcsharpspec_Start.htm and http://msdn.microsoft.com/vstudio/nextgen/technology/csharpdownload.asp

No there is not possible to inline assembly or IL in C# code.

No. The access modifier on a property applies to both its get and set accessors. What you need to do if you want them to be different is make the property read-only (by only providing a get accessor) and create a private/internal set method that is separate from the property.

No. Static indexers are not in C# (Sharp)

Yes. The code in the finally always runs. If you return out of the try block, or even if you do a goto out of the try, the finally block always runs:
using System;
<pre>
class main
{
public static void Main()
{
try
{
Console.WriteLine("In Try block");
return;
}
finally
{
Console.WriteLine("In Finally block");
}
}
}
</pre>
Both In Try block and In Finally block will be displayed. Whether the return is in the try block or after the try-finally block, performance is not affected either way. The compiler treats it as if the return were outside the try block anyway. If it’s a return without an expression (as it is above), the IL emitted is identical whether the return is inside or outside of the try. If the return has an expression, there’s an extra store/load of the value of the expression (since it has to be computed within the try block).

You should declare the variable as an int, but when you pass it in you must specify it as ‘out’, like the following: int i; foo(out i); where foo is declared as follows:
[return-type] foo(out int o) { }

In the past, you had to call .ToString() on the strings when using the == or != operators to compare the strings’ values. That will still work, but the C# compiler now automatically compares the values instead of the references when the == or != operators are used on string types. If you actually do want to compare references, it can be done as follows: if ((object) str1 == (object) str2) { } Here’s an example showing how string compares work:
using System;
<pre>
public class StringTest
{
public static void Main(string[] args)
{
Object nullObj = null; Object realObj = new StringTest();
int i = 10;
Console.WriteLine("Null Object is [" + nullObj + "] "
+ "Real Object is [" + realObj + "] "
+ "i is [" + i + "] ");
// Show string equality operators
string str1 = "foo";
string str2 = "bar";
string str3 = "bar";
Console.WriteLine("{0} == {1} ? {2}", str1, str2, str1 == str2 );
Console.WriteLine("{0} == {1} ? {2}", str2, str3, str2 == str3 );
}
}
</pre>
Output:

Null Object is []
Real Object is [StringTest]
i is [10]
foo == bar ? False
bar == bar ? True

Global attributes must appear after any top-level using clauses and before the first type or namespace declarations. An example of this is as follows:
using System;
[assembly : MyAttributeClass] class X {}
Note that in an IDE-created project, by convention, these attributes are placed in AssemblyInfo.cs.

[Obsolete] public int Foo() {...}
or
[Obsolete("This is a message describing why this method is obsolete")] public int Foo() {...}
Note: The O in Obsolete is always capitalized.

You want the lock statement, which is the same as Monitor Enter/Exit:

lock(obj) { // code }

translates to

try {
CriticalSection.Enter(obj);
// code
}
finally
{
CriticalSection.Exit(obj);
}

Here’s a quick example of the DllImport attribute in action:

using System.Runtime.InteropServices;
class C
{
[DllImport("user32.dll")]
public static extern int MessageBoxA
(int h, string m, string c, int type);
public static int Main()
{
return MessageBoxA(0, "Hello World!", "Caption", 0);
}
}

This example shows the minimum requirements for declaring a C# method that is implemented in a native DLL. The method C.MessageBoxA() is declared with the static and external modifiers, and has the DllImport attribute, which tells the compiler that the implementation comes from the user32.dll, using the default name of MessageBoxA. For more information, look at the Platform Invoke tutorial in the documentation.

You must use the Missing class and pass Missing.Value (in System.Reflection) for any values that have optional parameters.

1. System.Int16
2. System.Int32
3. System.Int64
4. System.Int128

1. string s = #.n Test string.;
2. string s = ..n Test string.;
3. string s = @.n Test string.;
4. string s = .n Test string.;

1. int[,] myArray;
2. int[][] myArray;
3. int[2] myArray;
4. System.Array[2] myArray;

1. Classes that are both in the same assembly and derived from the declaring class.
2. Only methods that are in the same class as the method in question.
3. Internal methods can be only be called using reflection.
4. Classes within the same assembly, and classes derived from the declaring class.

1. Encapsulating an object in a value type.
2. Encapsulating a copy of an object in a value type.
3. Encapsulating a value type in an object.
4. Encapsulating a copy of a value type in an object.

1. /text
2. /doc
3. /xml
4. /help

When you write a multilingual or multi-cultural application in .NET, and want to distribute the core application separately from the localized modules, the localized assemblies that modify the core application are called satellite assemblies.

C# delegate is a:
1. A strongly typed function pointer.
2. A light weight thread or process that can call a single method.
3. A reference to an object in a different process.
4. An inter-process message channel.

1. The runtime checks to see that only one version of an assembly is on the machine at any one time.
2. .NET allows assemblies to specify the name AND the version of any assemblies they need to run.
3. The compiler offers compile time checking for backward compatibility.
4. It doesn't.

<pre> public class A {
private A instance;
private A() {
}
public
static A Instance {
get
{
if ( A == null )
A = new A();
return instance;
}
}
}
</pre>
1. Factory
2. Abstract Factory
3. Singleton
4. Builder

1. TestAttribute
2. TestClassAttribute
3. TestFixtureAttribute
4. NUnitTestClassAttribute

1. A DataSet can be synchronised with the database.
2. A DataSet can be synchronised with a RecordSet.
3. A DataSet can be converted to XML.
4. You can infer the schema from a DataSet.

1. The conversion of one type of object to another in C#.
2. The runtime resolution of method calls in C#.
3. The exposition of data in C#.
4. The separation of interface and implementation in C#.