C# FAQ

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The C# FAQ—Frequently Asked Questions—provides answers to the most common questions asked of our C# and .NET community.

Contents 1 C# Frequently Asked Questions (FAQ) 1.1 The C# Language FAQ 1.2 C# and .NET FAQ 1.3 C# and C FAQ 1.4 C# and C++ FAQ 1.5 C# and Java Language FAQ 1.6 C# and Visual Basic (VB) FAQ 1.7 C# and Visual J++ FAQ 1.8 C# and ADO.NET FAQ 1.9 C# and Windows Forms FAQ 2 See also

C# Frequently Asked Questions (FAQ)

The C# Language FAQ

• Am I missing an assembly reference?
• Are C# constructors inherited?
• Are C# parameters passed by reference or by value ?
• Can a property have different get and set access?
• Can const and static be used together?
• Can I directly call a native function exported from a DLL?
• Do unused references to external assemblies lead to code bloat?
• Does C# have its own class library?
• Does C# have macros or a preprocessor?
• Does C# support custom exceptions?
• Does C# support jagged arrays?
• Does C# support variable method arguments (vararg)?
• How call overloaded operators from non-supporting languages?
• How can I force garbage collection?
• How can I output simple debugging messages?
• How can one constructor call another?
• How check the object type at runtime?
• How can type name clashes be resolved?
• How do destructors work in C#?
• How do I declare an out variable?
• How do I get DllImport to work?
• How do I make a C# DLL?
• How do I use trace and assert?
• How get the type name at runtime?
• How keep a local variable in scope across a try-catch block?
• How make sure C# classes will interoperate with other .NET languages?
• How perform a case insensitive string comparison?
• How process command line arguments?
• How specify a C# literal type?
• How subscribe to events exposed by remoted objects?
• How to obtain type information on the fly using typeof?
• How use an alias for a class or namespace?
• How would I create a Delegate or MulticastDelegate?
• Is there C# support for C-type macros?
• Is there C# support for templates?
• What are the C# character escape sequences (\)?
• What does at sign (@) identifier mean?
• What does "Object reference not set to an instance of an object" mean?
• What is a namespace?
• What is a type alias?
• What is C#?
• What is a C# response file?
• What is a verbatim string literal (@)?
• What is the C# Language Specification?
• What is the #define preprocessor directive?
• What is the difference between const and static readonly?
• What is the difference between delegate and event?
• What is the difference between GetType() and typeof?
• What is the difference between new and override?
• What is the difference between the out and ref parameter modifiers?
• What is the difference between string and System.String?
• What is the difference between using a cast and the as operator?
• What is the syntax for calling an overloaded constructor from within a constructor?
• What is the use of the C# compiler's /target: command line option?
• What is the Windows Class Viewer?
• What software is needed to develop C# applications?
• When should an exception be thrown?
• When should Equals and == be used?
• Will Console.WriteLine() stop printing upon encountering a NULL character in a string?
• Why add a using statement and a reference?
• Why are hashtable lookups so slow with struct keys?
• Why do I get a syntax error when I try to declare a variable named checked?
• Why does C# not support checked exceptions?
• Why does my Windows application open a console window each time it is run?
• Why doesn't the C# switch statement work like I expect it to?
• Why doesn't a Windows Form project use visual styles in XP?
• Why get an error (CS1006) when declaring a method without a return type?
• Why must struct constructors have at least one argument?

C# and .NET FAQ

• What is .NET?
• Must the framework be installed to run .NET applications?
• Does .NET run only on Windows?
• What do all the .NET acronyms mean?
• Are .NET generics like C++ templates?
• How enforce coding guidelines for custom .NET assemblies?
• Is there a .NET equivalent to regsvr32?
• How call a method using a name string?
• Are there free .NET decompilers?
• How good are .NET decompilers?
• How protect .NET code from reverse engineering?
• How protect my code against decompilation?
• What about .NET decompilers that allow code to be submitted from browsers?
• What does a .NET decompiler do?
• How start another program from .NET?
• How ensure that only one instance of an application will run?
• How to read files with accented characters?
• How get assembly attributes at runtime?
• Why does .NET make arithmetic errors?
• How display int as a binary number, a string of 0s and 1s?
• Should calling Initialize() on a reference type array fill it with objects?
• What compression and zipping capabilities does .NET have?
• How convert a string type to an int type?
• What is the difference between Convert.ToInt32(string) and Int32.Parse(string)?
• How create an instance of a type using only its name?
• What is the easiest way to fetch a Web page in .NET?

C# and C FAQ

• How can I declare inout arguments in C#?

C# and C++ FAQ

• Are .NET generics like C++ templates?
• Are all C# methods virtual?
• Are constructors the same in C++ and C#?
• Are destructors the same in C++ and C#?
• Are references the same in C++ and C#?
• Are standard types the same in C++ and C#?
• Are structs the same in C++ and C#?
• Does C# check array bounds? (array bounds checking)
• Does C# have global methods?
• Does C# have multiple inheritance like C++?
• Does C# replace C++?
• How call a virtual method from a constructor or destructor?
• How declare a pure virtual function in C#?
• How enforce constructor correctness in C#?
• How make a C# destructor virtual?
• Is a C++ abstract class like a C# interface?
• Is typedef available in C#?
• What are the differences between C# and C++ inheritance syntax?

C# and Java Language FAQ

• Are C# classes allocated on the heap?
• Are C# strings immutable?
• Does C# have a throws clause?
• Does C# support boxing?
• Does C# support final classes?
• Does C# support jagged arrays?
• Does C# support static initialization blocks?
• How do Java and C# objects compare?
• What are the differences between C# and Java access modifiers?
• What are the differences between C# and Java constant declarations?
• What are the differences between C# and Java constructors?
• What are the differences between C# and Java exceptions?
• What are the differences between C# and Java garbage collection?
• What are the differences between C# and Java generics?
• What are the differences between C# and Java inheritance syntax?
• What are the differences between C# and Java keywords?
• What are the differences between C# and Java Main methods?
• What are the differences between C# and Java member initialization?
• What are the differences between C# and Java primitive types?
• What are the differences between C# and Java reflection?
• What are the differences between C# and Java runtimes?
• What are the differences between C# and Java variable length parameter lists?
• What are the differences between C# and Java virtual machines?
• What are the differences between C# finalizers and Java destructors?
• What is the difference between C# and Java array declarations?
• What is the difference between C# and Java constructor chaining?
• What is the difference between C# and Java enumerations (enum)?
• What is the difference between C# and Java foreach loops?
• What is the difference between C# and Java threads?
• What is the difference between C# lock and Java synchronized?
• What is the difference between C# using and Java package?
• What is the difference between calling base class constructors in C# and Java?
• What is the difference between metadata annotations in C# and Java?
• What is the difference between nested classes in C# and Java?

C# and Visual Basic (VB) FAQ

• Does C# have with from Visual Basic (VB)?
• How do I convert or upgrade my Visual Basic (VB) application to a C# application?
• How get the rightmost part of a string?
• What is the C# equivalent of addressof in VB?
• What is the C# equivalent of Me in VB?
• What is the C# equivalent of MyBase in VB?
• What is the C# equivalent of MyClass in VB?
• What is the C# equivalent of Nothing in VB?
• Why choose C# over Visual Basic (VB)?

C# and Visual J++ FAQ

• How can I port synchronized functions from Visual J++ to C#?
• What is the C# equivalent of the J++ instanceof operator?

C# and ADO.NET FAQ

• How escape text in SQL statements?
• How express dates and times in SQL statements?
• What is the difference between Close and Dispose?

C# and Windows Forms FAQ

• How monitor changes to Clipboard contents?
• How pass parameters from one form to another?
• How set the background of an MDI container window?

See also

• C# Online.NET Forums - ask and answer questions by community members.