What is the C Using block and why should I use it

Question

What is the purpose of the Using block in C   How is it different from a local variable

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using  B a   new B         DoSomethingWith a       is equivalent to  B a   new B    try     DoSomethingWith a     finally        IDisposable a  Dispose

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using  B a   new B         DoSomethingWith a       is equivalent to  B a   new B    try     DoSomethingWith a     finally        IDisposable a  Dispose

User · Answer

It is really just some syntatic sugar that does not require you to explicity call Dispose on members that implement IDisposable

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The using statement obtains one or more resources  executes a statement  and then disposes of the resource

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The using statement obtains one or more resources  executes a statement  and then disposes of the resource

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The using statement is used to work with an object in C  that implements the IDisposable interface    The IDisposable interface has one public method called Dispose that is used to dispose of the object  When we use the using statement  we don t need to explicitly dispose of the object in the code  the using statement takes care of it   using  SqlConnection conn   new SqlConnection           When we use the above block  internally the code is generated like this   SqlConnection conn   new SqlConnection    try      finally          calls the dispose method of the conn object     For more details read  Understanding the  using  statement in C

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From MSDN      C   through the  NET Framework common   language runtime  CLR   automatically   releases the memory used to store   objects that are no longer required    The release of memory is   non-deterministic  memory is released   whenever the CLR decides to perform   garbage collection  However  it is   usually best to release limited   resources such as file handles and   network connections as quickly as   possible        The using statement allows the   programmer to specify when objects   that use resources should release   them  The object provided to the using   statement must implement the   IDisposable interface  This interface   provides the Dispose method  which   should release the object s resources    In other words  the using statement tells  NET to release the object specified in the using block once it is no longer needed

User · Answer

It is really just some syntatic sugar that does not require you to explicity call Dispose on members that implement IDisposable

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Also take note that the object instantiated via using is read-only within the using block   Refer to the official C  reference here

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using  B a   new B         DoSomethingWith a       is equivalent to  B a   new B    try     DoSomethingWith a     finally        IDisposable a  Dispose

User · Answer

Using calls Dispose   after the using-block is left  even if the code throws an exception   So you usually use using for classes that require cleaning up after them  like IO   So  this using block   using  MyClass mine   new MyClass        mine Action        would do the same as   MyClass mine   new MyClass    try     mine Action      finally     if  mine    null      mine Dispose        Using using is way shorter and easier to read

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If the type implements IDisposable  it automatically disposes that type  Given  public class SomeDisposableType   IDisposable         implmentation details       These are equivalent  SomeDisposableType t   new SomeDisposableType    try       OperateOnType t     finally       if  t    null              IDisposable t  Dispose               using  SomeDisposableType u   new SomeDisposableType          OperateOnType u      The second is easier to read and maintain

User · Answer

Using calls Dispose   after the using-block is left  even if the code throws an exception   So you usually use using for classes that require cleaning up after them  like IO   So  this using block   using  MyClass mine   new MyClass        mine Action        would do the same as   MyClass mine   new MyClass    try     mine Action      finally     if  mine    null      mine Dispose        Using using is way shorter and easier to read

User · Answer

Using calls Dispose   after the using-block is left  even if the code throws an exception   So you usually use using for classes that require cleaning up after them  like IO   So  this using block   using  MyClass mine   new MyClass        mine Action        would do the same as   MyClass mine   new MyClass    try     mine Action      finally     if  mine    null      mine Dispose        Using using is way shorter and easier to read

User · Answer

It is really just some syntatic sugar that does not require you to explicity call Dispose on members that implement IDisposable

User · Answer

If the type implements IDisposable  it automatically disposes that type  Given  public class SomeDisposableType   IDisposable         implmentation details       These are equivalent  SomeDisposableType t   new SomeDisposableType    try       OperateOnType t     finally       if  t    null              IDisposable t  Dispose               using  SomeDisposableType u   new SomeDisposableType          OperateOnType u      The second is easier to read and maintain

User · Answer

The using statement is used to work with an object in C  that implements the IDisposable interface    The IDisposable interface has one public method called Dispose that is used to dispose of the object  When we use the using statement  we don t need to explicitly dispose of the object in the code  the using statement takes care of it   using  SqlConnection conn   new SqlConnection           When we use the above block  internally the code is generated like this   SqlConnection conn   new SqlConnection    try      finally          calls the dispose method of the conn object     For more details read  Understanding the  using  statement in C

User · Answer

From MSDN      C   through the  NET Framework common   language runtime  CLR   automatically   releases the memory used to store   objects that are no longer required    The release of memory is   non-deterministic  memory is released   whenever the CLR decides to perform   garbage collection  However  it is   usually best to release limited   resources such as file handles and   network connections as quickly as   possible        The using statement allows the   programmer to specify when objects   that use resources should release   them  The object provided to the using   statement must implement the   IDisposable interface  This interface   provides the Dispose method  which   should release the object s resources    In other words  the using statement tells  NET to release the object specified in the using block once it is no longer needed

User · Answer

If the type implements IDisposable  it automatically disposes that type  Given  public class SomeDisposableType   IDisposable         implmentation details       These are equivalent  SomeDisposableType t   new SomeDisposableType    try       OperateOnType t     finally       if  t    null              IDisposable t  Dispose               using  SomeDisposableType u   new SomeDisposableType          OperateOnType u      The second is easier to read and maintain

User · Answer

From MSDN      C   through the  NET Framework common   language runtime  CLR   automatically   releases the memory used to store   objects that are no longer required    The release of memory is   non-deterministic  memory is released   whenever the CLR decides to perform   garbage collection  However  it is   usually best to release limited   resources such as file handles and   network connections as quickly as   possible        The using statement allows the   programmer to specify when objects   that use resources should release   them  The object provided to the using   statement must implement the   IDisposable interface  This interface   provides the Dispose method  which   should release the object s resources    In other words  the using statement tells  NET to release the object specified in the using block once it is no longer needed

User · Answer

If the type implements IDisposable  it automatically disposes that type  Given  public class SomeDisposableType   IDisposable         implmentation details       These are equivalent  SomeDisposableType t   new SomeDisposableType    try       OperateOnType t     finally       if  t    null              IDisposable t  Dispose               using  SomeDisposableType u   new SomeDisposableType          OperateOnType u      The second is easier to read and maintain

User · Answer

Placing code in a using block ensures that the objects are disposed  though not necessarily collected  as soon as control leaves the block

User · Answer

From MSDN      C   through the  NET Framework common   language runtime  CLR   automatically   releases the memory used to store   objects that are no longer required    The release of memory is   non-deterministic  memory is released   whenever the CLR decides to perform   garbage collection  However  it is   usually best to release limited   resources such as file handles and   network connections as quickly as   possible        The using statement allows the   programmer to specify when objects   that use resources should release   them  The object provided to the using   statement must implement the   IDisposable interface  This interface   provides the Dispose method  which   should release the object s resources    In other words  the using statement tells  NET to release the object specified in the using block once it is no longer needed

User · Answer

Placing code in a using block ensures that the objects are disposed  though not necessarily collected  as soon as control leaves the block

User · Answer

It is really just some syntatic sugar that does not require you to explicity call Dispose on members that implement IDisposable

User · Answer

Using calls Dispose   after the using-block is left  even if the code throws an exception   So you usually use using for classes that require cleaning up after them  like IO   So  this using block   using  MyClass mine   new MyClass        mine Action        would do the same as   MyClass mine   new MyClass    try     mine Action      finally     if  mine    null      mine Dispose        Using using is way shorter and easier to read

User · Answer

Also take note that the object instantiated via using is read-only within the using block   Refer to the official C  reference here

User · Answer

using  B a   new B         DoSomethingWith a       is equivalent to  B a   new B    try     DoSomethingWith a     finally        IDisposable a  Dispose

User · Answer

Placing code in a using block ensures that the objects are disposed  though not necessarily collected  as soon as control leaves the block

User · Answer

Placing code in a using block ensures that the objects are disposed  though not necessarily collected  as soon as control leaves the block

[c#] What is the C# Using block and why should I use it?

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