C #3.0 Study Notes (1) Packaging of using statements and resources

 

1. What is resource?

 

A resource is a class or structure that implements the System. IDisposable interface.

 

Ii. What is the role of the using statement?

 

The Using statement helps reduce potential problems caused by unexpected running errors. It neatly encapsulates the use of resources.

 

3. What is the usage form of the using statement?

 

Using (ResourceType Identifier = Expression)

 

{

 

Statement;

 

}

 

Note: 1. Allocate resources by code in parentheses.

 

2. Statement statements use resources.

 

4. How does the using statement work?

 

Implicitly call try... Finally... Exception handler, which puts the Statement into the try block and puts the Dispose method in the finally block to release resources in time.

 

5. Example of using statements?

 

The Code is as follows:

 

Class Program

 

{

 

Static voidMain (string [] args)

 

{

 

String path = @ "using.txt"; // it is best to indicate the Global Variation of the path string, which can be reused.

 

If (! File. Exists (path) // determines whether the File Exists. If the File does not exist, create the File and upload the characters. If the File does not exist, generate the token in the statement.

 

{

 

Using (TextWriter tw = File. CreateText (path ))

 

{

 

Tw. WriteLine ("using sentence example! ");

 

}

 

}

 

 

Using (TextReader tr = File. OpenText (path ))

 

{

 

String InputString;

 

While (InputString = tr. ReadLine ())! = Null)

 

{

 

Console. WriteLine (InputString );

 

Console. ReadKey ();

 

}

 

}

 

}

 

}

 

Output result:

 

Using sentence example!

 

 

The author's wheat forever.