Archive for the ‘MCPD’ category

Unboxing is the inverse of boxing. Unboxing is used to explicitly convert reference type to value type. An unboxing operation consists of the following two actions:

• Checking the object instance to make sure it is a boxed value of the given value type.
• Copying the value from the instance into the value type variable.

The following statements will demonstrate an unboxing operation:

int test=457;                 //A value type
object obj=test;            //A reference type
int result=(int) obj;      //Unboxing

The unboxing conversion to a given value will succeed at runtime. This is possible only if the source argument is a reference to an object that is compatible and not null. Otherwise, an InvalidCastException is thrown.

The steps to move a file from one location to another location are as follows:

1. Implement the System.IO namespace as follows.
   
   using System.IO;
   
2. Enter the source path of the file that is to be moved and the destination path where the file is to be moved.
   
   string source=@” d: emp est.txt “;
   string destination=@” d:Myapp emp1 est.txt “;
   
3. Check whether the source file exists. If it does not exist, create it.
   
   If(!File.Exists(source)
   {
   //This block is executed only when source file does not exist
      FileStream fs=File.Create(source);
   }
   
4. Ensure that the target does not exist.
   
   If(File.Exists(destination)
   File.Delete(destination);
   
5. Move the file.
   
   File.Move(source, destination);
   
6. Close the FileStream class, if used.
   
   fs.Close();

The steps to use the UTF8Encoding class to encode and decode a text data are as follows:

1. Implement the following namespace:

   using System.Text;

2. Create a UTF8Encoding class object as follows:

   UTF8Encoding utf8 = new UTF8Encoding();
   

3. Create a string object to store input text as follows:

   String unicodeString =”This unicode string contains two characters with codes outside an 8-bit code range,Pi (u03a0) and Sigma (u03a3)”;

4. Encode the given text in the following manner:

   Byte[] encodedText = utf8.GetBytes(unicodeString);

5. Display the encoded text as follows:

   foreach (Byte bt in encodedText)
   Console.Write(“[{0}]“, bt);
   

6. Decode the encoded text as follows:

   String decodeStr = utf8.GetString(encodedText);
   

7. Display the decoded text as follows:

   Console.WriteLine(decodedStr);