Brief introduction of C # Boxing and unboxing

The C # language is still more common, and here we introduce C # boxing and unboxing, including aspects such as invoking the Testalias () function.

C # Boxing and unboxing or aliases

Many c#.net books have introduced the int-> Int32 is a boxing process, whereas the reverse is the process of unpacking the box. This is true of many other variable types, such as short <-> int16,long <-> Int64. For the average programmer, it is not necessary to understand this process, because these C # boxing and unboxing actions can be automatically completed, do not need to write code to intervene. But we need to remember the relationships between these types, so we use "aliases" to remember the relationships between them.

C # is a fully object-oriented language, and is more thorough than Java object-oriented-it encapsulates simple data types through default boxing actions into classes. Int32, Int16, Int64 and so on are the corresponding class names, and those familiar, simple and easy to remember names, such as int, short, long, and so on, we can call it the Int32, Int16, Int64 and other types of aliases.

What other classes have "aliases" Besides these three types? Commonly used are the following:

BOOL-> System.Boolean (Boolean, whose value is true or false)

Char-> System.Char (character type, occupies two bytes, representing 1 Unicode characters)

byte-> system.byte (byte type, 1 bytes, 8-bit positive integer, range 0 ~ 255)

SByte-> System.SByte (signed byte, accounting for 1 bytes, representing 8-bit integers, range-128 ~ 127)

ushort-> system.uint16 (unsigned short integer, accounting for 2 bytes, representing 16-bit positive integers, range 0 ~ 65,535)

UINT-> system.uint32 (unsigned integer, accounting for 4 bytes, representing 32-bit positive integers, range 0 ~ 4,294,967,295)

ULONG-> System.UInt64 (unsigned long integer, accounting for 8 bytes, representing 64-bit positive integers, range 0 ~ approximately 10 20 times)

Short-> system.int16 (shorter integer, 2 bytes, 16-bit integer, range-32,768 ~ 32,767)

int-> System.Int32 (integer, 4 bytes, representing 32-bit integers, range-2,147,483,648 to 2,147,483,647)

Long-> System.Int64 (8 bytes, representing 64-bit integers, range approximately-(10 of 19) to 10 of 19)

Float-> system.single (single-precision floating-point type, up to 4 bytes)

Double-> system.double (double-precision floating-point type, up to 8 bytes)

We can do an experiment with the following code:

private　void　TestAlias()　{
//　this.textBox1　是一个文本框，类型为　System.Windows.Forms.TextBox
//　设计中已经将其　Multiline　属性设置为　true
byte　a　=　1;　char　b　=　'a';　short　c　=　1;
int　d　=　2;　long　e　=　3;　uint　f　=　4;　bool　g　=　true;
this.textBox1.Text　=　"";
this.textBox1.AppendText("byte　-
>
　"　+　a.GetType().FullName　+　"\n");
this.textBox1.AppendText("char　-
>
　"　+　b.GetType().FullName　+　"\n");
this.textBox1.AppendText("short　-
>
　"　+　c.GetType().FullName　+　"\n");
this.textBox1.AppendText("int　-
>
　"　+　d.GetType().FullName　+　"\n");
this.textBox1.AppendText("long　-
>
　"　+　e.GetType().FullName　+　"\n");
this.textBox1.AppendText("uint　-
>
　"　+　f.GetType().FullName　+　"\n");
this.textBox1.AppendText("bool　-
>
　"　+　g.GetType().FullName　+　"\n");
}