Three generic sorting methods

Third of the three generic sorting methods: Use the Sort sorting method of the IComparer subclass to add to favorites
There are three methods for sorting generics:
1. List <T>. Sort (), which can only be used when the set element implements the IComparable generic interface
2. List <T>. sort (Comparison <T>), Comparison <T> is a method delegate. It has two parameters T and returns the int type. You can flexibly specify how to Sort them, however, you must manually specify how to sort the codes;
3. List <T>. sort (IComparer <T>) uses classes that implement the IComparer <T> interface to Sort the set. You can flexibly specify how to Sort the set, but you need to define the class sorting method in advance.

The third method is described here:
First, define a class as the element of the set.
Using System;
Using System. Collections. Generic;
/// <Summary>
/// Student
/// </Summary>
Public class Student
{
Private string name;
// Name
Public string Name
{
Get {return name ;}
Set {name = value ;}
}
Private int age;
// Age
Public int Age
{
Get {return age ;}
Set {age = value ;}
}

Private string grade;
// Grade
Public string Grade
{
Get {return grade ;}
Set {grade = value ;}
}
// Constructor
Public Student (string name, int age, string grade)
{
This. name = name;
This. age = age;
This. grade = grade;
}
Public override string ToString ()
{
Return this. name + "," + this. age. ToString () + "," + this. grade;
}
}

Next, define a class for comparison to implement the IComparer <T> generic interface:
Public class StudentComparer: IComparer <Student>
{
Public enum CompareType
{
Name,
Age,
Grade
}

Private CompareType type;
// Constructor, based on the value of type, determines which field to sort
Public StudentComparer (CompareType type)
{
This. type = type;
}

# Region IComparer <Student> Member
Public int Compare (Student x, Student y)
{
Switch (this. type)
{
Case CompareType. Name:
Return x. Name. CompareTo (y. Name );
Case CompareType. Age:
Return x. Age. CompareTo (y. Age );
Default: // case CompareType. Grade:
Return x. Grade. CompareTo (y. Grade );
}
}

# Endregion
}

The sorting is started as follows:
Using System;
Using System. Collections. Generic;
Public class test
{
Public static void Main ()
{
List <Student> arr = new List <Student> ();
Arr. Add (new Student ("James", 7, ""));
Arr. Add (new Student ("Li Si", 11, ""));
Arr. Add (new Student ("Wang Wu", 21, "First Grade "));
Arr. Add (new Student ("Chen Liu", 8, "Grade 3 "));
Arr. Add (new Student ("Liu Qi", 15, ""));

// Call the Sort method to Sort by grade
Arr. Sort (new StudentComparer (StudentComparer. CompareType. Grade ));
// Cyclically display the elements in the Set
Foreach (Student item in arr)
Console. WriteLine (item. ToString ());

// Call the Sort method to Sort by name
Arr. Sort (new StudentComparer (StudentComparer. CompareType. Name ));
// Cyclically display the elements in the Set
Foreach (Student item in arr)
Console. WriteLine (item. ToString ());
}
}

The third method is described here:
First, define a class as the element of the set.
Using System;
Using System. Collections. Generic;
/// <Summary>
/// Student
/// </Summary>
Public class Student
{
Private string name;
// Name
Public string Name
{
Get {return name ;}
Set {name = value ;}
}
Private int age;
// Age
Public int Age
{
Get {return age ;}
Set {age = value ;}
}

Private string grade;
// Grade
Public string Grade
{
Get {return grade ;}
Set {grade = value ;}
}
// Constructor
Public Student (string name, int age, string grade)
{
This. name = name;
This. age = age;
This. grade = grade;
}
Public override string ToString ()
{
Return this. name + "," + this. age. ToString () + "," + this. grade;
}
}

Next, define a class for comparison to implement the IComparer <T> generic interface:
Public class StudentComparer: IComparer <Student>
{
Public enum CompareType
{
Name,
Age,
Grade
}

Private CompareType type;
// Constructor, based on the value of type, determines which field to sort
Public StudentComparer (CompareType type)
{
This. type = type;
}

# Region IComparer <Student> Member
Public int Compare (Student x, Student y)
{
Switch (this. type)
{
Case CompareType. Name:
Return x. Name. CompareTo (y. Name );
Case CompareType. Age:
Return x. Age. CompareTo (y. Age );
Default: // case CompareType. Grade:
Return x. Grade. CompareTo (y. Grade );
}
}

# Endregion
}

The sorting is started as follows:
Using System;
Using System. Collections. Generic;
Public class test
{
Public static void Main ()
{
List <Student> arr = new List <Student> ();
Arr. Add (new Student ("James", 7, ""));
Arr. Add (new Student ("Li Si", 11, ""));
Arr. Add (new Student ("Wang Wu", 21, "First Grade "));
Arr. Add (new Student ("Chen Liu", 8, "Grade 3 "));
Arr. Add (new Student ("Liu Qi", 15, ""));

// Call the Sort method to Sort by grade
Arr. Sort (new StudentComparer (StudentComparer. CompareType. Grade ));
// Cyclically display the elements in the Set
Foreach (Student item in arr)
Console. WriteLine (item. ToString ());

// Call the Sort method to Sort by name
Arr. Sort (new StudentComparer (StudentComparer. CompareType. Name ));
// Cyclically display the elements in the Set
Foreach (Student item in arr)
Console. WriteLine (item. ToString ());
}
}