C#泛型之List操作示例

private void button1_Click(object sender, EventArgs e)

{

label1.Text = "";
/*

ArrayList AL = new ArrayList(3);

TestData temp = new TestData(1);

AL.Add(temp);

AL.Add(new TestData(2));

AL.Add(new TestData(3));

foreach (TestData item in AL)

{

label1.Text += item.Val.ToString() + " ";

item.Val += 1;

}

foreach (TestData item in AL)

{

label1.Text += item.Val.ToString() + " ";

}

*/

List<Racer> racers;

List<Racer> racers2;

FindRacer finder;

//--------------------------------------------------------------------------------

//生成泛型对象

racers = new List<Racer>();

racers.Add(new Racer("M J", "L"));

racers.Add(new Racer("AD3 R", "OK3"));

racers.Add(new Racer("M2 O", "L2"));

racers.Add(new Racer("AD2 Q", "OK2"));

racers.Add(new Racer("M1 W", "L"));

racers.Add(new Racer("AD4 A", "OK4"));

racers.Add(new Racer("AD1 L", "OK1"));

//跌代显示泛型对象所有元素

label1.Text += "\n跌代显示泛型对象所有元素\n";

foreach (Racer item in racers)

{

label1.Text += item.ToString() + " ";

}

//--------------------------------------------------------------------------------

/*

List<T>查找对象:Preadcate<T>是一个委托,它引用一个谓词方法.

public T Find<Predicate<T> match);

public List<T> FindAll<Predicate<T> match);

*/

//委托查找所有满足条件的元素

label1.Text += "\nFindAll(Car==\"L\")\n";

finder = new FindRacer("L");

foreach(Racer item in racers.FindAll(new Predicate<Racer>(finder.DrivingCarPredicate)))

{

label1.Text += item.ToString() + " ";

}

label1.Text += "\nFindAll(Car==\"L\")将结果赋给其它泛型对象\n";

racers2 = racers.FindAll(new Predicate<Racer>(finder.DrivingCarPredicate));//返回泛型对象

foreach (Racer item in racers2)

{

label1.Text += item.ToString() + " ";

}

//委托查找一个元素(找到的第一个元素)

label1.Text += "\nFind(Car==\"L\")\n";

finder = new FindRacer("L2");

label1.Text += racers.Find(new Predicate<Racer>(finder.DrivingCarPredicate)).ToString();

//将查找出的元素做修改

racers.Find(new Predicate<Racer>(finder.DrivingCarPredicate)).Car = "L";

label1.Text += "\n将查找出元素修改过后\n";

finder = new FindRacer("L");

foreach (Racer item in racers.FindAll(new Predicate<Racer>(finder.DrivingCarPredicate)))

{

label1.Text += item.ToString() + " ";

}

//--------------------------------------------------------------------------------

/*

List<T>.ForEach()可以用于对每个元素执行一些操作.

它使用Action<T>委托对集合中的每个元素执行操作.Action<T>委托返回的类型是void.

*/

racers.ForEach(delegate(Racer r) { r.Car += "_CAR"; });

label1.Text += "\nList<T>.ForEach()全部修改对象\n";

foreach (Racer item in racers)

{

label1.Text += item.ToString() + " ";

}

//--------------------------------------------------------------------------------

/*

List<T>.Sort对元素进行排序

*/

//public void List<T>.Sort(Comparison<T>), 是一个委托方法,该方法带两个T类型参数;

racers.Sort(delegate(Racer r1, Racer r2) { return r1.Car.CompareTo(r2.Car); });

label1.Text += "\n 排序public void List<T>.Sort(Comparison<T>)\n";

foreach (Racer item in racers)

{

label1.Text += item.ToString() + " ";

}

//public void List<T>.Sort(IComparer<T>)

racers.Sort(new RacerComparer(RacerComparer.CompareType.Name));

label1.Text += "\n 排序public void List<T>.Sort(IComparer<T>)\n";

foreach (Racer item in racers)

{

label1.Text += item.ToString() + " ";

}

//--------------------------------------------------------------------------------

/*

类型转换

*/

List<Person> persons = racers.ConvertAll<Person>(delegate(Racer r)

{

int ixSeparator = r.Name.LastIndexOf(' ') + 1;

string lastname = r.Name.Substring(ixSeparator, r.Name.Length - ixSeparator);

string firstname = r.Name.Substring(0, ixSeparator - 1);

return(new Person(firstname, lastname));

});

label1.Text += "\n List<T>.ConvertAll类型转换\n";

foreach (Person item in persons)

{

label1.Text += item.ToString() + " ";

}

label1.Text += "\n 类型转换后的源数据\n";

foreach (Racer item in racers)

{

label1.Text += item.ToString() + " ";

}

//--------------------------------------------------------------------------------

}

//--------------------------------------------------------------------------------

//实体类

class Racer

{

private string name;

public string Name

{

get

{

return (name);

}

}

private string car;

public string Car

{

get

{

return (car);

}

set

{

car = value;

}

}

public Racer(string name, string car)

{

this.name = name;

this.car = car;

}

public override string ToString()

{

return name + "," + car;

}

}

//--------------------------------------------------------------------------------

//查找类

class FindRacer

{

private string car;

public FindRacer(string car)

{

this.car = car;

}

public bool DrivingCarPredicate(Racer racer)

{

return (racer.Car == car);

}

}

//排序类

class RacerComparer : IComparer<Racer>

{

public enum CompareType

{

Name, Car

}

private CompareType compareType;

public RacerComparer(CompareType compareType)

{

this.compareType = compareType;

}

public int Compare(Racer x, Racer y)

{

int result = 0;

switch (compareType)

{

case CompareType.Name:

{

result = x.Name.CompareTo(y.Name);

break;

}

case CompareType.Car:

{

result = x.Car.CompareTo(x.Car);

break;

}

}

return (result);

}

}

//--------------------------------------------------------------------------------

//类型转换类

public class Person

{

private string firstname;

private string lastname;

public Person(string firstname, string lastname)

{

this.firstname = firstname;

this.lastname = lastname;

}

public override string ToString()

{

return (firstname + "." + lastname);

}

}