IList的排序问题

lw7210 2010-04-23 09:59:12

不知道怎么对IList<T>进行排序,在网上找了些资料,都是对List<T>进行排序的,对IList<T>的OrderBy方法也搞不懂,有谁能提供一个详细的IList<T>的排序代码,List<T>的就不要了.

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lw7210 2010-04-24

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可是这种写法pets.OrderBy(pet => pet.Age);在我的电脑上不行啊,我用的是3.5啊

lw7210 2010-04-24

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也就是说要用3.0才能用

阿非 2010-04-24

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什么?

lw7210 2010-04-24

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这个例子是对数据组进行排序,不是对IList<T>进行排序.

阿非 2010-04-24

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怎么个不好用

这个写法是使用 pet.Age 进行升序排序

阿非 2010-04-23

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OrderBy 也是 3.0 的扩展方法

阿非 2010-04-23

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[Quote=引用 7 楼 lw7210 的回复:]

http://msdn.microsoft.com/zh-cn/library/bb534966(v=VS.95).aspx
在这里找到点资料,都没看懂,IEnumerable<Pet> query = pets.OrderBy(pet => pet.Age);这是C#的语法吗?

class Pet
{
……
[/Quote]

是 Lambda 表达式

http://msdn.microsoft.com/zh-cn/library/bb397687.aspx

mngzilin 2010-04-23

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[Quote=引用 2 楼 wuyq11 的回复:]
private int Compare(T x, T y)
{
PropertyInfo property = typeof( T ).GetProperty(_propertyName);
switch (property.PropertyType.ToString()) {
case "System.Int32" :
int int1 = 0;
int i……
[/Quote]

ikiss 2010-04-23

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lw7210 2010-04-23

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http://msdn.microsoft.com/zh-cn/library/bb534966(v=VS.95).aspx
在这里找到点资料,都没看懂,IEnumerable<Pet> query = pets.OrderBy(pet => pet.Age);这是C#的语法吗?

class Pet
{
public string Name { get; set; }
public int Age { get; set; }
}

public static void OrderByEx1(System.Windows.Controls.TextBlock outputBlock)
{
Pet[] pets = { new Pet { Name="Barley", Age=8 },
new Pet { Name="Boots", Age=4 },
new Pet { Name="Whiskers", Age=1 } };

IEnumerable<Pet> query = pets.OrderBy(pet => pet.Age);

foreach (Pet pet in query)
outputBlock.Text += "\n" + String.Format("{0} - {1}", pet.Name, pet.Age);
}

/*
This code produces the following output:

Whiskers - 1
Boots - 4
Barley - 8
*/

皇城龙三 2010-04-23

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using System;

using System.Collections.Generic;

using System.Text;

using System.Reflection;



namespace Business.common

{

    /// <summary>

    /// IList排序类

    /// </summary>

    /// <typeparam name="T"></typeparam>

    public class IListSort<T>

    {

        private string _propertyName;

        private bool _sortBy = true;

        private IList<T> _list;



        /// <summary>

        /// 构造函数

        /// </summary>

        /// <param name="list">排序的Ilist</param>

        /// <param name="propertyName">排序字段属性名</param>

        /// <param name="sortBy">true升序 false 降序 不指定则为true</param>

        public IListSort(IList<T> list, string propertyName, bool sortBy)

        {

            _list = list;

            _propertyName = propertyName;

            _sortBy = sortBy;

        }

        /// <summary>

        /// 构造函数

        /// </summary>

        /// <param name="list">排序的Ilist</param>

        /// <param name="propertyName">排序字段属性名</param>

        /// <param name="sortBy">true升序 false 降序 不指定则为true</param>

        public IListSort(IList<T> list, string propertyName)

        {

            _list = list;

            _propertyName = propertyName;

            _sortBy = true;

        }



        /// <summary>

        /// IList

        /// </summary>

        public IList<T> List

        {

            get { return _list; }

            set { _list = value; }

        }



        /// <summary>

        /// 排序字段属性名

        /// </summary>

        public string PropertyName

        {

            get { return _propertyName; }

            set { _propertyName = value; }

        }



        /// <summary>

        /// true升序 false 降序

        /// </summary>

        public bool SortBy

        {

            get { return _sortBy; }

            set { _sortBy = value;}

        }



        /// <summary>

        /// 排序，插入排序方法

        /// </summary>

        /// <returns></returns>

        public IList<T> Sort()

        {

            if (_list.Count == 0) return _list;

            for (int i = 1; i < _list.Count; i++) {

                T t = _list[i];

                int j = i;

                while ((j > 0) && Compare(_list[j - 1], t) < 0) {

                    _list[j] = _list[j - 1];

                    --j;

                }

                _list[j] = t;

            }

            return _list;

        }

        

        /// <summary>

        /// 比较大小 返回值 小于零则X小于Y，等于零则X等于Y，大于零则X大于Y

        /// </summary>

        /// <param name="x"></param>

        /// <param name="y"></param>

        /// <returns></returns>

        private int Compare(T x, T y)

        {

            if (string.IsNullOrEmpty(_propertyName)) throw new ArgumentNullException("没有指字对象的排序字段属性名!");

            PropertyInfo property = typeof( T ).GetProperty(_propertyName);

            if (property == null) throw new ArgumentNullException("在对象中没有找到指定属性!");



            switch (property.PropertyType.ToString()) { 

                case "System.Int32" :

                    int int1 = 0;

                    int int2 = 0;

                    if (property.GetValue(x, null) != null) {

                        int1 = Convert.ToInt32(property.GetValue(x, null));

                    }

                    if (property.GetValue(y, null) != null) {

                        int2 = Convert.ToInt32(property.GetValue(y, null));

                    }

                    if (_sortBy) {

                        return int2.CompareTo(int1);

                    }

                    else {

                        return int1.CompareTo(int2);

                    }

                    break;

                case "System.Double":

                    double double1 = 0;

                    double double2 = 0;

                    if (property.GetValue(x, null) != null) {

                        double1 = Convert.ToDouble(property.GetValue(x, null));

                    }

                    if (property.GetValue(y, null) != null) {

                        double2 = Convert.ToDouble(property.GetValue(y, null));

                    }

                    if (_sortBy) {

                        return double2.CompareTo(double1);

                    }

                    else {

                        return double1.CompareTo(double2);

                    }

                    break;

                case "System.String" :

                    string string1 = string.Empty;

                    string string2 = string.Empty;

                    if (property.GetValue(x, null) != null) {

                        string1 = property.GetValue(x, null).ToString();

                    }

                    if (property.GetValue(y, null) != null) {

                        string2 = property.GetValue(y, null).ToString();

                    }

                    if (_sortBy) {

                        return string2.CompareTo(string1);

                    }

                    else {

                        return string1.CompareTo(string2);

                    }

                    break;

                case "System.DateTime":

                    DateTime DateTime1 = DateTime.Now;

                    DateTime DateTime2 = DateTime.Now;

                    if (property.GetValue(x, null) != null) {

                        DateTime1 = Convert.ToDateTime(property.GetValue(x, null));

                    }

                    if (property.GetValue(y, null) != null) {

                        DateTime2 = Convert.ToDateTime(property.GetValue(y, null));

                    }

                    if (_sortBy) {

                        return DateTime2.CompareTo(DateTime1);

                    }

                    else {

                        return DateTime1.CompareTo(DateTime2);

                    }

                    break;

            }

            return 0;

        }

    }

}



调用：





            IList<MVote> list=new MVoteClassDAL().lazilyLoad(int.Parse(Request.QueryString["Id"])).M_Votes;   

            this.GridView1.DataSource = new IListSort<MVote>(list, "SortOrder").Sort();

            this.GridView1.DataBind();

lw7210 2010-04-23

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以上这些都是针对List<T>的吧,IList<T>并没有Sort方法,只有OrderBy方法.不知道怎么用

vip__888 2010-04-23

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微工程 2010-04-23

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private int Compare(T x, T y)
{
PropertyInfo property = typeof( T ).GetProperty(_propertyName);
switch (property.PropertyType.ToString()) {
case "System.Int32" :
int int1 = 0;
int int2 = 0;
if (property.GetValue(x, null) != null) {
int1 = Convert.ToInt32(property.GetValue(x, null));
}
if (property.GetValue(y, null) != null) {
int2 = Convert.ToInt32(property.GetValue(y, null));
}
return int2.CompareTo(int1);
}
break;
case "System.Double":
double double1 = 0;
double double2 = 0;
if (property.GetValue(x, null) != null) {
double1 = Convert.ToDouble(property.GetValue(x, null));
}
if (property.GetValue(y, null) != null) {
double2 = Convert.ToDouble(property.GetValue(y, null));
}
return double1.CompareTo(double2);
}
break;
default:break;
}

public class Student
{
public string Name{get;set;}
public string Age{get;set;}
}
public class StudentComparer : IComparer<Student>
{
public enum CompareType
{
Name,
Age
}
private CompareType type;
public StudentComparer(CompareType type)
{
this.type = type;
}
public int Compare(Student x, Student y)
{
switch(this.type)
{
case CompareType.Name:
return x.Name.CompareTo(y.Name);
defaqult:
return x.Age.CompareTo(y.Age);
}
}
}

wuyq11 2010-04-23

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threenewbee 2010-04-23

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参考：http://msdn.microsoft.com/zh-cn/library/system.icomparable(VS.90).aspx

关键，实现IComparable，也就是说系统可以帮你排序，但是你总得告诉系统，比较大小的依据。

完美实现了IList绑定到DataGridView时的各列排序问题，Check列表头全选问题。