List<>根据指定属性排序（实现IComparer接口）

问题：

   有一个List<CourseList> testlist,类CourseList中有CourseId, CourseName,CourseStatus,TeacherName,LevelName,StudentNumber这五个属性。现在想实现testlist的按CourseList类的各个属性排序。

 

解决办法：

 

public enum CompareType
{
    CourseId,
    CourseName,
    CourseStatus,
    TeacherName,
    LevelName,
    StudentNumber
}

 

public class CourseListComparer:IComparer<CourseList>
{

   
    private CompareType _compareColumn;

    public CompareType CompareColumn
    {
        get { return _compareColumn; }
        set { _compareColumn = value; }
    }

    public CourseListComparer(CompareType t) {
        this._compareColumn = t;

    }

    /// <summary>
    /// compare by different property
    /// </summary>
    /// <param name="x">CourseList x</param>
    /// <param name="y">CourseList y</param>
    /// <returns>int </returns>
    public int Compare(CourseList x,CourseList y) {

       
        switch (this.CompareColumn) {
            case CompareType.CourseId:
                return x.CourseId.CompareTo(y.CourseId);
            case CompareType.CourseName:
                return x.CourseName.CompareTo(y.CourseName);
            case CompareType.CourseStatus:
                return x.CourseStatus.CompareTo(y.CourseStatus);
            case CompareType.TeacherName:
                return x.TeacherName.CompareTo(y.TeacherName);
            case CompareType.LevelName:
                return x.LevelName.CompareTo(y.LevelName);
            case CompareType.StudentNumber:
                return x.StudentNumber.CompareTo(y.StudentNumber);
            default: return x.CourseId.CompareTo(y.CourseId);

        }
    }
}

CourseListComparer courselistComparer = new CourseListComparer(CompareType.CourseId);

testList.Sort(courselistComparer);

 

原因：

        C#中的List<>有两个Sort方法，一个是无参的，一个是带IComparer参的。无参的方法是按默认的比较器进行排序，有参的就要自己定义一个实现IComparer接口。

       实现ICompare接口就需要实现Compare方法。Compare方法有两个要比较的输入，根据自己定义的比较规则，返回int值，0表示相等，1表示x>y,-1表示x<y.