I want to create a generalized method for sorting any kind of list by any kind of variable.

E.g. I have a Student and a Class entity:

Order(studentList, s => s.Name, desc)
Order(classList, s => s.ClassName, desc)

I have tried to create a private method for doing this:

private List<T> Order<T, TKey>(List<T> listToOrder, Expression<Func<T, TKey>> sortKey, bool desc)
{
   return desc ? listToOrder.OrderByDescending(sortKey) : listToOrder.OrderBy(sortKey)
}

But this obviously doesn't work. Any ideas how I can achieve this? Will edit the answer if it's not sufficient enough.

CodePudding user response：

If your Student & Class values are collected, you can try to write an extension method

1. return type might be IOrderedEnumerable<T> which type from OrderBy & OrderByDescending.
2. you might not need to use Expression just use delegate Func<T, TKey> will be enough

as below

public static class MyExtesion{
    public static IOrderedEnumerable<T> Order<T, TKey>(this IEnumerable<T> source,Func<T, TKey> sortKey, bool desc)
    {
        return desc ? source.OrderByDescending(sortKey) : source.OrderBy(sortKey);
    }
}

CodePudding user response：

If my understand is correct, try this :

    public static List<T> Order<T>(List<T> listToOrder, Func<T, int> sortFunc, bool desc)
    {
        return desc ?
            listToOrder.OrderByDescending(x => sortFunc(x)).ToList() : listToOrder.OrderBy(x => sortFunc(x)).ToList();
    }

Following is test codes:

var arr1 = new int[] {1,-1,2,-2,0,3,-3};
var result = LogHelper.Order(arr1.ToList(),x=>x*x,false);

Just log them.