在Igroup中对内部集合进行排序<Tkey,Tsource>

Question

I have a list of employees, grouped by department name in an IEnumerable<IGrouping<string, employee>> (variable name depgrpname_sal_sort ).

I want to display this groups of collections in sorted order by their salaries in each group.

I tried this and got the result:

foreach (var depgroupname in depgrpname_sal_sort) {
    Console.WriteLine(depgroupname.Key);
    var group = depgroupname.Where(g => g.depaname == depgroupname.Key);

    foreach (employee e in group.OrderBy(e=>e.salary)) {
        Console.WriteLine(e.empId + " " + e.empname + " " + e.depaname + " " + e.salary);
    }
}

Output:

Development
    105 John garry Development 45000
    103 Mark Development 55000
HR
    102 Roger HR 25000
    101 John D HR 35000
Testing
    104 John Testing 25000

am i correct or is there any predefined technique/method to sort the inner lists.
thanks in advance

Answer 1

That is sorted, but if you want the highest salary at the top then you need to use OrderByDescending . Example:

foreach (Employee e in group.OrderByDescending(e => e.salary)) {
    // print...
}

---

Edit

You asked how you could make the sorting more direct...first off you could improve the grouping:

var employees = new List<Employee>() {
    new Employee("John", "Development", 45000),
    new Employee("Mark", "Development", 55000),
    new Employee("Roger", "HR", 25000),
    new Employee("Jeff", "HR", 35000),
    new Employee("James", "Testing", 25000)
};


foreach (var g in employees.GroupBy(x => x.Dept)) {
    Console.WriteLine(g.Key);
    foreach (var e in g.OrderByDescending(x => x.Salary)) {
        Console.WriteLine(" - {0} makes ${1}/year", e.Name, e.Salary);
    }
}

That way you only group everything once, as opposed to grouping pre-grouped data. If you want to group everything by Department then sort it and save it grouped and sorted for later , then I would recommend converting it to a Dictionary<string, List<Employee>> :

var employees = new List<Employee>() {
    new Employee("John", "Development", 45000),
    new Employee("Mark", "Development", 55000),
    new Employee("Roger", "HR", 25000),
    new Employee("Jeff", "HR", 35000),
    new Employee("James", "Testing", 25000)
};

var grouped = employees.GroupBy(x => x.Dept)
                       .ToDictionary(
                           key => key.Key, 
                           value => new List<Employee>(value.OrderByDescending(x => x.Salary))
                       );

foreach (var g in grouped) {
    Console.WriteLine(g.Key);
    foreach (var e in g.Value) {
        Console.WriteLine(" - {0} makes ${1}/year", e.Name, e.Salary);
    }
}