使用 LINQ 对列表及其所有嵌套对象进行排序
本文关键字：对象 嵌套 排序 LINQ 列表 使用 | 更新日期: 2023-09-27 18:31:50
有一个组织有几个部门，每个部门都有几名员工。
我创建了以下对象模型：
public class Organisation
{
public int Code { get; set; }
public string Type { get; set; }
public string Name { get; set; }
public List<Department> Departments { get; set; }
}
public class Department
{
public int Code { get; set; }
public string Name { get; set; }
public List<Employee> Employees { get; set; }
}
public class Employee
{
public int Code { get; set; }
public string Name { get; set; }
}
现在，我有一个这些组织的列表，使用 LINQ，我想对输出进行排序/排序，如下所示：
1） 组织：按代码和名称排序
2）部门：按代码和名称排序
3）员工：按代码和姓名排序
以下是我填充的一些测试数据：
var britishTelecomLtd = new Organisation
{
Code = 8,
Name = "British Telecom Ltd",
Type = "Institutional",
Departments = new List<Department>
{
new Department
{
Code = 6,
Name = "Finance",
Employees = new List<Employee>
{
new Employee
{
Code = 5,
Name = "Peter"
},
new Employee
{
Code = 2,
Name = "James"
},
new Employee
{
Code = 6,
Name = "Andrew"
}
}
},
new Department
{
Code = 5,
Name = "Accounts",
Employees = new List<Employee>
{
new Employee
{
Code = 15,
Name = "Jane"
},
new Employee
{
Code = 22,
Name = "John"
},
new Employee
{
Code = 16,
Name = "Mark"
}
}
}
}
};
var virginMediaLtd = new Organisation
{
Code = 5,
Name = "Virgin Media Ltd",
Type = "Institutional",
Departments = new List<Department>
{
new Department
{
Code = 6,
Name = "Sales",
Employees = new List<Employee>
{
new Employee
{
Code = 5,
Name = "Peter"
},
new Employee
{
Code = 2,
Name = "James"
},
new Employee
{
Code = 6,
Name = "Andrew"
}
}
},
new Department
{
Code = 5,
Name = "Support",
Employees = new List<Employee>
{
new Employee
{
Code = 15,
Name = "Jane"
},
new Employee
{
Code = 22,
Name = "John"
},
new Employee
{
Code = 16,
Name = "Mark"
}
}
}
}
};
var pcWorldLtd = new Organisation
{
Code = 18,
Name = "PC World Ltd",
Type = "Retail",
Departments = new List<Department>
{
new Department
{
Code = 6,
Name = "Marketing",
Employees = new List<Employee>
{
new Employee
{
Code = 15,
Name = "Jane"
},
new Employee
{
Code = 22,
Name = "John"
},
new Employee
{
Code = 16,
Name = "Mark"
}
}
},
new Department
{
Code = 5,
Name = "Customer Services",
Employees = new List<Employee>
{
new Employee
{
Code = 5,
Name = "Kelly"
},
new Employee
{
Code = 2,
Name = "Jenny"
},
new Employee
{
Code = 6,
Name = "Tricia"
}
}
}
}
};
var blueCatLtd = new Organisation
{
Code = 3,
Name = "Blue Cat Music Ltd",
Type = "Retail",
Departments = new List<Department>
{
new Department
{
Code = 6,
Name = "Sales",
Employees = new List<Employee>
{
new Employee
{
Code = 5,
Name = "Peter"
},
new Employee
{
Code = 2,
Name = "James"
},
new Employee
{
Code = 6,
Name = "Andrew"
}
}
},
new Department
{
Code = 5,
Name = "Warehouse",
Employees = new List<Employee>
{
new Employee
{
Code = 5,
Name = "Andy"
},
new Employee
{
Code = 2,
Name = "Robert"
},
new Employee
{
Code = 6,
Name = "Dave"
}
}
}
}
};
var organisations = new List<Organisation>
{
britishTelecomLtd,
virginMediaLtd,
pcWorldLtd,
blueCatLtd
};
在这里，我将数据添加到字典中：
var legalEntitiesCollectionByType = new Dictionary<string, ICollection<Organisation>>
{
{
"Institutional", organisations
.Where(x => x.Type == "Institutional")
.OrderBy(x => x.Code).ThenBy(x => x.Name)
.ToList()
},
{
"Retail", organisations
.Where(x => x.Type == "Retail")
.OrderBy(x => x.Code).ThenBy(x => x.Name)
.ToList()
}
};
这样做，排序只发生在组织级别，而不是部门或员工级别。
我的问题是，如何在填充上面的字典时实现对象层次结构中所有 3 个级别的排序？
干杯
我知道
这是一个老问题，但有一种更简单的方法可以实现相同的结果：
organisations = organisations.OrderBy(org =>
{
org.Departments = org.Departments
.OrderBy(dept =>
{
dept.Employees = dept.Employees
.OrderBy(employee => employee.Code)
.ThenBy(employee=>employee.Name);
return dept.Code;
})
.ThenBy(dept=>dept.Name);
return org.Code;
})
.ThenBy(org=>org.Name);
您需要在返回的对象中进行所有三个级别的排序，如下所示（我只显示"Retail"，"Institutional"需要以相同的方式排序）：
{
"Retail", organisations
.Where(x => x.Type == "Retail")
.OrderBy(x => x.Code).ThenBy(x => x.Name)
.Select(x => new Organisation {
x.Code
, x.Type
, x.Name
, Departments = x.Departmentsd.OrderBy(d => d.Code).ThenBy(d => d.Name)
.Select(d => new Department {
d.Code
, d.Name
, Employees = d.Employees.OrderBy(e => e.Code).ThenBy(e => e.Name).ToList()
})
}).ToList()
}
由于需要多次选择此选项，因此可能需要将此代码包装在方法中，并从多个位置使用它，如下所示：
private Organisation SortedOrganisation(Organisation x) {
return new Organisation {
x.Code
, x.Type
, x.Name
, Departments = x.Departmentsd.OrderBy(d => d.Code).ThenBy(d => d.Name)
.Select(d => new Department {
d.Code
, d.Name
, Employees = d.Employees.OrderBy(e => e.Code).ThenBy(e => e.Name).ToList()
})
};
}
...
var legalEntitiesCollectionByType = new Dictionary<string, ICollection<Organisation>>
{
{
"Institutional", organisations
.Where(x => x.Type == "Institutional")
.OrderBy(x => x.Code).ThenBy(x => x.Name)
.Select(SortedOrganisation)
.ToList()
},
{
"Retail", organisations
.Where(x => x.Type == "Retail")
.OrderBy(x => x.Code).ThenBy(x => x.Name)
.Select(SortedOrganisation)
.ToList()
}
};
您可以在以下之前排序：
organisations.ToList().ForEach(o => o.Departments = o.Departments.OrderBy(d => d.Code).ToList());
organisations.SelectMany(o => o.Departments).ToList().ForEach(d => d.Employees = d.Employees.OrderBy(e => e.Name).ToList());
然后使用已经排序的列表
var legalEntitiesCollectionByType = new Dictionary<string, ICollection<Organisation>>
{
{
"Institutional", organisations
.Where(x => x.Type == "Institutional")
.ToList()
},
{
"Retail", organisations
.Where(x => x.Type == "Retail")
.ToList()
}
};
注意：排序不到位，您可以使用comparer来实现此目的
organisations.ToList().ForEach(o => o.Departments.Sort(CreateCustomComparison));
organisations.SelectMany(o => o.Departments).ToList().ForEach(d => d.Employees.Sort(CreateCustomComparison));
如果需要按代码和名称对Employees排序，则可以将该属性设置为SortedList<>。
public class Department
{
...
public SortedList<Tuple<int, string>, Employee> Employees { get; set; }
}
在 .NET 4 之前，您可以使用 KeyValuePair 而不是 Tuple 。
创建Employees对象时，您需要为排序列表的键提供IComparer对象。
Employees = new SortedList<Tuple<int, string>, Employee>(new EmployeeKeyComparer());
其中EmployeeKeyComparer可以定义为
public class EmployeeKeyComparer : IComparer<Tuple<int, string>>
{
public int Compare(Tuple<int, string> x, Tuple<int, string> y)
{
if (x.First == y.First)
return StringComparer.Ordinal.Compare(x.Second, y.Second);
else
return x.First.CompareTo(y.First);
}
}
var legalEntitiesCollectionByType = new Dictionary<string, ICollection<Organisation>>
{
{
"Institutional", organisations
.Where(x => x.Type == "Institutional")
.ToList()
.Select(o => new Organisation{Code = x.Code,Departaments = x.Departaments.OrderBy(c => c).ToList() }).ToList()
}
}