索引器的重载

1Companycom=newCompany();
2com.Departments.Add("HR");
3com.Departments.Add("Market");
4com.Departments.Add("Development");
5
6com.Departments[0].Staffs.Add("Alice");
7com.Departments[0].Staffs.Add("Amy");
8com.Departments[0].Staffs.Add("Ellen");
9com.Departments[2].Staffs.Add("Albert");
10com.Departments[2].Staffs.Add("Mark");
11com.Departments[2].Staffs.Add("Kevin");
12com.Departments[2].Staffs.Add("Neil");
13
14System.Console.WriteLine(com.Departments[0].Staffs[1].Name);

在循环处理的时候，第14行自然没有什么不好的地方，但如果像14行那样，要直接访问某个部门，用int的索引似乎显得太突兀。

我们优化DepartmentCollection的this索引器，重载this

1publicDepartmentthis[intindex]
2{
3set
4{
5this.List[index]=value;
6}
7get
8{
9return(Department)this.List[index];
10}
11}
12
13publicDepartmentthis[stringname]
14{
15get
16{
17for(inti=0;i<=this.List.Count-1;i++)
18{
19if(((Department)this.List[i]).Name==name)
20{
21returnthis[i];
22}
23}
24returnnull;
25}
26
27}

然后，我们继续优化Department

1publicclassDepartment
2{
3publicStaffCollectionStaffs=newStaffCollection();
4
5publicDepartment(stringname)
6{
7Name=name;
8}
9publicreadonlystringName;
10
11publicStaffthis[intindex]
12{
13set
14{
15Staffs[index]=value;
16}
17get
18{
19returnStaffs[index];
20}
21}
22}

加了第11行的this。

现在的调用代码是

1Companycom=newCompany();
2com.Departments.Add("HR");
3com.Departments.Add("Market");
4com.Departments.Add("Development");
5
6com.Departments[0].Staffs.Add("Alice");
7com.Departments[0].Staffs.Add("Amy");
8com.Departments[0].Staffs.Add("Ellen");
9com.Departments[2].Staffs.Add("Albert");
10com.Departments[2].Staffs.Add("Mark");
11com.Departments[2].Staffs.Add("Kevin");
12com.Departments[2].Staffs.Add("Neil");
13
14System.Console.WriteLine(com.Departments["Development"][1].Name);

注意第14行，是不是优雅多了啊？