以下为引用的内容：
装箱、转型、方法调用这些我们天天进行的日常工作之前到底有什么差别？ 以下为引用的内容：
struct UserInfoStruct
2{
3 public int UserId;
4 public string UserName;
5}
6class UserInfoClass
7{
8 private int UserId;
9 private string UserName;
10}
11class Program
12{
13
14 static void Main(string[] args)
15 {
16 object objString = "abc";
17
18 string aString = (string)objString;
19 string bString = objString.ToString();
20 string cString = Convert.ToString(objString);
21
22 object objInt = 5;
23 int aInt = (int)objInt;
24 int bInt = Convert.ToInt32(objInt);
25
26 object objStruct = new UserInfoStruct();
27 UserInfoStruct aUserInfoStruct = (UserInfoStruct)objStruct;
28
29 object objClass = new UserInfoClass();
30 UserInfoClass aUserInfoClass = (UserInfoClass)objClass;
31 }
32}
前几天在群里聊天，有人问：
string aString = (string)objString; string bString = objString.ToString();有什么区别，我当时就回答“一个是转型、一个是方法调用”，刚说完就觉得自己是在说废话，其实我也不知道内部到底发生了什么，如是就reflector,ILDASM,google一起上，现在把弄出来的结果整理了一下，share出来，并把相似的几个都集在一起讨论，由于我不懂WinDbg，所以无法深入，就浅尝辄止吧。 下面是main方法的IL代码： 以下为引用的内容：
1.method private hidebysig static void Main(string[] args) cil managed
2{
3 .entrypoint
4 // Code size 97 (0x61)
5 .maxstack 1
6 .locals init ([0] object objString,
7 [1] string aString,
8 [2] string bString,
9 [3] string cString,
10 [4] object objInt,
11 [5] int32 aInt,
12 [6] int32 bInt,
13 [7] object objStruct,
14 [8] valuetype SomeKits.UserInfoStruct aUserInfoStruct,
15 [9] object objClass,
16 [10] class SomeKits.UserInfoClass aUserInfoClass,
17 [11] valuetype SomeKits.UserInfoStruct CS$0$0000)
18 IL_0000: nop
19 IL_0001: ldstr "abc"
20 IL_0006: stloc.0
21 IL_0007: ldloc.0
22 IL_0008: castclass [mscorlib]System.String
23 IL_000d: stloc.1
24 IL_000e: ldloc.0
25 IL_000f: callvirt instance string [mscorlib]System.Object::ToString()
26 IL_0014: stloc.2
27 IL_0015: ldloc.0
28 IL_0016: call string [mscorlib]System.Convert::ToString(object)
29 IL_001b: stloc.3
30 IL_001c: ldc.i4.5
31 IL_001d: box [mscorlib]System.Int32
32 IL_0022: stloc.s objInt
33 IL_0024: ldloc.s objInt
34 IL_0026: unbox.any [mscorlib]System.Int32
35 IL_002b: stloc.s aInt
36 IL_002d: ldloc.s objInt
37 IL_002f: call int32 [mscorlib]System.Convert::ToInt32(object)
38 IL_0034: stloc.s bInt
39 IL_0036: ldloca.s CS$0$0000
40 IL_0038: initobj SomeKits.UserInfoStruct
41 IL_003e: ldloc.s CS$0$0000
42 IL_0040: box SomeKits.UserInfoStruct
43 IL_0045: stloc.s objStruct
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