CIL之——值类型与引用类型的声明和使用

在C#代码中调用值类型的变量和调用引用类型的变量没什么区别，但是在CIL代码中就有不一样了，下面让我们看一下CIL代码是如何实现这一功能的吧！

C#目标代码

namespace ConsoleTest{    public class Program    {        public static void Main(string[] args)        {            Person objPerson = new Person();            WorkExperience resume = objPerson.GetResume();            Console.WriteLine("timeArea:{0} company:{1}", resume.TimeArea, resume.Company);            int age = objPerson.GetAge();            Console.WriteLine("age:{0}", age);                        Console.ReadKey();        }    }    public class Person    {        private string name;        private int age;        private WorkExperience workExperience;        public Person()        {        }        public Person(string name, int age, WorkExperience workExperience)        {            this.name = name;            this.age = age;            this.workExperience = workExperience;        }        public WorkExperience GetResume()        {            WorkExperience workExperience = new WorkExperience("2010-06-11", "BigData");            return workExperience;        }        public int GetAge()        {            int age = 12;            return age;        }    }    public class WorkExperience    {        public string TimeArea { get; set; }        public string Company { get; set; }        public WorkExperience()        {                    }           public WorkExperience(string timeArea,string company)        {            this.TimeArea = timeArea;            this.Company = company;        }            }}

对应CIL代码

.namespace ConsoleTest{       .class public Program extends [mscorlib]System.Object    {        .method public void .ctor()        {            .maxstack 8            ldarg.0            call instance void [mscorlib]System.Object::.ctor()            ret        }        .method public static void Main(string[] args)        {            .entrypoint            .maxstack 3            .locals init(                //声明引用类型的局部变量必须加class关键字且类型必须使用类的全称                [0] class ConsoleTest.Person objPerson,                [1] class ConsoleTest.WorkExperience resume,                //声明值类型的局部变量直接使用类型即可                [2] int32 age            )            newobj instance void ConsoleTest.Person::.ctor()            stloc.0            ldloc.0            //返回值为引用类型时必须加class关键字且类型必须使用类的全称            call instance class ConsoleTest.WorkExperience ConsoleTest.Person::GetResume()            stloc.1            ldstr "timeArea:{0} company:{1}"            ldloc.1            //返回值为值类型时直接使用类型即可            call instance string ConsoleTest.WorkExperience::get_TimeArea()            ldloc.1            call instance string ConsoleTest.WorkExperience::get_Company()            call void [mscorlib]System.Console::WriteLine(string,object,object)            ldloc.0            call instance int32 ConsoleTest.Person::GetAge()            stloc.2            ldstr "age:{0}"            ldloc.2            box int32            call void [mscorlib]System.Console::WriteLine(string,object)            call valuetype [mscorlib]System.ConsoleKeyInfo [mscorlib]System.Console::ReadKey()            pop            ret        }    }    .class public Person    {        .field private string name        //声明值类型的字段时直接使用类型即可        .field private string age        //声明引用类型的字段时必须加class关键字且类型必须使用类的全称        .field private class ConsoleTest.WorkExperience workExperience        .method public void .ctor()        {            .maxstack 1            ldarg.0            call instance void [mscorlib]System.Object::.ctor()            ret        }        //值类型的参数直接使用类型即可        //引用类型的参数必须加class关键字且类型必须使用类的全称        .method public void .ctor(string name,int32 age,class ConsoleTest.WorkExperience workExperience)        {            .maxstack 1            ldarg.0            call instance void [mscorlib]System.Object::.ctor()            ldarg.0            ldarg.1            stfld string ConsoleTest.Person::name            ldarg.0            ldarg.2            //对值类型的字段赋值时直接使用类型即可            stfld int32 ConsoleTest.Person::age            ldarg.0            ldarg.3            //对引用类型的字段赋值时必须加class关键字且类型必须使用类的全称            stfld class ConsoleTest.WorkExperience ConsoleTest.Person::workExperience            ret        }        //返回值为引用类型时必须加class关键字且类型必须使用类的全称        .method public class ConsoleTest.WorkExperience GetResume()        {            .maxstack 2            .locals init(                class ConsoleTest.WorkExperience workExperience            )            ldstr "2010-06-11"            ldstr "BigData"            newobj instance void ConsoleTest.WorkExperience::.ctor(string,string)            stloc.0            ldloc.0            ret        }        //返回值为值类型时直接使用类型即可        .method public int32 GetAge()        {            .maxstack 1            .locals init(                int32 age            )            ldc.i4 12            stloc.0            ldloc.0            ret        }    }    .class public WorkExperience    {        .field private string _timeArea        .field private string _company        .method public void .ctor()        {            .maxstack 1            ldarg.0            call instance void [mscorlib]System.Object::.ctor()            ret        }        .method public void .ctor(string timeArea,string company)        {            .maxstack 2            ldarg.0            call instance void [mscorlib]System.Object::.ctor()            ldarg.0            ldarg.1            call instance void ConsoleTest.WorkExperience::set_TimeArea(string)            ldarg.0            ldarg.2            call instance void ConsoleTest.WorkExperience::set_Company(string)            ret        }        .method public string get_Company()        {            .maxstack 1            .locals init(                string company            )            ldarg.0            ldfld string ConsoleTest.WorkExperience::_company            stloc.0            ldloc.0            ret        }        .method public void set_Company(string val)        {            .maxstack 1            ldarg.0            ldarg.1            stfld string ConsoleTest.WorkExperience::_company            ret        }        .method public string get_TimeArea()        {            .maxstack 1            .locals init(                string timeArea            )            ldarg.0            ldfld string ConsoleTest.WorkExperience::_timeArea            stloc.0            ldloc.0            ret        }        .method public void set_TimeArea(string val)        {            .maxstack 1            ldarg.0            ldarg.1            stfld string ConsoleTest.WorkExperience::_timeArea            ret        }        .property instance string Company()        {            .set instance void ConsoleTest.WorkExperience::set_Company(string)            .get instance string ConsoleTest.WorkExperience::get_Company()        }        .property instance string TimeArea()        {            .set instance void ConsoleTest.WorkExperience::set_TimeArea(string)            .get instance string ConsoleTest.WorkExperience::get_TimeArea()        }    }}