===================================
1
class TestConstruct{
private int var_int;
private double var_double;
private string var_string;
}
.ctor:void() //默认的无参构造函数
.method public hidebysig specialname rtspecialname
instance void .ctor() cil managed
{
// 代码大小 7 (0x7)
.maxstack 8
IL_0000: ldarg.0
IL_0001: call instance void [mscorlib]System.Object::.ctor() //调用基类构造函数
IL_0006: ret
} // end of method TestConstruct::.ctor
===========================================
2
class TestConstruct{
private int var_int=2;
private double var_double=2.5;
private string var_string;
}
.ctor:void() //默认的无参构造函数
.method public hidebysig specialname rtspecialname
instance void .ctor() cil managed
{
// 代码大小 30 (0x1e)
.maxstack 8
IL_0000: ldarg.0
IL_0001: ldc.i4.2
IL_0002: stfld int32 ConsoleTest.TestConstruct::var_int
IL_0007: ldarg.0
IL_0008: ldc.r8 2.5 //现初始化默认值
IL_0011: stfld float64 ConsoleTest.TestConstruct::var_double
IL_0016: ldarg.0
IL_0017: call instance void [mscorlib]System.Object::.ctor() //然后再调用基本构造函数
IL_001c: nop
IL_001d: ret
} // end of method TestConstruct::.ctor
比较 1 2 说明了什么问题。
=====================================================
3
class TestConstruct{
private int var_int=2;
private double var_double=2.5;
private string var_string;
public TestConstruct(){
}
}
.ctor:void() //自定义的无参构造函数
.method public hidebysig specialname rtspecialname
instance void .ctor() cil managed
{
// 代码大小 32 (0x20)
.maxstack 8
IL_0000: ldarg.0
IL_0001: ldc.i4.2
IL_0002: stfld int32 ConsoleTest.TestConstruct::var_int
IL_0007: ldarg.0
IL_0008: ldc.r8 2.5
IL_0011: stfld float64 ConsoleTest.TestConstruct::var_double
IL_0016: ldarg.0
IL_0017: call instance void [mscorlib]System.Object::.ctor()
IL_001c: nop
IL_001d: nop
IL_001e: nop
IL_001f: ret
} // end of method TestConstruct::.ctor
==========================================================
4
class TestConstruct{
private int var_int=2;
private double var_double=2.5;
private string var_string;
public TestConstruct(){
this.var_double = 9.8;
this.var_string = "TestConstruct";
}
}
.ctor:void() //自定义的无参构造函数
.method public hidebysig specialname rtspecialname
instance void .ctor() cil managed
{
// 代码大小 58 (0x3a)
.maxstack 8
IL_0000: ldarg.0
IL_0001: ldc.i4.2
IL_0002: stfld int32 ConsoleTest.TestConstruct::var_int
IL_0007: ldarg.0
IL_0008: ldc.r8 2.5 //执行默认无参构造函数
IL_0011: stfld float64 ConsoleTest.TestConstruct::var_double
IL_0016: ldarg.0
IL_0017: call instance void [mscorlib]System.Object::.ctor() //然后执行基类构造函数
IL_001c: nop
IL_001d: nop
IL_001e: ldarg.0
IL_001f: ldc.r8 9.8000000000000007
IL_0028: stfld float64 ConsoleTest.TestConstruct::var_double
IL_002d: ldarg.0
IL_002e: ldstr "TestConstruct" //最后才执行自定义无参默认构造函数中的代码
IL_0033: stfld string ConsoleTest.TestConstruct::var_string
IL_0038: nop
IL_0039: ret
} // end of method TestConstruct::.ctor
比较 2 3 4说明一个问题：自定义无参构造函数的代码执行过程，具体见我在上面的注释
这样的代码，变量的值改变2次，代码量也比较多，建议 使用构造函数中调用构造函数
==================================================================
5
class TestConstruct{
private int var_int=2;
private double var_double=2.5;
private string var_string;
public TestConstruct() {
}
public TestConstruct(string var){
this.var_string = var;
}
}
.ctor:void() //自定义的无参构造函数
.method public hidebysig specialname rtspecialname
instance void .ctor() cil managed
{
// 代码大小 32 (0x20)
.maxstack 8
IL_0000: ldarg.0
IL_0001: ldc.i4.2
IL_0002: stfld int32 ConsoleTest.TestConstruct::var_int
IL_0007: ldarg.0
IL_0008: ldc.r8 2.5
IL_0011: stfld float64 ConsoleTest.TestConstruct::var_double
IL_0016: ldarg.0
IL_0017: call instance void [mscorlib]System.Object::.ctor()
IL_001c: nop
IL_001d: nop
IL_001e: nop
IL_001f: ret
} // end of method TestConstruct::.ctor
.ctor:void(string) //自定义的有参数构造函数
.method public hidebysig specialname rtspecialname
instance void .ctor(string var) cil managed
{
// 代码大小 39 (0x27)
.maxstack 8
IL_0000: ldarg.0
IL_0001: ldc.i4.2
IL_0002: stfld int32 ConsoleTest.TestConstruct::var_int
IL_0007: ldarg.0
IL_0008: ldc.r8 2.5
IL_0011: stfld float64 ConsoleTest.TestConstruct::var_double
IL_0016: ldarg.0
IL_0017: call instance void [mscorlib]System.Object::.ctor()
IL_001c: nop
IL_001d: nop
IL_001e: ldarg.0
IL_001f: ldarg.1
IL_0020: stfld string ConsoleTest.TestConstruct::var_string
IL_0025: nop
IL_0026: ret
} // end of method TestConstruct::.ctor
=====================================================================
class TestConstruct{
private int var_int=2;
private double var_double=2.5;
private string var_string;
public TestConstruct() {
}
public TestConstruct(string var){
this.var_double=9.5;
this.var_string = var;
}
}
.ctor:void() //自定义的无参构造函数
.method public hidebysig specialname rtspecialname
instance void .ctor() cil managed
{
// 代码大小 32 (0x20)
.maxstack 8
IL_0000: ldarg.0
IL_0001: ldc.i4.2
IL_0002: stfld int32 ConsoleTest.TestConstruct::var_int
IL_0007: ldarg.0
IL_0008: ldc.r8 2.5
IL_0011: stfld float64 ConsoleTest.TestConstruct::var_double
IL_0016: ldarg.0
IL_0017: call instance void [mscorlib]System.Object::.ctor()
IL_001c: nop
IL_001d: nop
IL_001e: nop
IL_001f: ret
} // end of method TestConstruct::.ctor
.method public hidebysig specialname rtspecialname
instance void .ctor(string var) cil managed
{
// 代码大小 54 (0x36)
.maxstack 8
IL_0000: ldarg.0
IL_0001: ldc.i4.2
IL_0002: stfld int32 ConsoleTest.TestConstruct::var_int
IL_0007: ldarg.0
IL_0008: ldc.r8 2.5
IL_0011: stfld float64 ConsoleTest.TestConstruct::var_double
IL_0016: ldarg.0
IL_0017: call instance void [mscorlib]System.Object::.ctor()
IL_001c: nop
IL_001d: nop
IL_001e: ldarg.0
IL_001f: ldc.r8 9.5
IL_0028: stfld float64 ConsoleTest.TestConstruct::var_double
IL_002d: ldarg.0
IL_002e: ldarg.1
IL_002f: stfld string ConsoleTest.TestConstruct::var_string
IL_0034: nop
IL_0035: ret
} // end of method TestConstruct::.ctor
=====================================================================
二：继承关系中的构造函数
class Father
{
private int father_int;
private Double father_double;
public Father()
{
this.father_int = 1;
this.father_double = 1.1;
}
}
class Son : Father
{
private int son_int;
private double son_double;
public Son()
{
this.son_int = 2;
this.son_double = 2.2;
}
}
//====== .ctor() Son的自定义构造函数============
.method public hidebysig specialname rtspecialname
instance void .ctor() cil managed
{
// 代码大小 32 (0x20)
.maxstack 8
IL_0000: ldarg.0
IL_0001: call instance void ConsoleTest.Father::.ctor() //先调用基类的构造函数
IL_0006: nop
IL_0007: nop
IL_0008: ldarg.0
IL_0009: ldc.i4.2
IL_000a: stfld int32 ConsoleTest.Son::son_int //然后再执行子类中的代码
IL_000f: ldarg.0
IL_0010: ldc.r8 2.2000000000000002
IL_0019: stfld float64 ConsoleTest.Son::son_double
IL_001e: nop
IL_001f: ret
} // end of method Son::.ctor
//====== .ctor() Father的自定义构造函数============
.method public hidebysig specialname rtspecialname
instance void .ctor() cil managed
{
// 代码大小 32 (0x20)
.maxstack 8
IL_0000: ldarg.0
IL_0001: call instance void [mscorlib]System.Object::.ctor() //先调用基类的构造函数
IL_0006: nop
IL_0007: nop
IL_0008: ldarg.0
IL_0009: ldc.i4.1
IL_000a: stfld int32 ConsoleTest.Father::father_int
IL_000f: ldarg.0
IL_0010: ldc.r8 1.1000000000000001
IL_0019: stfld float64 ConsoleTest.Father::father_double
IL_001e: nop
IL_001f: ret
} // end of method Father::.ctor
=============================================================
含有Base
class Father
{
private int father_int;
private Double father_double;
public Father(int x)
{
this.father_int = x;
this.father_double = 1.1;
}
}
class Son : Father
{
private int son_int;
private double son_double;
public Son(int father_x):base(father_x)
{
this.son_int = 2;
this.son_double = 2.2;
}
}
//====== .ctor(int32) Father的自定义构造函数============
.method public hidebysig specialname rtspecialname
instance void .ctor(int32 x) cil managed
{
// 代码大小 32 (0x20)
.maxstack 8
IL_0000: ldarg.0
IL_0001: call instance void [mscorlib]System.Object::.ctor()
IL_0006: nop
IL_0007: nop
IL_0008: ldarg.0
IL_0009: ldarg.1
IL_000a: stfld int32 ConsoleTest.Father::father_int
IL_000f: ldarg.0
IL_0010: ldc.r8 1.1000000000000001
IL_0019: stfld float64 ConsoleTest.Father::father_double
IL_001e: nop
IL_001f: ret
} // end of method Father::.ctor
//====== .ctor(int 32) Son的自定义构造函数============
.method public hidebysig specialname rtspecialname
instance void .ctor(int32 father_x) cil managed
{
// 代码大小 33 (0x21)
.maxstack 8
IL_0000: ldarg.0
IL_0001: ldarg.1
IL_0002: call instance void ConsoleTest.Father::.ctor(int32)
IL_0007: nop
IL_0008: nop
IL_0009: ldarg.0
IL_000a: ldc.i4.2
IL_000b: stfld int32 ConsoleTest.Son::son_int
IL_0010: ldarg.0
IL_0011: ldc.r8 2.2000000000000002
IL_001a: stfld float64 ConsoleTest.Son::son_double
IL_001f: nop
IL_0020: ret
} // end of method Son::.ctor
=====================================================================
class Father
{
private int father_int;
private Double father_double;
public Father(int x)
{
this.father_int = x;
this.father_double = 1.1;
}
}
class Son : Father
{
private int son_int;
private double son_double;
public Son()
{
this.son_int = 2;
this.son_double = 2.2;
}
}
编译时候会报错误 Father是有参数构构造函数
=====================================================
三：构造函数调用构造函数
class Son
{
private int son_int=3;
private double son_double;
public Son()
{
this.son_int = 2;
//this.son_double = 2.2;
}
public Son(double son_double):this()
{
this.son_double =son_double;
}
}
=====.ctor()============================
.method public hidebysig specialname rtspecialname
instance void .ctor() cil managed
{
// 代码大小 24 (0x18)
.maxstack 8
IL_0000: ldarg.0
IL_0001: ldc.i4.3
IL_0002: stfld int32 ConsoleTest.Son::son_int
IL_0007: ldarg.0
IL_0008: call instance void [mscorlib]System.Object::.ctor()
IL_000d: nop
IL_000e: nop
IL_000f: ldarg.0
IL_0010: ldc.i4.2
IL_0011: stfld int32 ConsoleTest.Son::son_int
IL_0016: nop
IL_0017: ret
} // end of method Son::.ctor
=======.ctor(float64 )================
.method public hidebysig specialname rtspecialname
instance void .ctor(float64 son_double) cil managed
{
// 代码大小 17 (0x11)
.maxstack 8
IL_0000: ldarg.0
IL_0001: call instance void ConsoleTest.Son::.ctor()
IL_0006: nop
IL_0007: nop
IL_0008: ldarg.0
IL_0009: ldarg.1
IL_000a: stfld float64 ConsoleTest.Son::son_double
IL_000f: nop
IL_0010: ret
} // end of method Son::.ctor
=====================================================
四：结构体的构造函数
struct TestStruct
{
int struct_int;
double struct_double;
}
=============================================
//错误：结构中不能有实例字段初始值设定项
struct TestStruct
{
int struct_int=3;
double struct_double;
}
==============================================
//错误 ：结构不能包含显式的无参数构造函数
struct TestStruct
{
int struct_int;
double struct_double;
public TestStruct()
{
}
}
==============================================
//错误1 在控制离开构造函数之前，字段“ConsoleTest.TestStruct.struct_int”必须完全赋值
错误2 在控制离开构造函数之前，字段“ConsoleTest.TestStruct.struct_double”必须完全赋值
struct TestStruct
{
int struct_int;
double struct_double;
public TestStruct(int x,double y)
{
}
}
==============================================
OK
struct TestStruct
{
int struct_int;
double struct_double;
public TestStruct(int x,double y)
{
struct_double = y;
struct_int = x;
}
}
ok
struct TestStruct
{
int struct_int;
double struct_double;
public TestStruct(int x,double y)
{
struct_double = 3;
struct_int = x;
}
}
==.ctor(int32,float64)============
.method public hidebysig specialname rtspecialname
instance void .ctor(int32 x,
float64 y) cil managed
{
// 代码大小 24 (0x18)
.maxstack 8
IL_0000: nop
IL_0001: ldarg.0
IL_0002: ldc.r8 3.
IL_000b: stfld float64 ConsoleTest.TestStruct::struct_double
IL_0010: ldarg.0
IL_0011: ldarg.1
IL_0012: stfld int32 ConsoleTest.TestStruct::struct_int
IL_0017: ret
} // end of method TestStruct::.ctor