Question

在参考类别中,物体的记忆布局是

| Type Object pointer|
|    Sync Block      |
|  Instance fields...|

对价值类型而言,标的布局似乎是

|  Instance fields...|

就参考类型而言,GetType是指从类型目标点发现物体。特定参比物体的所有物体均指同一类型物体(也附有方法表)

就价值类型而言,该点码是可用的。因此,GetType()的工作如何?

我与谷歌进行了检查,我发现这片ni。是否有人阐述?

The solution is that the location in which a value is stored may only store values of a certain type. This is guaranteed by the verifier. Source

Answer 1

GetType(>>,贴上价值类型箱的数值。通过将价值类别移至微粒,现在有一个参考类型,现在该参考类别就是指该物体的类型。

如果你希望避免打箱,请打电话GetTypeCode,其中注明价值类型而无需箱子的点数。



这里的一个例子是,出现了下列插手:

<><>C#>:

class Program
{
    static void Main()
    {
        34.GetType();
    }
}

Main(:>

.method private hidebysig static void Main() cil managed
{
        .entrypoint
        .maxstack 8
        L_0000: ldc.i4.s 0x22
        L_0002: box int32
        L_0007: call instance class [mscorlib]System.Type [mscorlib]System.Object::GetType()
        L_000c: pop 
        L_000d: ret 
}

<><>Edit>: 为了显示汇编者正在做些什么,请将字面的类型改变为:

class Program
{
    static void Main()
    {
        34L.GetType();
    }
}

在字面之后添加<代码>L”<>,我告诉汇编者,我希望将字面改为<代码>System.Int64。汇编者看到这一点,在采用<编码> 方框<>代码/代码>指示时,其认为:

.method private hidebysig static void Main() cil managed
{
        .entrypoint
        .maxstack 8
        L_0000: ldc.i4.s 0x22
        L_0002: conv.i8 
        L_0003: box int64
        L_0008: call instance class [mscorlib]System.Type [mscorlib]System.Object::GetType()
        L_000d: pop 
        L_000e: ret 
}

各位可以看到,汇编者在由《刑法》委员会执行之后,为确定正确的发送指示做了艰苦的工作。

Answer 2

Maybe Andrew H.将这一点视为显而易见的,并试图使我理解+1,我的灯布时来自Joon Skeet(这是通过我所阅读的书本,也是在答案所在的确切地区周围)。

C# is a statically typed. Each variable has a type and it is known at compile time.
Value types can t be inherited. As a result, the VT objects don t need to carry around extra type information (as opposed to Ref Type objects, each of which have an object type header since the variable type and value/object type may differ.)

考虑如下文。虽然变型类型是“基地”,但还是指一种较为专业化的物体。对于价值类型而言,由于遗产被宣布为非法,因此物体类型为。

BaseRefType r = new DerivedRefType(); ValueType v = new ValueType();

My missing piece was bullet#1.
<Snipped after J.Skeet s comment since it seems to be wrong>. There seems to be some magic that lets the compiler/runtime know the type of the variable given any arbitrary variable. So the runtime somehow knows that ob is of MyStruct type, even though the VT object itself has no type information.

MyStruct ob = new MyStruct(); ob.WhoAmI(); // no box ; defined in MyStruct Console.WriteLine(ob.GetHashCode()); // no box ; overridden in ValueType Console.WriteLine( ob.GetType() ); // box ; implemented in Object

因此,我能够援引MyStruct(和价值Type(出于某种原因)所定义的方法,而没有插手RefType。

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