blocks|key|1583537|text|因此，地图方法的工作实现：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1583538|common+map(source+obj)
{
++++var+typeOfObj+=+obj.GetType().GetFields(
++++++++BindingFlags.Public+%7C
++++++++BindingFlags.NonPublic+%7C
++++++++BindingFlags.Instance)
++++++++.First(fi=>fi.Name+==+"obj");
++++return+(common)+Activator.CreateInstance(typeOfObj.FieldType);
}|code-block|syntax|javascript|1583539|归档的如果您需要obj.obj的get类型，那么您可以使用：|offset|length|style|BOLD|CODE|1583540|void+map(source+obj){
+++obj.obj.GetType()+...
}|1583541|但是，由于还没有实例化它，所以需要反射：|1583542|var+f+=+typeof(source).GetField("obj");
f.FieldType+//+contains+expected|1583543|如果私有字段是一个问题，则必须通过以下方法解决所有字段数组的迭代：|1583544|FieldInfo[]+fields+=+source.GetFields(
+++++++++++++++++++++BindingFlags.NonPublic+%7C+
+++++++++++++++++++++BindingFlags.Instance);|1583545|并定位名为"obj"的字段|1583546|entityMap^0|0|0|0|3|8|7|0|0|0|0|0|0|5|5|0^^$0|@$1|2|3|4|5|6|7|11|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|12|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|13|8|@$I|14|J|15|K|L]|$I|16|J|17|K|M]]|9|@]|A|$]]|$1|N|3|O|5|D|7|18|8|@]|9|@]|A|$E|F]]|$1|P|3|Q|5|6|7|19|8|@]|9|@]|A|$]]|$1|R|3|S|5|D|7|1A|8|@]|9|@]|A|$E|F]]|$1|T|3|U|5|6|7|1B|8|@]|9|@]|A|$]]|$1|V|3|W|5|D|7|1C|8|@]|9|@]|A|$E|F]]|$1|X|3|Y|5|6|7|1D|8|@$I|1E|J|1F|K|M]]|9|@]|A|$]]|$1|Z|3|-4|5|6|7|1G|8|@]|9|@]|A|$]]]|10|$]]

So working implementation of map method:

<pre><code>common map(source obj)
{
 var typeOfObj = obj.GetType().GetFields(
 BindingFlags.Public |
 BindingFlags.NonPublic |
 BindingFlags.Instance)
 .First(fi=&gt;fi.Name == "obj");
 return (common) Activator.CreateInstance(typeOfObj.FieldType);
}
</code></pre>

ARCHIVED
If you need get type for <code>obj.obj</code> then you have use:

<pre><code>void map(source obj){
 obj.obj.GetType() ...
}
</code></pre>

But since you have not instantiate it yet then you need reflection:

<pre><code>var f = typeof(source).GetField("obj");
f.FieldType // contains expected
</code></pre>

If private field is a problem then you have to iterate by all array of fields resolved by:

<pre><code>FieldInfo[] fields = source.GetFields(
 BindingFlags.NonPublic | 
 BindingFlags.Instance);
</code></pre>

And locate field named <code>"obj"</code>

blocks|key|552759|text|如果要实例化接收到的类，可以使用Activator：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|552760|Activator.CreateInstance(obj.obj.GetType());|code-block|syntax|javascript|552761|虽然我不知道你想达到什么目的。|552762|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

And if you want to instantiate your received class you can use Activator:

<pre><code>Activator.CreateInstance(obj.obj.GetType());
</code></pre>

Although I'm not sure what you are trying to achieve.

blocks|key|1583604|text|这个问题在哪里？不需要反思：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1583605|void+map(source+obj)
{
++++obj.obj+=+new+common();
}|code-block|syntax|javascript|1583606|基本上，您可以随意修改任何传递的对象，在您的方法中唯一不能做的就是将obj设置为需要ref-keyword的新的source实例。在您的例子中，您知道传递的对象的类型，所以我猜您也知道your类的组成，因此也知道obj-property的类型。|offset|length|style|CODE|1583607|entityMap^0|0|0|Y|3|16|3|1K|6|2Y|3|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]|$I|T|J|U|K|L]|$I|V|J|W|K|L]|$I|X|J|Y|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|N|$]]

Where is the problem on this? No need for reflection:

<pre><code>void map(source obj)
{
 obj.obj = new common();
}
</code></pre>

Basically you can modify any passed object as you want, the only thing you can´t do within your method is to set <code>obj</code> to a new instance of <code>source</code> for which you´d need the <code>ref</code>-keyword. In your case you know the type of the passed object, so I guess you also know what the concerning class consists of and thus the type for the <code>obj</code>-property.

blocks|key|555804|text|如果我错了，请纠正我的理解。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|555805|一旦实例化了common对象，就需要实例化内部source对象。如果是这样的话，您可以在您的constructor中编写一个source，它将实例化您的私有common对象。像这样的东西|offset|length|style|CODE|555806|class+source
{+
++++common+obj;
++++public+source()
++++{
++++++++obj+=+new+common();
++++}

}|code-block|syntax|javascript|555807|entityMap^0|0|6|6|N|6|1A|B|1Q|6|26|6|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@$D|Q|E|R|F|G]|$D|S|E|T|F|G]|$D|U|E|V|F|G]|$D|W|E|X|F|G]|$D|Y|E|Z|F|G]]|9|@]|A|$]]|$1|H|3|I|5|J|7|10|8|@]|9|@]|A|$K|L]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|A|$]]]|N|$]]

correct my understanding if I am wrong.

you want to instantiate the inner <code>common</code> object once you instantiated the <code>source</code> object. if so you could write an <code>constructor</code> inside your <code>source</code> which will instantiate your private <code>common</code> object. something like this

<pre><code>class source
{ 
 common obj;
 public source()
 {
 obj = new common();
 }

}
</code></pre>

blocks|key|552793|text|从输入对象获取类型字段信息，然后实例化该字段类型的对象，并将值设置为输入对象：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|552794|//+Get+field+info+for+source.obj
FieldInfo+fieldInfo+=+obj.GetType().GetField("obj",+BindingFlags.NonPublic+%7C+BindingFlags.Instance+%7C+BindingFlags.Public);
//+Instantiate+object+without+initializing+it
object+instance+=+FormatterServices.GetUninitializedObject(fieldInfo.FieldType);
//+set+instantiated+object+reference+to+the+field+source.obj
fieldInfo.SetValue(obj,+instance);|code-block|syntax|javascript|552795|如果您正在制作"AutoMapper“，那么这将满足您的需要，因为它不使用构造函数，而在其他答案中，构造函数应该是默认的(无参数的)构造函数。|552796|这里+--您可以比较不同的对象实例化方法，而不需要默认(无参数)构造函数。|offset|length|552797|将递归映射的完整代码示例：|552798|public+static+void+Main()
{
++++_genericMapInfo+=+typeof(Program).GetMethod("map",+BindingFlags.NonPublic+%7C+BindingFlags.Static);
++++Test+t+=+null;
++++map(ref+t);
++++Console.WriteLine(t+==+null);+//+False
++++Console.WriteLine(t.A);+//+Hello+World!
++++Console.WriteLine(t.B.A);+//+1337
++++Console.WriteLine(t.B.B);+//+Hello+World!
}

static+MethodInfo+_genericMapInfo;

static+void+map<T>(ref+T+obj)
++++where+T+:+class
{
++++if(obj+==+null)
++++++++obj+=+(T)FormatterServices.GetUninitializedObject(typeof(T));

++++foreach(FieldInfo+fInfo+in+typeof(T).GetFields(BindingFlags.Instance+%7C+BindingFlags.NonPublic+%7C+BindingFlags.Public))
++++{
++++++++Type+fieldType+=+fInfo.FieldType;+++
++++++++TypeCode+tCode+=+Type.GetTypeCode(fInfo.FieldType);
++++++++if(tCode+==+TypeCode.Object)
++++++++{
++++++++++++object[]+param+=+new+object[]+{+fInfo.GetValue(obj)+};
++++++++++++_genericMapInfo.MakeGenericMethod(fieldType).Invoke(null,+param);
++++++++++++fInfo.SetValue(obj,+param[0]);
++++++++}
++++++++else+if(tCode+==+TypeCode.String)
++++++++{
++++++++++++fInfo.SetValue(obj,+"Hello+World!");++++
++++++++}
++++++++else+if(tCode+==+TypeCode.Int32)
++++++++{
++++++++++++fInfo.SetValue(obj,+1337);++
++++++++}

++++}
}

public+class+Test
{
++++public+string+A+{+get;+set;+}+++
++++public+TestInside+B+{+get;+private+set;+}

++++public+Test()
++++{
++++++++A+=+"no+siema";+
++++}
}

public+class+TestInside
{
++++public+int+A+{+get;+private+set;+}
++++public+string+B+{+get;+set;+}+++

++++public+TestInside(int+_someInteger)
++++{
++++++++A+=+_someInteger;+++
++++}
}|552799|在线检查|552800|entityMap|0|LINK|mutability|MUTABLE|url|https://dotnetfiddle.net/oTUtIE|1|http://www.tutorialspoint.com/compile_csharp_online.php?PID=0Bw_CjBb95KQMUS1hRnhxRHc0TkU^0|0|0|0|0|2|0|0|0|0|0|4|1|0^^$0|@$1|2|3|4|5|6|7|12|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|13|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|14|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|15|8|@]|9|@$K|16|L|17|1|18]]|A|$]]|$1|M|3|N|5|6|7|19|8|@]|9|@]|A|$]]|$1|O|3|P|5|D|7|1A|8|@]|9|@]|A|$E|F]]|$1|Q|3|R|5|6|7|1B|8|@]|9|@$K|1C|L|1D|1|1E]]|A|$]]|$1|S|3|-4|5|6|7|1F|8|@]|9|@]|A|$]]]|T|$U|$5|V|W|X|A|$Y|Z]]|10|$5|V|W|X|A|$Y|11]]]]

Get type field info from your input object then instantiate the object of that field's type and set the value back to your input object :

<pre><code>// Get field info for source.obj
FieldInfo fieldInfo = obj.GetType().GetField("obj", BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Public);
// Instantiate object without initializing it
object instance = FormatterServices.GetUninitializedObject(fieldInfo.FieldType);
// set instantiated object reference to the field source.obj
fieldInfo.SetValue(obj, instance);
</code></pre>

If you're making "AutoMapper" then this will fit your needs because it doesnt use constructor which in other answers should be the default ( parameterless ) one.

<a href="https://dotnetfiddle.net/oTUtIE" rel="nofollow noreferrer">Here</a> you can compare different methods of instantiating object without default ( parameterless ) constructor.

Full code example that will map recursively :

<pre><code>public static void Main()
{
 _genericMapInfo = typeof(Program).GetMethod("map", BindingFlags.NonPublic | BindingFlags.Static);
 Test t = null;
 map(ref t);
 Console.WriteLine(t == null); // False
 Console.WriteLine(t.A); // Hello World!
 Console.WriteLine(t.B.A); // 1337
 Console.WriteLine(t.B.B); // Hello World!
}

static MethodInfo _genericMapInfo;

static void map&lt;T&gt;(ref T obj)
 where T : class
{
 if(obj == null)
 obj = (T)FormatterServices.GetUninitializedObject(typeof(T));

 foreach(FieldInfo fInfo in typeof(T).GetFields(BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public))
 {
 Type fieldType = fInfo.FieldType; 
 TypeCode tCode = Type.GetTypeCode(fInfo.FieldType);
 if(tCode == TypeCode.Object)
 {
 object[] param = new object[] { fInfo.GetValue(obj) };
 _genericMapInfo.MakeGenericMethod(fieldType).Invoke(null, param);
 fInfo.SetValue(obj, param[0]);
 }
 else if(tCode == TypeCode.String)
 {
 fInfo.SetValue(obj, "Hello World!"); 
 }
 else if(tCode == TypeCode.Int32)
 {
 fInfo.SetValue(obj, 1337); 
 }

 }
}

public class Test
{
 public string A { get; set; } 
 public TestInside B { get; private set; }

 public Test()
 {
 A = "no siema"; 
 }
}

public class TestInside
{
 public int A { get; private set; }
 public string B { get; set; } 

 public TestInside(int _someInteger)
 {
 A = _someInteger; 
 }
}
</code></pre>

<a href="http://www.tutorialspoint.com/compile_csharp_online.php?PID=0Bw_CjBb95KQMUS1hRnhxRHc0TkU" rel="nofollow noreferrer">Online check</a>

blocks|key|552814|text|我们可以通过|type|unstyled|depth|inlineStyleRanges|entityRanges|data|552815|.GetType()|code-block|syntax|javascript|552816|方法，但当然我的情况不同，因为我将所有字段存储在|552817|FieldInfo[]|552818|所以我用|552819|FieldInfo.FieldType|552820|得到我的对象的类型。一旦我们有了对象类型的，我们就可以使用|offset|length|style|BOLD|552821|Activator.CreateInstance(Class+Type);|552822|若要创建类实例，请执行以下操作。|552823|entityMap^0|0|0|0|0|0|0|I|3|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|11|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|12|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|13|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|14|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|15|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|16|8|@$Q|17|R|18|S|T]]|9|@]|A|$]]|$1|U|3|V|5|D|7|19|8|@]|9|@]|A|$E|F]]|$1|W|3|X|5|6|7|1A|8|@]|9|@]|A|$]]|$1|Y|3|-4|5|6|7|1B|8|@]|9|@]|A|$]]]|Z|$]]

we can get the type by using 

<pre><code>.GetType()
</code></pre>

method but ofcourse my case is different since i stored all fields in

<pre><code>FieldInfo[]
</code></pre>

so i used

<pre><code>FieldInfo.FieldType
</code></pre>

to get the type of my object.
 Once we had our object type we can use

<pre><code>Activator.CreateInstance(Class Type);
</code></pre>

to create the instance of class.

I am implementing an auto mapper and stuck at this kind of scenario:

<ol>
<li>There is object of class <code>common</code> inside the object of class <code>source</code> which is just declared but not instantiated</li>
<li>when i pass the object of class <code>source</code> to a method map of <code>program</code> class</li>
</ol>

how can i get type of inner object(common class object) and instantiate it?

<pre><code>public class common
{
 public int x;
}

public class source
{
 public common obj;
}

class program
{
 static void main()
 {
 source obj = new source();
 map(obj);
 }

 void map(source obj)
 {
 **how can i get type of inner object class and instantiate it**
 }
}
</code></pre>

i used Type.GetType() but is giving empty.

can we instantiate an object of a class just declared and passed to a method in another class

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我正在实现一个自动映射器，并坚持这种情况：类common的对象在类source的对象中，该对象是刚刚声明的，但没有实例化。当我将类source的对象传递给program类的方法映射时如何获得内部对象(公共类对象)的类型并实例化它？public class common{    public int x;}public ...

问我们能否实例化刚刚声明的类的对象并传递给另一个类中的方法？
EN

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问我们能否实例化刚刚声明的类的对象并传递给另一个类中的方法？
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