ZT如何获取程序集内的类型

Posted on 2005-03-11 17:30 HAL9000 阅读(1185) 评论(0) 编辑收藏举报

如何获取程序集内的类型

本示例阐释如何检索给定程序集的所有类型。若要浏览程序集的类型，首先需要标识想操作的程序集。在使某对象引用了感兴趣的程序集后，可以在该程序集上调用 GetTypes 方法，它返回包含该程序集内所有类型的一个数组。您可以使用控制逻辑标识该数组中的更具体类型，并使用迭代逻辑分析您的数组，在需要时向用户返回类型信息。检索类型信息的功能对确定可用于给定任务的其他类型很有用，或对标识可为您提供所需功能的现有元素很有用。

C# GetTypes.aspx

[运行示例] | [查看源代码]

从特定程序集检索类型时要学习的首要内容是如何标识程序集。本"快速入门"展示检索程序集的两种方法。第一种方法是标识要在程序集内查找的特定对象，并向程序集请求该对象的模块（记住模块是类型和代码的逻辑分组，如 .dll 或 .exe）。第二种方法是使用 Assembly 类的 LoadFrom 方法，为指定模块（如 myapp.exe）加载特定程序集。

// don't forget your using statements
using System;
using System.Reflection;
// ...

// Getting an Assembly, method 1. Get the mscorlib assembly
// Note that other types such as String, or Int32 would have worked just as well,
// since they reside in the same assembly
Assembly a = typeof(Object).Module.Assembly;

// Getting an Assembly, method 2. Load a particular assembly, using a reference to a
// module that is within that assembly. Note that this requires a compiled module for
// the reference, and when running in an aspx page, will require a fully qualifed path
// to the file, to ensure it is correctly identified
Assembly b = Assembly.LoadFrom ("GetTypes.exe");

// note that either of the above methods is viable, depending on the information
// you have. Since we know the name of the file which houses all of the base system
// objects, we could do the following to replace the first example, just as effectively
// (the absolute path may change on your machine)
// Assembly a = Assembly.LoadFrom
//			("c:/winserv/microsoft.net/framework/v1.0.2230/mscorlib.dll");

'  don't forget your using statements
Imports System
Imports System.Reflection
' ...

'  Getting an Assembly, method 1. Get the mscorlib assembly
'  Note that other types such as String, or Int32 would have worked just as well,
'  since they reside in the same assembly
Dim a As reflection.Assembly = GetType(Object).Module.Assembly

'  Getting an Assembly, method 2. Load a particular assembly, using a reference to a
'  module that is within that assembly. Note that this requires a compiled module for
'  the reference, and when running in an aspx page, will require a fully qualifed path
'  to the file, to ensure it is correctly identified
Dim b As reflection.Assembly = reflection.Assembly.LoadFrom ("GetTypes.exe")

'  note that either of the above methods is viable, depending on the information
'  you have. Since we know the name of the file which houses all of the base system
'  objects, we could do the following to replace the first example, just as effectively
'  (the absolute path may change on your machine)
'  Dim a As reflection.Assembly = reflection.Assembly.LoadFrom _
'			("c:/winserv/microsoft.net/framework/v1.0.2230/mscorlib.dll")

标识了程序集后，现在可以继续检索类型，将 GetTypes 方法的返回值分配给 Type 对象的数组。现在便可以操作这些类型了。在下面的示例中，您将获取核心运行时库的类型，并分别计算该程序集内不同类型样式的数目（如果需要有关 Foreach (For Each) 语句的更多信息，请参阅如何迭代通过集合主题下的内容）。尽管还可以计算其他成员（如类和枚举）的数目，但在该示例中，将只展示如何计算接口数目。

//Get all the types in the assembly identified in the previous example
Type [] types = a.GetTypes ();

int numInterfaces = 0;



foreach (Type t in types) {

	//the following line uses a set of methods which identify what
	//kind of type we are currently querying
	if (t.IsInterface) {
		// only print out the names of the Interfaces
		Console.WriteLine (t.Name + "");
		numInterfaces++;
	}
}

// write out the totals
Console.WriteLine("Out of {0} types in the {1} library:",
			types.Length, typeof(Object).Module.ToString());
Console.WriteLine ("{0} are interfaces (listed)", types.Length, numInterfaces);

' Get all the types in the assembly identified in the previous example
Dim types() As Type = a.GetTypes ()

Dim numInterfaces As Integer = 0

Dim t As Type

For Each t in types

	' the following line uses a set of methods which identify what
	' kind of type we are currently querying
	If t.IsInterface Then
		'  only print out the names of the Interfaces
		Console.WriteLine (t.Name + "'")
		numInterfaces = numInterfaces + 1
	End If
Next t

'  write out the totals
Console.WriteLine("Out of {0} types in the {1} library:", _
			types.Length, GetType(Object).Module.ToString())
Console.WriteLine ("{0} are interfaces (listed)", types.Length, numInterfaces)

还可以使用第一个示例中标识的第二种方法检索给定程序集的类型。在下面的示例中，您将注意到它并未使用相同的基结构来依次通过类型，因为您不需要跟踪类型的不同种类。当查看小型程序集时这很适合，如当前运行的应用程序（获取 MSCorLib 的所有类型的列表将得到一个非常大的列表）。

// Get all the types in the assembly identified in the previous example (this assembly)
Type [] types2 = b.GetTypes ();

Console.WriteLine ("Get all the types from the assembly: '{0}'", b.GetName());

foreach (Type t in types2)
{
    Console.WriteLine (t.FullName);
}

'  Get all the types in the assembly identified in the previous example (this assembly)
Dim types2() As Type = b.GetTypes ()

Console.WriteLine ("Get all the types from the assembly: '{0}'", b.GetName())

For Each t in types2

	Console.WriteLine(t.FullName) ' not many types, so we can print them all
Next t