我在Winforms，C＃.NET4.5
工作我在程序集A中有一个名为classA的类，它提供了method1
在我的主程序中，我可以调用此方法，但在某些情况下，我100％肯定 这不可能因为注册表项中的一些内部标志而发生：
if( valueFromRegistryIsAlwaysFalse)
{
var A = new classA();
A.method1();
}
当我在注册表中设置此值时，我不想为程序集A提供主可执行文件，但是即使我不使用该方法，它也需要程序集A来启动。我当然得到了这个，但有没有办法绕过这个？
答案 0 :(得分：10)
通常，当CLI正在JITting任何包含尚未加载的程序集中的类型的包含方法时，程序集加载和聚合会按需发生。所以：“修复”的方法是将涉及此程序集中类型的所有代码移动到永远不会执行的方法中。例如：
if( valueFromRegistryIsAlwaysFalse)
{
DoStuff();
}
[System.Runtime.CompilerServices.MethodImpl(
System.Runtime.CompilerServices.MethodImplOptions.NoInlining)]
void DoStuff()
{
var A = new classA();
A.method1();
}
通过此更改，原始方法未提及classA，因此可以在不需要额外程序集的情况下对该方法进行JIT;因为DoStuff永远不会被执行/ JIT，所以它永远不会从那里加载。
答案 1 :(得分：1)
创建一个既调用者又调用classA的接口程序集。 删除引用并动态加载程序集并实例化该类。
Assembly asm = Assembly.LoadFile(@"C:\classAAssembly.dll");
Type type = asm.GetType("classA");
IClassA a = Activator.CreateInstance(type) as IClassA;
答案 2 :(得分：1)
我认为对于您的特定情况，您也可以使用MEF http://msdn.microsoft.com/en-us/library/dd460648.aspx
答案 3 :(得分：1)
通常，框架会按需加载程序集。不同的方法是使用动态载荷模式或复合模式。从框架4.0开始，MS引入了System.Addin命名空间来帮助程序员。我在我的项目中使用了以下类来实现与Framework 2.0兼容性相同的类：
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Globalization;
using System.IO;
using System.Reflection;
namespace MyNamespace
{
[Serializable]
public enum CompositeLoaderFilter
{
ImplementsInterface = 0,
InheritsBaseClass = 1
}
[Serializable]
public static class Composite
{
private static readonly CompositeManager manager = new CompositeManager();
public static CompositeManager Manager { get { return manager; } }
}
[Serializable]
public class CompositeManager : MarshalByRefObject
{
private SortedList<string, Type> m_addIns;
public int GetInMemoryComponents(Type addInType, CompositeLoaderFilter filter)
{
m_addIns = internal_GetInMemoryServices(addInType, filter);
return m_addIns.Count;
}
public int GetComponents(Type addInType, CompositeLoaderFilter filter)
{
string addInPath = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
return GetComponents(addInPath, "*.dll", SearchOption.TopDirectoryOnly, addInType, filter);
}
public int GetComponents(string addInSearchPattern, Type addInType, CompositeLoaderFilter filter)
{
string addInPath = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
return GetComponents(addInPath, addInSearchPattern, SearchOption.TopDirectoryOnly, addInType, filter);
}
public int GetComponents(string addInPath, string addInSearchPattern, Type addInType, CompositeLoaderFilter filter)
{
return GetComponents(addInPath, addInSearchPattern, SearchOption.TopDirectoryOnly, addInType, filter);
}
public int GetComponents(string addInPath, string addInSearchPattern, SearchOption addInSearchOption, Type addInType, CompositeLoaderFilter filter)
{
AppDomainSetup setup = AppDomain.CurrentDomain.SetupInformation;
setup.PrivateBinPath = addInPath;
setup.ShadowCopyFiles = "false";
AppDomain m_appDomain = AppDomain.CreateDomain("MyNamespace.CompositeManager", null, setup);
CompositeManager m_remoteLoader = (CompositeManager)m_appDomain.CreateInstanceFromAndUnwrap(Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "MyAssembly.dll"), "MyNamespace.CompositeManager");
m_addIns = m_remoteLoader.RemoteGetServices(addInPath, addInSearchPattern, addInSearchOption, addInType, filter);
#if DEBUG
DebugLoadedAssemblies();
#endif
AppDomain.Unload(m_appDomain);
return m_addIns.Count;
}
public object CreateInstance(string typeName)
{
if (!m_addIns.ContainsKey(typeName))
throw new ArgumentException(string.Format(CultureInfo.CurrentCulture, "Type {0} was not loaded..", typeName), "typeName");
MethodInfo method = m_addIns[typeName].GetMethod("GetInstance", BindingFlags.Static | BindingFlags.Public | BindingFlags.Instance | BindingFlags.FlattenHierarchy);
if (method != null)
return method.Invoke(m_addIns[typeName], null);
else return Activator.CreateInstance(m_addIns[typeName]);
}
public object CreateInstance(Type type)
{
if (type == null)
throw new ArgumentNullException("type", "Type is null");
if (!m_addIns.ContainsKey(type.FullName))
throw new ArgumentException(string.Format(CultureInfo.CurrentCulture, "Type {0} was not loaded..", type.FullName), "type");
MethodInfo method = type.GetMethod("GetInstance", BindingFlags.Static | BindingFlags.Public | BindingFlags.Instance | BindingFlags.FlattenHierarchy);
if (method != null)
return method.Invoke(type, null);
else return Activator.CreateInstance(type);
}
public T CreateInstance<T>()
{
if (!m_addIns.ContainsKey(typeof(T).FullName))
throw new ArgumentException(string.Format(CultureInfo.CurrentCulture, "Type {0} was not loaded..", typeof(T).FullName), "T");
MethodInfo method = typeof(T).GetMethod("GetInstance", BindingFlags.Static | BindingFlags.Public | BindingFlags.Instance | BindingFlags.FlattenHierarchy);
if (method != null)
return (T)method.Invoke(typeof(T), null);
else return Activator.CreateInstance<T>();
}
public IEnumerable<Type> AvailableServices
{
get
{
foreach (KeyValuePair<string, Type> item in m_addIns)
{
yield return item.Value;
}
}
}
public Type[] AvailableTypes
{
get
{
List<Type> list = new List<Type>();
foreach (KeyValuePair<string, Type> item in m_addIns)
list.Add(item.Value);
return list.ToArray();
}
}
public T[] GetObjects<T>()
{
List<T> list = new List<T>();
foreach (KeyValuePair<string, Type> item in m_addIns)
list.Add((T)CreateInstance(item.Value));
return list.ToArray();
}
public object[] AvailableObjects
{
get
{
List<object> list = new List<object>();
foreach (KeyValuePair<string, Type> item in m_addIns)
list.Add(CreateInstance(item.Value));
return list.ToArray();
}
}
internal SortedList<string, Type> internal_GetInMemoryServices(Type addInType, CompositeLoaderFilter filter)
{
SortedList<string, Type> validAddIns = new SortedList<string, Type>();
Assembly[] assemblies = AppDomain.CurrentDomain.GetAssemblies();
foreach (Assembly assembly in assemblies)
{
try
{
Type[] types = assembly.GetTypes();
foreach (Type type in types)
{
switch (filter)
{
case CompositeLoaderFilter.ImplementsInterface:
if (type.GetInterface(addInType.Name) != null)
validAddIns.Add(type.FullName, type);
break;
case CompositeLoaderFilter.InheritsBaseClass:
if (type.BaseType == addInType)
validAddIns.Add(type.FullName, type);
break;
}
}
}
catch (FileLoadException flex)
{
Debug.WriteLine(string.Format(CultureInfo.CurrentCulture, "{0} MyNamespace.CompositeManager: {1}", DateTime.Now.ToString(), flex.Message));
}
catch (Exception ex)
{
Debug.WriteLine(string.Format(CultureInfo.CurrentCulture, "{0} MyNamespace.CompositeManager: {1}", DateTime.Now.ToString(), ex.Message));
}
}
return validAddIns;
}
internal SortedList<string, Type> RemoteGetServices(string addInPath, string addInSearchPattern, SearchOption addInSearchOption, Type addInType, CompositeLoaderFilter filter)
{
string[] files = Directory.GetFiles(addInPath, addInSearchPattern, addInSearchOption);
SortedList<string, Type> validAddIns = new SortedList<string, Type>();
if (files.Length > 0)
{
foreach (string file in files)
{
if (String.CompareOrdinal(addInPath, file) != 0)
{
try
{
Assembly assembly = Assembly.LoadFrom(file);
Type[] types = assembly.GetTypes();
foreach (Type type in types)
{
switch (filter)
{
case CompositeLoaderFilter.ImplementsInterface:
if (type.GetInterface(addInType.Name) != null)
validAddIns.Add(type.FullName, type);
break;
case CompositeLoaderFilter.InheritsBaseClass:
if (type.BaseType == addInType)
validAddIns.Add(type.FullName, type);
break;
}
}
}
catch (FileLoadException flex)
{
Debug.WriteLine(string.Format(CultureInfo.CurrentCulture, "{0} MyNamespace.CompositeManager: {1}", DateTime.Now.ToString(), flex.Message));
}
catch (Exception ex)
{
Debug.WriteLine(string.Format(CultureInfo.CurrentCulture, "{0} MyNamespace.CompositeManager: {1}", DateTime.Now.ToString(), ex.Message));
}
}
}
}
#if DEBUG
DebugLoadedAssemblies();
#endif
return validAddIns;
}
#if DEBUG
internal void DebugLoadedAssemblies()
{
foreach (Assembly a in AppDomain.CurrentDomain.GetAssemblies())
{
//Debug.WriteLine(string.Format("Domain: {0} Assembly: {1}", AppDomain.CurrentDomain.FriendlyName, a.FullName));
}
}
#endif
}
}
使用示例后：
Composite.Manager.GetComponents(typeof(IMyService), CompositeLoaderFilter.ImplementsInterface);
IMyService[] services = Composite.Manager.GetObjects<IMyService>();
该类将加载当前文件夹中的所有程序集，检查它们以查看它们是否包含与输入参数匹配的Type。因为加载后无法卸载程序集，所以该类会将它们加载到不同的AppDomain中，与单个程序集相反，它可以被删除。
要在项目中使用它，您应按以下步骤操作：
希望有所帮助：）