使用C#实现搜索继承类

C#频道 >

时间: 2008-05-27 21:29

有这样一个Control，它需要获得所有BaseType的继承类。由于BaseType的继承类可能存在于当前程序集或者被当前工程引用的其他程序集，所以需要动态搜索可能存在的所有继承类。
为完成该功能，我写了下面两个方法，记录下来，为以后使用。
1，这个方法使用了DesignTime下的ITypeDiscoveryService，可以在DesignTime下使用。不过VS2008以下的ITypeDiscoveryService实现逻辑有Bug，不会搜索baseType所在的程序集，所有需要先搜索baseType所在的程序集。

///<summary>

/// Discovers available derived types that derived from baseType at design time.

///</summary>

///<param name="host">

/// The <see cref="IDesignerHost"/>.

///</param>

///<param name="baseType">

/// The base type to match.

///</param>

///<param name="excludeGlobalTypes">

/// Indicates whether types from all referenced assemblies should be checked.

///</param>

///<returns>

/// A collection of types that derived from baseType.

///</returns>

public static Type[] GetDerivedTypes(IDesignerHost host, Type baseType, bool excludeGlobalTypes)

{

if (host == null)

{

throw new ArgumentNullException("host");

}

if (baseType == null)

{

throw new ArgumentNullException("baseType");

}

List<Type> derivedTypes = new List<Type>();

// Find derived types from base type's assembly.

if (!excludeGlobalTypes || !baseType.Assembly.GlobalAssemblyCache)

{

Type[] baseTypes = baseType.Assembly.GetTypes();

foreach (Type type in baseTypes)

{

if ((type.IsPublic || type.IsNestedPublic) && baseType.IsAssignableFrom(type))

{

derivedTypes.Add(type);

}

// Find derived types by ITypeDiscoveryService.

ITypeDiscoveryService service = host.GetService(typeof(ITypeDiscoveryService)) as ITypeDiscoveryService;

if (service != null)

{

ICollection discoveryTypes = service.GetTypes(baseType, excludeGlobalTypes);

foreach (Type type in discoveryTypes)

{

if (!derivedTypes.Contains(type))

{

derivedTypes.Add(type);

}

return derivedTypes.ToArray();

}

2，这个方法会搜索当前Domain中所有程序集，注意，继承类所在的程序集会引用baseType所在的程序集，利用这一点可以做一定程度的性能优化。

///<summary>

/// Discovers available derived types that derived from baseType from current domain.

///</summary>

///<param name="baseType">

/// The base type to match.

///</param>

///<param name="excludeGlobalTypes">

/// Indicates whether types from all referenced assemblies should be checked.

///</param>

///<returns>

/// A collection of types that derived from baseType.

///</returns>

public static Type[] GetDerivedTypes(Type baseType, bool excludeGlobalTypes)

{

if (baseType == null)

{

throw new ArgumentNullException("baseType");

}

List<Type> derivedTypes = new List<Type>();

AssemblyName baseAssemblyName = baseType.Assembly.GetName();

// Find derived types from CurrentDomain.

Assembly[] assemblys = AppDomain.CurrentDomain.GetAssemblies();

foreach (Assembly assembly in assemblys)

{

// Important, It can improve performance.

bool needSearch = false;

if (!excludeGlobalTypes || !assembly.GlobalAssemblyCache)

{

if (string.Equals(assembly.FullName, baseAssemblyName.FullName, StringComparison.OrdinalIgnoreCase))

{

needSearch = true;

}

else

{

AssemblyName[] referencedAssemblies = assembly.GetReferencedAssemblies();

foreach (AssemblyName assemblyName in referencedAssemblies)

{

if (string.Equals(assemblyName.FullName, baseAssemblyName.FullName, StringComparison.OrdinalIgnoreCase))

{

needSearch = true;

break;

}

if (needSearch)

{

Type[] types = assembly.GetTypes();

foreach (Type type in types)

{

if ((type.IsPublic || type.IsNestedPublic) && baseType.IsAssignableFrom(type) && !derivedTypes.Contains(type))

{

derivedTypes.Add(type);

}

return derivedTypes.ToArray();

}

1 / 1 页

跳转页

作者
admin

添加至收藏夹