Type.FindInterfaces(TypeFilter，Object)方法用于返回Type对象的数组，该数组表示由当前Type实现或继承的接口的过滤列表。在搜索过程中，将考虑由此类实现的所有接口，无论是由基类声明还是由此类本身声明。
此方法搜索基类层次结构，返回每个类实现的每个匹配接口以及每个接口实现的所有匹配接口(即，返回匹配接口的可传递闭包)。没有返回重复的接口。
句法：
public virtual Type[] FindInterfaces (System.Reflection.TypeFilter filter, object filterCriteria);
参数：
- filter ：将接口与filterCriteria进行比较的委托。
- filterCriteria ：确定是否应该在返回的数组中包含接口的搜索条件。
返回值：该方法返回一个Type对象数组，该数组表示由当前Type实现或继承的接口的过滤列表；如果当前Type没有实现或继承与该过滤器匹配的接口，则返回一个Type类型的空数组。
异常：如果filter为null，则此方法将引发ArgumentNullException。
下面的程序说明了上述方法的用法：
范例1：
// C# program to demonstrate the
// Type.FindInterfaces(TypeFilter,
// Object) Method
using System;
using System.Globalization;
using System.Reflection;
class GFG {
// Main Method
public static void Main()
{
// Creating try-catch block
// to handle exceptions
try {
// Declaring and initializing
// object Type Datatype
Type type = typeof(System.String);
// Declaring and initializing the object
// of TypeFilter Datatype which help the
// delegate that compares the interfaces
// against filterCriteria
TypeFilter myFilter = new TypeFilter(MyInterfaceFilter);
// Declaring and initializing filterCriteria
// object. It is used to search the criteria
// that determines whether an interface should
// be included in the returned array.
object filterCriteria = "System.Collections.IEnumerable";
// Getting the filtered list of interface
// using FindInterfaces() method
Type[] myInterfaces = type.FindInterfaces(myFilter,
filterCriteria);
// Display the interfaces
for (int j = 0; j < myInterfaces.Length; j++)
Console.WriteLine("filtered list of interface : {0}.",
myInterfaces[j].ToString());
}
// catch ArgumentNullException here
catch (ArgumentNullException e)
{
Console.Write("Exception Thrown: ");
Console.Write("{0}", e.GetType(), e.Message);
}
}
// Defining MyInterfaceFilter
// which helps to fix the certain
// condition on which filtration
// took place
public static bool MyInterfaceFilter(Type typeObj,
Object criteriaObj)
{
if (typeObj.ToString() == criteriaObj.ToString())
return true;
else
return false;
}
}
输出：
filtered list of interface : System.Collections.IEnumerable.
范例2：
// C# program to demonstrate the
// Type.FindInterfaces(TypeFilter,
// Object) Method
using System;
using System.Globalization;
using System.Reflection;
class GFG {
// Main Method
public static void Main()
{
// Creating try-catch block
// to handle exceptions
try {
// Declaring and initializing
// object Type Datatype
Type type = typeof(System.String);
// Declaring and initializing object
// of TypeFilter Datatype
// which help the delegate that compares
// the interfaces against filterCriteria.
TypeFilter myFilter = null;
// Declaring and initializing filterCriteria
// object. It is used to search the criteria
// that determines whether an interface should
// be included in the returned array.
object filterCriteria = "System.Collections.IEnumerable";
// Getting the filtered list of interface
// using FindInterfaces() method
Type[] myInterfaces = type.FindInterfaces(myFilter,
filterCriteria);
// Display the interfaces
for (int j = 0; j < myInterfaces.Length; j++)
Console.WriteLine("filtered list of interface : {0}.",
myInterfaces[j].ToString());
}
// catch ArgumentNullException here
catch (ArgumentNullException e)
{
Console.WriteLine("myFilter should not be null");
Console.Write("Exception Thrown: ");
Console.Write("{0}", e.GetType(), e.Message);
}
}
}
输出：
myFilter should not be null
Exception Thrown: System.ArgumentNullException
参考：
- https://docs.microsoft.com/zh-cn/dotnet/api/system.type.findinterfaces?view=netcore-3.0