Skip to main content
.NET Framework Class Library
Type..::.FindInterfaces Method

Returns an array of Type objects representing a filtered list of interfaces implemented or inherited by the current Type.

Namespace: System
Assembly: mscorlib (in mscorlib.dll)
Syntax
Public Overridable Function FindInterfaces ( _
	filter As TypeFilter, _
	filterCriteria As Object _
) As Type()
public virtual Type[] FindInterfaces(
	TypeFilter filter,
	Object filterCriteria
)
public:
virtual array<Type^>^ FindInterfaces(
	TypeFilter^ filter, 
	Object^ filterCriteria
)
abstract FindInterfaces : 
        filter:TypeFilter * 
        filterCriteria:Object -> Type[] 
override FindInterfaces : 
        filter:TypeFilter * 
        filterCriteria:Object -> Type[] 

Parameters

filter
Type: System.Reflection..::.TypeFilter
The delegate that compares the interfaces against filterCriteria.
filterCriteria
Type: System..::.Object
The search criteria that determines whether an interface should be included in the returned array.

Return Value

Type: array<System..::.Type>[]()[]
An array of Type objects representing a filtered list of the interfaces implemented or inherited by the current Type, or an empty array of type Type if no interfaces matching the filter are implemented or inherited by the current Type.

Implements

_Type..::.FindInterfaces(TypeFilter, Object)
Exceptions
ExceptionCondition
ArgumentNullException

filter is nullNothingnullptra null reference (Nothing in Visual Basic).

TargetInvocationException

A static initializer is invoked and throws an exception.

Remarks

This method can be overridden by a derived class.

The Module..::.FilterTypeName and Module..::.FilterTypeNameIgnoreCase delegates supplied by the System.Reflection..::.Module class may also be used, in lieu of the System.Reflection..::.TypeFilter delegate.

All of the interfaces implemented by this class are considered during the search, whether declared by a base class or this class itself.

This method searches the base class hierarchy, returning each of the matching interfaces each class implements as well as all the matching interfaces each of those interfaces implements (that is, the transitive closure of the matching interfaces is returned). No duplicate interfaces are returned.

If the current Type represents a type parameter in the definition of a generic type or generic method, FindInterfaces searches all the interfaces declared in the constraints on the type parameter, and all interfaces inherited through the interfaces declared in the constraints. If the current Type represents a type argument of a generic type, FindInterfaces searches all the interfaces implemented by the type, whether or not they match constraints.

NoteNote

FindInterfaces can return generic interfaces, even on types that are not generic. For example, a nongeneric type might implement IEnumerable<int> (IEnumerable(Of Integer) in Visual Basic).

Examples

The following example finds the specified interface implemented or inherited by the specified type, and then displays the interface names.



Imports System
Imports System.Xml
Imports System.Reflection
Imports Microsoft.VisualBasic

Public Class MyFindInterfacesSample
    Public Shared Sub Main()
        Try
            Dim myXMLDoc As New XmlDocument()
            myXMLDoc.LoadXml("<book genre='novel' ISBN='1-861001-57-5'>" _
                & "<title>Pride And Prejudice</title>" & "</book>")
            Dim myType As Type = myXMLDoc.GetType()

            ' Specify the TypeFilter delegate that compares the 
            ' interfaces against filter criteria.
            Dim myFilter As New TypeFilter(AddressOf MyInterfaceFilter)
            Dim myInterfaceList() As String = _
                {"System.Collections.IEnumerable", _
                "System.Collections.ICollection"}
            Dim index As Integer
            For index = 0 To myInterfaceList.Length - 1
                Dim myInterfaces As Type() = _
                    myType.FindInterfaces(myFilter, myInterfaceList(index))
                If myInterfaces.Length > 0 Then
                    Console.WriteLine(ControlChars.Cr & _
                        "{0} implements the interface {1}.", _
                        myType, myInterfaceList(index))
                    Dim j As Integer
                    For j = 0 To myInterfaces.Length - 1
                        Console.WriteLine("Interfaces supported: {0}", _
                            myInterfaces(j).ToString())
                    Next j
                Else
                    Console.WriteLine(ControlChars.Cr & _
                        "{0} does not implement the interface {1}.", _
                        myType, myInterfaceList(index))
                End If
            Next index
        Catch e As ArgumentNullException
            Console.WriteLine("ArgumentNullException: " & e.Message)
        Catch e As TargetInvocationException
            Console.WriteLine("TargetInvocationException: " & e.Message)
        Catch e As Exception
            Console.WriteLine("Exception: " & e.Message)
        End Try
    End Sub 'Main
    Public Shared Function MyInterfaceFilter(ByVal typeObj As Type, _
        ByVal criteriaObj As [Object]) As Boolean
        If typeObj.ToString() = criteriaObj.ToString() Then
            Return True
        Else
            Return False
        End If
    End Function 'MyInterfaceFilter 
End Class 'MyFindInterfacesSample


using System;
using System.Xml;
using System.Reflection;

public class MyFindInterfacesSample 
{
    public static void Main()
    {
        try
        {
            XmlDocument myXMLDoc = new XmlDocument();
            myXMLDoc.LoadXml("<book genre='novel' ISBN='1-861001-57-5'>" +
                "<title>Pride And Prejudice</title>" + "</book>");
            Type myType = myXMLDoc.GetType();

            // Specify the TypeFilter delegate that compares the 
            // interfaces against filter criteria.
            TypeFilter myFilter = new TypeFilter(MyInterfaceFilter);
            String[] myInterfaceList = new String[2] 
                {"System.Collections.IEnumerable", 
                "System.Collections.ICollection"};
            for(int index=0; index < myInterfaceList.Length; index++)
            {
                Type[] myInterfaces = myType.FindInterfaces(myFilter, 
                    myInterfaceList[index]);
                if (myInterfaces.Length > 0) 
                {
                    Console.WriteLine("\n{0} implements the interface {1}.",
                        myType, myInterfaceList[index]);	
                    for(int j =0;j < myInterfaces.Length;j++)
                        Console.WriteLine("Interfaces supported: {0}.", 
                            myInterfaces[j].ToString());
                }
                else
                    Console.WriteLine(
                        "\n{0} does not implement the interface {1}.", 
                        myType,myInterfaceList[index]);	
            }
        }
        catch(ArgumentNullException e)
        {
            Console.WriteLine("ArgumentNullException: " + e.Message);
        }
        catch(TargetInvocationException e)
        {
            Console.WriteLine("TargetInvocationException: " + e.Message);
        }
        catch(Exception e)
        {
            Console.WriteLine("Exception: " + e.Message);
        }
    }

    public static bool MyInterfaceFilter(Type typeObj,Object criteriaObj)
    {
        if(typeObj.ToString() == criteriaObj.ToString())
            return true;
        else
            return false;
    }
}


#using <system.xml.dll>

using namespace System;
using namespace System::Xml;
using namespace System::Reflection;
public ref class MyFindInterfacesSample
{
public:
    static bool MyInterfaceFilter(Type^ typeObj, Object^ criteriaObj)
    {
        if(typeObj->ToString()->Equals(criteriaObj->ToString()))
            return true;
        else
            return false;
   }
};

int main()
{
    try
    {
        XmlDocument^ myXMLDoc = gcnew XmlDocument;
        myXMLDoc->LoadXml("<book genre='novel' ISBN='1-861001-57-5'>" 
            + "<title>Pride And Prejudice</title> </book>");
        Type^ myType = myXMLDoc->GetType();

        // Specify the TypeFilter delegate that compares the interfaces 
        // against filter criteria.
        TypeFilter^ myFilter = gcnew TypeFilter( 
            MyFindInterfacesSample::MyInterfaceFilter);
        array<String^>^myInterfaceList = {"System.Collections.IEnumerable",
            "System.Collections.ICollection"};
        for(int index = 0; index < myInterfaceList->Length; index++)
        {
            array<Type^>^myInterfaces = myType->FindInterfaces( 
                myFilter, myInterfaceList[index]);
            if(myInterfaces->Length > 0)
            {
                Console::WriteLine("\n{0} implements the interface {1}.", 
                    myType, myInterfaceList[index]);
                for(int j = 0; j < myInterfaces->Length; j++)
                Console::WriteLine("Interfaces supported: {0}.",
                    myInterfaces[j]);
            }
            else
                Console::WriteLine(
                    "\n{0} does not implement the interface {1}.", 
                    myType, myInterfaceList[index]);

        }
    }
    catch(ArgumentNullException^ e) 
    {
        Console::WriteLine("ArgumentNullException: {0}", e->Message);
    }
    catch(TargetInvocationException^ e) 
    {
        Console::WriteLine("TargetInvocationException: {0}", e->Message);
    }
    catch(Exception^ e) 
    {
        Console::WriteLine("Exception: {0}", e->Message);
    }
}


Version Information

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1
Platforms

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
Microsoft is conducting an online survey to understand your opinion of the MSDN Web site. If you choose to participate, the online survey will be presented to you when you leave the MSDN Web site.

Would you like to participate?