Type.FindInterfaces Method
Returns an array of Type objects representing a filtered list of interfaces implemented or inherited by the current Type.
[Visual Basic] Public Overridable Function FindInterfaces( _ ByVal filter As TypeFilter, _ ByVal filterCriteria As Object _ ) As Type() [C#] public virtual Type[] FindInterfaces( TypeFilter filter, object filterCriteria ); [C++] public: virtual Type* FindInterfaces( TypeFilter* filter, Object* filterCriteria ) []; [JScript] public function FindInterfaces( filter : TypeFilter, filterCriteria : Object ) : Type[];
Parameters
- filter
- The TypeFilter delegate that compares the interfaces against filterCriteria.
- filterCriteria
- The search criteria that determines whether an interface should be included in the returned array.
Return Value
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.
Exceptions
| Exception Type | Condition |
|---|---|
| ArgumentNullException | filter is a 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.
Example
[Visual Basic, C#, C++] The following example finds the specified interface implemented or inherited by the specified type, and then displays the interface names.
[Visual Basic] 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 [C#] 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; } } [C++] #using <mscorlib.dll> #using <system.xml.dll> using namespace System; using namespace System::Xml; using namespace System::Reflection; public __gc 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 = new XmlDocument(); myXMLDoc->LoadXml(S"<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(0, MyFindInterfacesSample::MyInterfaceFilter); String* myInterfaceList[] = {S"System.Collections.IEnumerable", S"System.Collections.ICollection"}; for (int index=0; index < myInterfaceList->Length; index++) { Type* myInterfaces[] = myType->FindInterfaces(myFilter, myInterfaceList[index]); if (myInterfaces->Length > 0) { Console::WriteLine(S"\n{0} implements the interface {1}.", myType, myInterfaceList[index]); for (int j =0;j < myInterfaces->Length;j++) Console::WriteLine(S"Interfaces supported: {0}.", myInterfaces[j]); } else Console::WriteLine(S"\n{0} does not implement the interface {1}.", myType, myInterfaceList[index]); } } catch (ArgumentNullException* e) { Console::WriteLine(S"ArgumentNullException: {0}", e->Message); } catch (TargetInvocationException* e) { Console::WriteLine(S"TargetInvocationException: {0}", e->Message); } catch (Exception* e) { Console::WriteLine(S"Exception: {0}", e->Message); } }
[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button
in the upper-left corner of the page.
Requirements
Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family
See Also
Type Class | Type Members | System Namespace | Module | TypeFilter | GetInterface | GetInterfaces