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ConstructorInfo Class

Discovers the attributes of a class constructor and provides access to constructor metadata.

Namespace: System.Reflection
Assembly: mscorlib (in mscorlib.dll)

'Declaration
<SerializableAttribute> _
<ComVisibleAttribute(True)> _
<ClassInterfaceAttribute(ClassInterfaceType.None)> _
Public MustInherit Class ConstructorInfo
	Inherits MethodBase
	Implements _ConstructorInfo
'Usage
Dim instance As ConstructorInfo

/** @attribute SerializableAttribute() */ 
/** @attribute ComVisibleAttribute(true) */ 
/** @attribute ClassInterfaceAttribute(ClassInterfaceType.None) */ 
public abstract class ConstructorInfo extends MethodBase implements _ConstructorInfo
SerializableAttribute 
ComVisibleAttribute(true) 
ClassInterfaceAttribute(ClassInterfaceType.None) 
public abstract class ConstructorInfo extends MethodBase implements _ConstructorInfo
Not applicable.

ConstructorInfo is used to discover the attributes of a constructor as well as to invoke a constructor. Objects are created by calling Invoke on a ConstructorInfo returned by either the GetConstructors or GetConstructor method of a Type object.

NoteNote:

ConstructorInfo inherits from MethodBase several members, such as IsGenericMethod, that can be used to examine generic methods. In the .NET Framework version 2.0 constructors cannot be generic, so these members return false or a null reference (Nothing in Visual Basic).

Notes to Inheritors: When you inherit from ConstructorInfo, you must override the following member overload: Invoke(BindingFlags,Binder,Object[],CultureInfo).

The following example uses ConstructorInfo with GetConstructor and BindingFlags to find the constructors that match the specified search criteria.

Public Class MyClass1
    Public Sub New(ByVal i As Integer)
    End Sub
    Public Shared Sub Main()
        Try
            Dim myType As Type = GetType(MyClass1)
            Dim types(0) As Type
            types(0) = GetType(Integer)
            ' Get the public instance constructor that takes an integer parameter.
            Dim constructorInfoObj As ConstructorInfo = _
                        myType.GetConstructor(BindingFlags.Instance Or _
                        BindingFlags.Public, Nothing, _
                        CallingConventions.HasThis, types, Nothing)
            If Not (constructorInfoObj Is Nothing) Then
                Console.WriteLine("The constructor of MyClass1 that " + _
                                  "is a public instance method and takes an " + _
                                  "integer as a parameter is: ")
                Console.WriteLine(constructorInfoObj.ToString())
            Else
                Console.WriteLine("The constructor MyClass1 that " + _
                                  "is a public instance method and takes an " + _
                                  "integer as a parameter is not available.")
            End If
        Catch e As ArgumentNullException
            Console.WriteLine("ArgumentNullException: " + e.Message)
        Catch e As ArgumentException
            Console.WriteLine("ArgumentException: " + e.Message)
        Catch e As SecurityException
            Console.WriteLine("SecurityException: " + e.Message)
        Catch e As Exception
            Console.WriteLine("Exception: " + e.Message)
        End Try
    End Sub
End Class

import System.*;
import System.Reflection.*;
import System.Security.*;

public class MyClass1
{
    public MyClass1(int i)
    {
    } //MyClass1

    public static void main(String[] args)
    {
        try {
            Type myType = MyClass1.class.ToType();
            Type types[] = new Type[1];
            types.set_Item(0, int.class.ToType());
            // Get the public instance constructor that takes an
            // integer parameter.
            ConstructorInfo constructorInfoObj =
                myType.GetConstructor(BindingFlags.Instance|BindingFlags.Public,
                null, CallingConventions.HasThis, types, null);
            if (constructorInfoObj != null) {
                Console.WriteLine("The constructor of MyClass1 that is a public "
                    + "instance method and takes an integer as a parameter is: ");
                Console.WriteLine(constructorInfoObj.ToString());
            }
            else {
                Console.WriteLine("The constructor of MyClass1 that is a "
                    + "public instance method and takes an integer "
                    + "as a parameter is not available.");
            }
        }
        catch (ArgumentNullException e) {
            Console.WriteLine("ArgumentNullException: " + e.get_Message());
        }
        catch (ArgumentException e) {
            Console.WriteLine("ArgumentException: " + e.get_Message());
        }
        catch (SecurityException e) {
            Console.WriteLine("SecurityException: " + e.get_Message());
        }
        catch (System.Exception e) {
            Console.WriteLine("Exception: " + e.get_Message());
        }
    } //main
} //MyClass1

This type is thread safe.

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

XNA Framework

Supported in: 1.0

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