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Type.GetConstructors Method (BindingFlags)

When overridden in a derived class, searches for the constructors defined for the current Type, using the specified BindingFlags.

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

[ComVisibleAttribute(true)] 
public abstract ConstructorInfo[] GetConstructors (
	BindingFlags bindingAttr
)
/** @attribute ComVisibleAttribute(true) */ 
public abstract ConstructorInfo[] GetConstructors (
	BindingFlags bindingAttr
)
ComVisibleAttribute(true) 
public abstract function GetConstructors (
	bindingAttr : BindingFlags
) : ConstructorInfo[]
Not applicable.

Parameters

bindingAttr

A bitmask comprised of one or more BindingFlags that specify how the search is conducted.

-or-

Zero, to return a null reference (Nothing in Visual Basic).

Return Value

An array of ConstructorInfo objects representing all constructors defined for the current Type that match the specified binding constraints, including the type initializer if it is defined. Returns an empty array of type ConstructorInfo if no constructors are defined for the current Type, if none of the defined constructors match the binding constraints, or if the current Type represents a type parameter in the definition of a generic type or generic method.

The GetConstructors method does not return constructors in a particular order, such as declaration order. Your code must not depend on the order in which constructors are returned, because that order varies.

bindingAttr can be used to specify whether to return only public constructors or both public and non-public constructors.

If an exact match does not exist, the binder will attempt to coerce the parameter types specified in the types array in order to select a match. If the binder is unable to select a match, then a null reference (Nothing in Visual Basic) is returned.

The following BindingFlags filter flags can be used to define which constructors to include in the search:

  • You must specify either BindingFlags.Instance or BindingFlags.Static in order to get a return.

  • Specify BindingFlags.Public to include public constructors in the search.

  • Specify BindingFlags.NonPublic to include non-public constructors (that is, private and protected constructors) in the search.

See System.Reflection.BindingFlags for more information.

If the requested constructor is non-public and the caller does not have ReflectionPermission to reflect non-public objects outside the current assembly, this method returns a null reference (Nothing in Visual Basic).

To get the class initializer (.cctor) using this method overload, you must specify BindingFlags.Static | BindingFlags.NonPublic (BindingFlags.StaticOrBindingFlags.NonPublic in Visual Basic). You can also get the class initializer using the TypeInitializer property.

If the current Type represents a constructed generic type, this method returns the ConstructorInfo objects with the type parameters replaced by the appropriate type arguments. For example, if class C<T> has a constructor C(T t1) (Sub New(ByVal t1 As T) in Visual Basic), calling GetConstructors on C<int> returns a ConstructorInfo that represents C(int t1) in C# (Sub New(ByVal t1 As Integer) in Visual Basic).

If the current Type represents a generic type parameter, the GetConstructors method returns an empty array.

This example shows the output of the GetConstructors overload from a class that has two instance constructors and one static constructor.

using System;
using System.Reflection;

public class t {
    public t() {}
    static t() {}
    public t(int i) {}

    public static void Main() {
        ConstructorInfo[] p = typeof(t).GetConstructors();
        Console.WriteLine(p.Length);

        for (int i=0;i<p.Length;i++) {
            Console.WriteLine(p[i].IsStatic);
        }
    }
}

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

public class T
{
    public T()
    {
    } //T

    static 
    {
    } //T

    public T(int i)
    {
    } //T

    public static void main(String[] args)
    {
        ConstructorInfo p[] = T.class.ToType().GetConstructors();
        Console.WriteLine(p.length);
        for (int i=0;i < p.length;i++) {
            Console.WriteLine(p[i].get_IsStatic());
        } 
    } //main
} //T

import System;
import System.Reflection;

public class t {
    public function t() {}
    static t {}
    public function t(i : int) {}

    public static function Main(): void  {
        var p : ConstructorInfo[] = t.GetConstructors();
        Console.WriteLine(p.Length);

        for (var i : int =0;i<p.Length;i++) {
            Console.WriteLine(p[i].IsStatic);
        }
    }
}
t.Main();

The output of this code is:

2

False

False

Because the GetConstructors overload uses only Public and Instance, the static constructor is neither counted by the for expression nor evaluated by IsStatic.

To find static constructors, use the GetConstructors overload, and pass it the combination (logical OR) of BindingFlags.Public, BindingFlags.Static, BindingFlags.NonPublic, BindingFlags.Instance, as shown in the following code example:

using System;
using System.Reflection;
 
public class t {
    public t() {}
    static t() {}
    public t(int i) {}

    public static void Main() {
        ConstructorInfo[] p = typeof(t).GetConstructors(
           BindingFlags.Public | BindingFlags.Static |
           BindingFlags.NonPublic | BindingFlags.Instance);
        Console.WriteLine(p.Length);

        for (int i=0;i<p.Length;i++) {
            Console.WriteLine(p[i].IsStatic);
        }
    }
}

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

public class T
{
    public T() 
    {
    } //T

    static
    {
    } //T

    public T(int i)
    {
    } //T

    public static void main(String[] args)
    {
        ConstructorInfo p[] = T.class.ToType().GetConstructors(
            (BindingFlags.Public | BindingFlags.Static | BindingFlags.NonPublic
            | BindingFlags.Instance)); 
        Console.WriteLine(p.length);
        for (int i=0;i< p.length;i++) {
            Console.WriteLine(p[i].get_IsStatic());
        } 
    } //main
} //T

import System;
import System.Reflection;
 
public class t {
    public function t() {}
    static t {}
    public function t(i : int) {}

    public static function Main() : void  {
        var p : ConstructorInfo[] = t.GetConstructors(
           BindingFlags.Public | BindingFlags.Static |
           BindingFlags.NonPublic | BindingFlags.Instance);
        Console.WriteLine(p.Length);

        for (var i:int=0;i<p.Length;i++) {
            Console.WriteLine(p[i].IsStatic);
        }
    }
}
t.Main();

Now the output is:

3

False

True

False

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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