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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
)

Parameters

bindingAttr
Type: System.Reflection.BindingFlags
A bitmask comprised of one or more BindingFlags that specify how the search is conducted.
-or-
Zero, to return null.

Return Value

Type: System.Reflection.ConstructorInfo[]
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.

Implements

_Type.GetConstructors(BindingFlags)

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 null 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, internal, and protected constructors) in the search. Constructors of base classes are not returned.

See System.Reflection.BindingFlags for more information.

To get the class initializer (.cctor) using this method overload, you must specify BindingFlags.Static | BindingFlags.NonPublic (BindingFlags.Static Or BindingFlags.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);
        }
    }
}


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);
        }
    }
}


Now the output is:

3

False

True

False

.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

Portable Class Library

Supported in: Portable Class Library

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.

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