ConstructorInfo Class

July 28, 2014

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

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

public abstract class ConstructorInfo : MethodBase

The ConstructorInfo type exposes the following members.

  NameDescription
Public propertyAttributesGets the attributes associated with this method. (Inherited from MethodBase.)
Public propertyCallingConventionGets a value that indicates the calling conventions for this method. (Inherited from MethodBase.)
Public propertyContainsGenericParametersGets a value that indicates whether the generic method contains unassigned generic type parameters. (Inherited from MethodBase.)
Public propertyCustomAttributesGets a collection that contains this member's custom attributes. (Inherited from MemberInfo.)
Public propertyDeclaringTypeGets the class that declares this member. (Inherited from MemberInfo.)
Public propertyIsAbstractGets a value that indicates whether the method is abstract (MustInherit in Visual Basic). (Inherited from MethodBase.)
Public propertyIsAssemblyGets a value that indicates whether the potential visibility of this method or constructor is described by MethodAttributes.Assembly; that is, the method or constructor is visible at most to other types in the same assembly, and is not visible to derived types outside the assembly. (Inherited from MethodBase.)
Public propertyIsConstructorGets a value that indicates whether the method is a constructor. (Inherited from MethodBase.)
Public propertyIsFamilyGets a value that indicates whether the visibility of this method or constructor is described by MethodAttributes.Family; that is, the method or constructor is visible only within its class and derived classes. (Inherited from MethodBase.)
Public propertyIsFamilyAndAssemblyGets a value that indicates whether the visibility of this method or constructor is described by MethodAttributes.FamANDAssem; that is, the method or constructor can be called by derived classes, but only if they are in the same assembly. (Inherited from MethodBase.)
Public propertyIsFamilyOrAssemblyGets a value that indicates whether the potential visibility of this method or constructor is described by MethodAttributes.FamORAssem; that is, the method or constructor can be called by derived classes wherever they are, and by classes in the same assembly. (Inherited from MethodBase.)
Public propertyIsFinalGets a value that indicates whether this method is final (NotOverridable in Visual Basic). (Inherited from MethodBase.)
Public propertyIsGenericMethodGets a value that indicates whether the method is generic. (Inherited from MethodBase.)
Public propertyIsGenericMethodDefinitionGets a value that indicates whether the method is a generic method definition. (Inherited from MethodBase.)
Public propertyIsHideBySigGets a value that indicates whether only a member of the same kind with exactly the same signature is hidden in the derived class. (Inherited from MethodBase.)
Public propertyIsPrivateGets a value that indicates whether this member is private. (Inherited from MethodBase.)
Public propertyIsPublicGets a value that indicates whether this is a public method. (Inherited from MethodBase.)
Public propertyIsSpecialNameGets a value that indicates whether this method has a special name. (Inherited from MethodBase.)
Public propertyIsStaticGets a value that indicates whether the method is static (Shared in Visual Basic). (Inherited from MethodBase.)
Public propertyIsVirtualGets a value that indicates whether the method is virtual (Overridable in Visual Basic). (Inherited from MethodBase.)
Public propertyMemberTypeGets a MemberTypes value indicating that this member is a constructor. (Overrides MemberInfo.MemberType.)
Public propertyMetadataTokenGets a value that identifies a metadata element. (Inherited from MemberInfo.)
Public propertyMethodHandleGets a handle to the internal metadata representation of a method. (Inherited from MethodBase.)
Public propertyMethodImplementationFlagsGets the MethodImplAttributes flags that specify the attributes of a method implementation. (Inherited from MethodBase.)
Public propertyModuleGets the module in which the type that declares the member represented by the current MemberInfo is defined. (Inherited from MemberInfo.)
Public propertyNameGets the name of the current member. (Inherited from MemberInfo.)
Public propertyReflectedTypeGets the class object that was used to obtain this instance of MemberInfo. (Inherited from MemberInfo.)
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  NameDescription
Public methodEqualsReturns a value that indicates whether this instance is equal to a specified object. (Overrides MethodBase.Equals(Object).)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetCustomAttributes(Boolean)When overridden in a derived class, returns an array of all custom attributes applied to this member. (Inherited from MemberInfo.)
Public methodGetCustomAttributes(Type, Boolean)When overridden in a derived class, returns an array of custom attributes applied to this member and identified by Type. (Inherited from MemberInfo.)
Public methodGetGenericArgumentsReturns an array of Type objects that represent the type arguments of a generic method or the type parameters of a generic method definition. (Inherited from MethodBase.)
Public methodGetHashCodeReturns the hash code for this instance. (Overrides MethodBase.GetHashCode().)
Public methodGetMethodImplementationFlagsWhen overridden in a derived class, returns the MethodImplAttributes flags. (Inherited from MethodBase.)
Public methodGetParametersWhen overridden in a derived class, gets the parameters of this method or constructor. (Inherited from MethodBase.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodInvoke(Object[])Invokes the current constructor with the specified arguments.
Public methodInvoke(Object, Object[])Invokes the method or constructor represented by the current instance, using the specified parameters. (Inherited from MethodBase.)
Public methodInvoke(BindingFlags, Binder, Object[], CultureInfo)When implemented in a derived class, invokes the current constructor with the specified arguments, using the specified binder and culture to validate the argument types.
Public methodInvoke(Object, BindingFlags, Binder, Object[], CultureInfo)When overridden in a derived class, invokes the reflected method or constructor with the given parameters. (Inherited from MethodBase.)
Public methodIsDefinedWhen overridden in a derived class, indicates whether one or more attributes of the specified type or of its derived types is applied to this member. (Inherited from MemberInfo.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)
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  NameDescription
Public Extension MethodGetCustomAttribute(Type)Overloaded. Retrieves a custom attribute of a specified type that is applied to a specified member. (Defined by CustomAttributeExtensions.)
Public Extension MethodGetCustomAttribute(Type, Boolean)Overloaded. Retrieves a custom attribute of a specified type that is applied to a specified member, and optionally inspects the ancestors of that member. (Defined by CustomAttributeExtensions.)
Public Extension MethodGetCustomAttribute<T>()Overloaded. Retrieves a custom attribute of a specified type that is applied to a specified member. (Defined by CustomAttributeExtensions.)
Public Extension MethodGetCustomAttribute<T>(Boolean)Overloaded. Retrieves a custom attribute of a specified type that is applied to a specified member, and optionally inspects the ancestors of that member. (Defined by CustomAttributeExtensions.)
Public Extension MethodGetCustomAttributes()Overloaded. Retrieves a collection of custom attributes that are applied to a specified member. (Defined by CustomAttributeExtensions.)
Public Extension MethodGetCustomAttributes(Type)Overloaded. Retrieves a collection of custom attributes of a specified type that are applied to a specified member. (Defined by CustomAttributeExtensions.)
Public Extension MethodGetCustomAttributes<T>()Overloaded. Retrieves a collection of custom attributes of a specified type that are applied to a specified member. (Defined by CustomAttributeExtensions.)
Public Extension MethodGetCustomAttributes<T>(Boolean)Overloaded. Retrieves a collection of custom attributes of a specified type that are applied to a specified member, and optionally inspects the ancestors of that member. (Defined by CustomAttributeExtensions.)
Public Extension MethodIsDefinedIndicates whether custom attributes of a specified type are applied to a specified member. (Defined by CustomAttributeExtensions.)
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  NameDescription
Public fieldStatic memberConstructorNameRepresents the name of the class constructor method as it is stored in metadata. This name is always ".ctor". This field is read-only.
Public fieldStatic memberTypeConstructorNameRepresents the name of the type constructor method as it is stored in metadata. This name is always ".cctor". This property is read-only.
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In Windows Phone, you cannot derive from this type.

ConstructorInfo is used to discover the attributes of a constructor and 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 several members from MethodBase, such as IsGenericMethod, that can be used to examine generic methods. Constructors cannot be generic, so these members return false or null.

Version Notes

Windows Phone

 If you call a static constructor using reflection, the application throws ArgumentException instead of MethodAccessException.

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


using System;
using System.Reflection;
using System.Security;

public class Example
{
    public Example(int i){}
    public static void Demo(System.Windows.Controls.TextBlock outputBlock)
    {
        try
        {
            Type  myType = typeof(Example);
            Type[] types = new Type[1];
            types[0] = typeof(int);
            // Get the public instance constructor that takes an integer parameter.
            ConstructorInfo constructorInfoObj = myType.GetConstructor(
                BindingFlags.Instance | BindingFlags.Public, null, types, null);
            if(constructorInfoObj != null)
            {
                outputBlock.Text += "The constructor of Example that is a public " +
                    "instance method and takes an integer as a parameter is: " + Environment.NewLine;
                outputBlock.Text += constructorInfoObj.ToString() + Environment.NewLine;
            }
            else
            {
                outputBlock.Text += "The constructor of Example that is a public instance " +
                    "method and takes an integer as a parameter is not available." + Environment.NewLine;
            }
        }
        catch(ArgumentNullException e)
        {
            outputBlock.Text += "ArgumentNullException: " + e.Message + Environment.NewLine;
        }
        catch(ArgumentException e)
        {
            outputBlock.Text += "ArgumentException: " + e.Message + Environment.NewLine;
        }
        catch(SecurityException e)
        {
            outputBlock.Text += "SecurityException: " + e.Message + Environment.NewLine;
        }
        catch(Exception e)
        {
            outputBlock.Text += "Exception: " + e.Message + Environment.NewLine;
        }
    }
}


Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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