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Type.GetConstructor Method (Type[])

April 12, 2014

Searches for a public instance constructor whose parameters match the types in the specified array.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)
public ConstructorInfo GetConstructor(
	Type[] types
)

Parameters

types
Type: System.Type []
An array of Type objects representing the number, order, and type of the parameters for the desired constructor.
-or-
An empty array of Type objects, to get a constructor that takes no parameters. Such an empty array is provided by the static field Type.EmptyTypes.

Return Value

Type: System.Reflection.ConstructorInfo
A ConstructorInfo object representing the public instance constructor whose parameters match the types in the parameter type array, if found; otherwise, null.
ExceptionCondition
ArgumentNullException

types is null.

-or-

One of the elements in types is null.

ArgumentException

types is multidimensional.

This method overload looks for public instance constructors and cannot be used to obtain a class initializer (.cctor). To get a class initializer, use an overload that takes BindingFlags, and specify BindingFlags.Static | BindingFlags.NonPublic (BindingFlags.StaticOrBindingFlags.NonPublic in Visual Basic).

If the requested constructor is non-public, this method returns null.

NoteNote:

You cannot omit parameters when looking up constructors and methods. You can only omit parameters when invoking.

If the current Type represents a constructed generic type, this method returns the ConstructorInfo with the type parameters replaced by the appropriate type arguments. If the current Type represents a type parameter in the definition of a generic type or generic method, this method always returns null.

The following example obtains the type of MyClass, gets the ConstructorInfo object, and displays the constructor signature.



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

public class Example
{
    public Example() { }
    public Example(int i) { }

    public static void Demo(System.Windows.Controls.TextBlock outputBlock)
    {
        Type myType = typeof(Example);
        Type[] parameters = { typeof(int) };

        // Get the constructor that takes an integer as a parameter.
        ConstructorInfo ctor = myType.GetConstructor(parameters);

        if (ctor == null)
        {
            outputBlock.Text += 
                "There is no public constructor of MyClass that takes an integer as a parameter.\n";
        }
        else
        {
            outputBlock.Text += 
                "The public constructor of MyClass that takes an integer as a parameter is:\n"; 
            outputBlock.Text += ctor.ToString() + "\n";
        }
    }
}

/* This example produces the following output:

The public constructor of MyClass that takes an integer as a parameter is:
Void .ctor(Int32)
 */


Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

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