CreateInstance Method (String, String, Object[])

AppDomain.CreateInstance Method (String, String, Object[])


Creates a new instance of the specified type defined in the specified assembly. A parameter specifies an array of activation attributes.

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

public ObjectHandle CreateInstance(
	string assemblyName,
	string typeName,
	object[] activationAttributes


Type: System.String

The display name of the assembly. See Assembly.FullName.

Type: System.String

The fully qualified name of the requested type, including the namespace but not the assembly, as returned by the Type.FullName property.

Type: System.Object[]

An array of one or more attributes that can participate in activation. Typically, an array that contains a single UrlAttribute object that specifies the URL that is required to activate a remote object.

This parameter is related to client-activated objects.Client activation is a legacy technology that is retained for backward compatibility but is not recommended for new development. Distributed applications should instead use Windows Communication Foundation.

Return Value

Type: System.Runtime.Remoting.ObjectHandle

An object that is a wrapper for the new instance specified by typeName. The return value needs to be unwrapped to access the real object.

Exception Condition

The operation is attempted on an unloaded application domain.


assemblyName or typeName is null.


assemblyName is not a valid assembly.


Version 2.0 or later of the common language runtime is currently loaded and assemblyName was compiled with a later version.


An assembly or module was loaded twice with two different evidences.


assemblyName was not found.


The caller does not have permission to call this constructor.


No matching public constructor was found.


The caller cannot provide activation attributes for an object that does not inherit from MarshalByRefObject.


typename was not found in assemblyName.


This instance is null.

This method calls the default constructor for typeName.

See AssemblyName for the format of assemblyName.

An attempt to call CreateInstance on a target application domain that is not the current application domain will result in a successful load of the assembly in the target application domain. Since an Assembly is not MarshalByRefObject, when this method attempts to return the Assembly for the loaded assembly to the current application domain, the common language runtime will try to load the assembly into the current application domain and the load might fail. The assembly that is loaded into the current application domain might be different from the assembly that was loaded first if the path settings for the two application domains are different.


for the ability to access the location of the assembly. Associated enumeration: FileIOPermissionAccess.PathDiscovery


for the ability to read the file containing the assembly manifest. Associated enumeration: FileIOPermissionAccess.Read


for the ability to access the location of the assembly if the assembly is not local.


for the ability to call unmanaged code when creating an instance of a delegate. Associated enumeration: SecurityPermissionFlag.UnmanagedCode


for the ability to invoke operations on all type members. Associated enumeration: ReflectionPermissionFlag.MemberAccess

.NET Framework
Available since 1.1
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