Activator.CreateInstanceFrom Method (String, String)

 

Creates an instance of the type whose name is specified, using the named assembly file and default constructor.

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

public static ObjectHandle CreateInstanceFrom(
	string assemblyFile,
	string typeName
)

Parameters

assemblyFile
Type: System.String

The name of a file that contains an assembly where the type named typeName is sought.

typeName
Type: System.String

The name of the preferred type.

Return Value

Type: System.Runtime.Remoting.ObjectHandle

A handle that must be unwrapped to access the newly created instance.

Exception Condition
ArgumentNullException

typeName is null.

MissingMethodException

No matching public constructor was found.

TypeLoadException

typename was not found in assemblyFile.

FileNotFoundException

assemblyFile was not found.

MethodAccessException

The caller does not have permission to call this constructor.

MemberAccessException

Cannot create an instance of an abstract class, or this member was invoked with a late-binding mechanism.

TargetInvocationException

The constructor, which was invoked through reflection, threw an exception.

SecurityException

The caller does have the required FileIOPermission.

BadImageFormatException

assemblyFile is not a valid assembly.

-or-

The common language runtime (CLR) version 2.0 or later is currently loaded, and assemblyName was compiled for a version of the CLR that is later than the currently loaded version. Note that the .NET Framework versions 2.0, 3.0, and 3.5 all use CLR version 2.0.

Use the ObjectHandle.Unwrap method to unwrap the return value.

For information about other exceptions that can be thrown by invoked methods, see the Exceptions section of the Assembly.LoadFrom and CreateInstance methods.

The following code example demonstrates how to call the CreateInstanceFrom method. This code example is part of a larger example provided for the Activator class.

// Create an instance of the SomeType class that is defined in this 
// assembly.
System.Runtime.Remoting.ObjectHandle oh = 
    Activator.CreateInstanceFrom(Assembly.GetEntryAssembly().CodeBase, 
                                 typeof(SomeType).FullName);

// Call an instance method defined by the SomeType type using this object.
SomeType st = (SomeType) oh.Unwrap();

st.DoSomething(5);

SecurityPermission

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

FileIOPermission

for the ability to search directory paths and read their contents. Associated enumerations: FileIOPermissionAccess.PathDiscovery and FileIOPermissionAccess.Read

ReflectionPermission

for accessing nonpublic types when the grant set of the nonpublic types is restricted to the caller's grant set or to a subset thereof. Associated enumeration: ReflectionPermissionFlag.RestrictedMemberAccess

ReflectionPermission

for accessing nonpublic types regardless of their grant set. Associated enumeration: ReflectionPermissionFlag.MemberAccess

.NET Framework
Available since 1.1
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