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Assembly.Load Method (AssemblyName, Evidence)

Updated: October 2008

Loads an assembly given its AssemblyName. The assembly is loaded into the domain of the caller using the supplied evidence.

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

public static Assembly Load(
	AssemblyName assemblyRef,
	Evidence assemblySecurity
)

Parameters

assemblyRef
Type: System.Reflection.AssemblyName

The AssemblyName object that describes the assembly to be loaded.

assemblySecurity
Type: System.Security.Policy.Evidence

Evidence for loading the assembly.

Return Value

Type: System.Reflection.Assembly
The loaded assembly.

ExceptionCondition
ArgumentNullException

assemblyRef is null.

FileNotFoundException

assemblyRef is not found.

BadImageFormatException

assemblyRef is not a valid assembly.

-or-

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

FileLoadException

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

FileLoadException is thrown if assemblyRef specifies the full assembly name, and the first assembly that matches the simple name has a different version, culture, or public key token. The loader does not continue probing for other assemblies that match the simple name.

NoteNote:

Do not use an AssemblyName with only the CodeBase property set. The CodeBase property does not supply any elements of the assembly identity (such as name or version), so loading does not occur according to load-by-identity rules, as you would expect from the Load method. Instead, the assembly is loaded using load-from rules. For information about the disadvantages of using the load-from context, see the Assembly.LoadFrom method overload or Best Practices for Assembly Loading.

Whether certain permissions are granted or not granted to an assembly is based on evidence. The rules for assembly and security evidence merging are as follows:

  • When you use a Load method with no Evidence parameter, the assembly is loaded with the evidence that the loader supplies.

  • When you use a Load method with an Evidence parameter, pieces of evidence are merged. Pieces of evidence supplied as an argument to the Load method supersede pieces of evidence supplied by the loader.

  • When you use a Load method overload with a Byte[] parameter to load a common object file format (COFF) image, evidence is inherited from the calling assembly. This applies to the .NET Framework version 1.1 Service Pack 1 (SP1) and subsequent releases.

    NoteNote:

    In the .NET Framework version 1.0 and in version 1.1 without SP1, when you use a Load method overload with a Byte[] parameter to load a COFF image, evidence is combined. Zone, Url and Site are inherited from the calling assembly, and Hash and StrongName are taken from the COFF assembly.

  • When you use a Load method with a Byte[] parameter and Evidence to load a COFF image, only the supplied evidence is used. Evidence of the calling assembly and evidence of the COFF image is ignored.

Reflecting on C++ executable files might throw a BadImageFormatException. This is most likely caused by C++ compiler stripping the relocation addresses or the .reloc section from your executable file. To preserve the .reloc address for your C++ executable file, specify /fixed:no when you are linking.

NoteNote:

If both the AssemblyName.Name property and the AssemblyName.CodeBase property are set, the first attempt to load the assembly uses the display name (including version, culture, and so on, as returned by the Assembly.FullName property). If the file is not found, CodeBase is used to search for the assembly. If the assembly is found using CodeBase, the display name is matched against the assembly. If the match fails, a FileLoadException is thrown.

If you call this method more than once on the same assembly but with a different evidence specified, the common language runtime does not throw a FileLoadException because the equality and integrity of the different evidence specifications cannot be determined. The evidence that first succeeds is the evidence that is used.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

Date

History

Reason

October 2008

Added warning about using only CodeBase to load assemblies.

Content bug fix.

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