Assembly.Load Method

Definition

Namespace:

System.Reflection

Assembly:

System.Runtime.dll

Loads an assembly.

Overloads

Load(Byte[])	Loads the assembly with a common object file format (COFF)-based image containing an emitted assembly.
Load(String)	Loads an assembly with the specified name.
Load(AssemblyName)	Loads an assembly given its AssemblyName.
Load(Byte[], Byte[])	Loads the assembly with a common object file format (COFF)-based image containing an emitted assembly, optionally including symbols for the assembly.

Load(Byte[])

Source:

Assembly.cs

Loads the assembly with a common object file format (COFF)-based image containing an emitted assembly.

public:
 static System::Reflection::Assembly ^ Load(cli::array <System::Byte> ^ rawAssembly);

public static System.Reflection.Assembly Load (byte[] rawAssembly);

static member Load : byte[] -> System.Reflection.Assembly

Public Shared Function Load (rawAssembly As Byte()) As Assembly

Parameters

rawAssembly

Byte[]

A byte array that is a COFF-based image containing an emitted assembly.

Returns

Assembly

The loaded assembly.

Exceptions

ArgumentNullException

rawAssembly is null.

BadImageFormatException

rawAssembly is not a valid assembly for the currently loaded runtime.

Remarks

This method overload always creates a new Assembly object in its own isolated load context.

.NET Framework only: The trust level of an assembly that is loaded by using this method is the same as the trust level of the calling assembly. To load an assembly from a byte array with the trust level of the application domain, use the Load(Byte[], Byte[], SecurityContextSource) method overload. For more information about the use of evidence with overloads of the Load method that take byte arrays, see the Load(Byte[], Byte[], Evidence) method overload.

Load(String)

Source:

Assembly.CoreCLR.cs

Loads an assembly with the specified name.

public:
 static System::Reflection::Assembly ^ Load(System::String ^ assemblyString);

public static System.Reflection.Assembly Load (string assemblyString);

static member Load : string -> System.Reflection.Assembly

Public Shared Function Load (assemblyString As String) As Assembly

Parameters

assemblyString

String

The long or short form of the assembly name.

Returns

Assembly

The loaded assembly.

Exceptions

ArgumentNullException

assemblyString is null.

ArgumentException

assemblyString is a zero-length string.

FileNotFoundException

assemblyString is not found.

FileLoadException

A file that was found could not be loaded.

BadImageFormatException

assemblyString is not a valid assembly for the currently loaded runtime.

Examples

The following example loads an assembly given its fully qualified name, and lists all the types contained in the specified assembly. For information about how to obtain the fully qualified assembly name, see Assembly Names.

using namespace System;
using namespace System::Collections;
using namespace System::Reflection;
int main()
{
    // You must supply a valid fully qualified assembly name.            
    Assembly^ SampleAssembly = Assembly::Load
        ( "SampleAssembly, Version=1.0.2004.0, Culture=neutral, PublicKeyToken=8744b20f8da049e3" );
    array<Type^>^ Types = SampleAssembly->GetTypes();
    
    // Display all the types contained in the specified assembly.
    IEnumerator^ myEnum = Types->GetEnumerator();
    Type^ oType;
    while ( myEnum->MoveNext() )
    {
        oType = safe_cast<Type^>(myEnum->Current);
        Console::WriteLine( oType->Name );
    }
}

using System;
using System.Reflection;

class Class1
{
    public static void Main()
    {
        // You must supply a valid fully qualified assembly name.
        Assembly SampleAssembly = Assembly.Load
            ("SampleAssembly, Version=1.0.2004.0, Culture=neutral, PublicKeyToken=8744b20f8da049e3");
        // Display all the types contained in the specified assembly.
        foreach (Type oType in SampleAssembly.GetTypes()) {
            Console.WriteLine(oType.Name);
        }
    }
}

Imports System.Reflection

Class Class1
    Public Shared Sub Main()
        ' You must supply a valid fully qualified assembly name.            
        Dim SampleAssembly As [Assembly] = _
            [Assembly].Load("SampleAssembly, Version=1.0.2004.0, Culture=neutral, PublicKeyToken=8744b20f8da049e3")
        Dim oType As Type
        ' Display all the types contained in the specified assembly.
        For Each oType In SampleAssembly.GetTypes()
            Console.WriteLine(oType.Name)
        Next oType
    End Sub	'LoadSample
End Class

Remarks

In .NET Core/5+, the target assembly is loaded into the current AssemblyLoadContext. For more information on assembly loading, see Managed assembly loading algorithm.

To load the correct assembly, it's recommended to call the Load method by passing the long form of the assembly name. The long form of an assembly name consists of its simple name (such as "System" for the System.dll assembly) along with its version, culture, public key token, and optionally its processor architecture. It corresponds to the assembly's FullName property. The following example illustrates the use of a long name to load the System.dll assembly for the .NET Framework 4:

using System;
using System.Reflection;

public class Example
{
   public static void Main()
   {
      string longName = "system, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089";
      Assembly assem = Assembly.Load(longName);
      if (assem == null)
         Console.WriteLine("Unable to load assembly...");
      else
         Console.WriteLine(assem.FullName);
   }
}
// The example displays the following output:
//        system, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089

Imports System.Reflection

Module Example
   Public Sub Main()
      Dim longName As String = "system, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
      Dim assem As Assembly = Assembly.Load(longName)
      If assem Is Nothing Then
         Console.WriteLine("Unable to load assembly...")
      Else
         Console.WriteLine(assem.FullName)
      End If
   End Sub
End Module
' The example displays the following output:
'       system, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089

FileLoadException is thrown if assemblyString 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.

In the .NET Framework version 2.0, processor architecture is added to assembly identity, and can be specified as part of assembly name strings. For example, "ProcessorArchitecture=msil". However, the recommended way to specify an assembly name is to create an AssemblyName object and pass it to an appropriate overload of the Load method. See AssemblyName.ProcessorArchitecture.

See also

• AssemblyName
• LoadFrom(String)
• How the Runtime Locates Assemblies

Load(AssemblyName)

Source:

Assembly.CoreCLR.cs

Loads an assembly given its AssemblyName.

public:
 static System::Reflection::Assembly ^ Load(System::Reflection::AssemblyName ^ assemblyRef);

public static System.Reflection.Assembly Load (System.Reflection.AssemblyName assemblyRef);

static member Load : System.Reflection.AssemblyName -> System.Reflection.Assembly

Public Shared Function Load (assemblyRef As AssemblyName) As Assembly

Parameters

assemblyRef

AssemblyName

The object that describes the assembly to be loaded.

Returns

Assembly

The loaded assembly.

Exceptions

ArgumentNullException

assemblyRef is null.

FileNotFoundException

assemblyRef is not found.

FileLoadException

A file that was found could not be loaded.

-or-

.NET Framework only: assemblyRef specifies a location that is disabled based on <loadFromRemoteSources>.

Note: In .NET for Windows Store apps or the Portable Class Library, catch the base class exception, IOException, instead.

BadImageFormatException

assemblyRef is not a valid assembly for the currently loaded runtime.

Examples

The following example instantiates an AssemblyName object and uses it to load the sysglobal.dll assembly. The example then displays the full name of the assembly's public types.

using System;
using System.Reflection;

public class Example
{
   public static void Main()
   {
      String fullName = "sysglobl, Version=4.0.0.0, Culture=neutral, " +
                        "PublicKeyToken=b03f5f7f11d50a3a, processor architecture=MSIL";
      var an = new AssemblyName(fullName);
      var assem = Assembly.Load(an);
      Console.WriteLine("Public types in assembly {0}:", assem.FullName);
      foreach (var t in assem.GetTypes())
         if (t.IsPublic)
            Console.WriteLine("   {0}", t.FullName);
   }
}
// The example displays the following output:
//   Public types in assembly sysglobl, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a:
//      System.Globalization.CultureAndRegionInfoBuilder
//      System.Globalization.CultureAndRegionModifiers

Imports System.Reflection

Module Example
   Public Sub Main()
      Dim fullName As String = "sysglobl, Version=4.0.0.0, Culture=neutral, " +
                               "PublicKeyToken=b03f5f7f11d50a3a, processor architecture=MSIL"
      Dim an As New AssemblyName(fullName)
      Dim assem As Assembly = Assembly.Load(an)
      Console.WriteLine("Public types in assembly {0}:", assem.FullName)
      For Each t As Type in assem.GetTypes()
         If t.IsPublic Then Console.WriteLine("   {0}", t.FullName)
      Next
   End Sub
End Module
' The example displays the following output:
'   Public types in assembly sysglobl, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a:
'      System.Globalization.CultureAndRegionInfoBuilder
'      System.Globalization.CultureAndRegionModifiers

Remarks

In .NET Core/.NET 5+, the target assembly will be loaded into the current AssemblyLoadContext. For more information on assembly loading, see Managed assembly loading algorithm.

Note

.NET Framework only: For information about loading assemblies from remote locations, see <loadFromRemoteSources>.

Note

.NET Framework only: 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.

Note

.NET Framework only: 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.

See also

• AssemblyName
• How the Runtime Locates Assemblies

Load(Byte[], Byte[])

Source:

Assembly.cs

Loads the assembly with a common object file format (COFF)-based image containing an emitted assembly, optionally including symbols for the assembly.

public:
 static System::Reflection::Assembly ^ Load(cli::array <System::Byte> ^ rawAssembly, cli::array <System::Byte> ^ rawSymbolStore);

public static System.Reflection.Assembly Load (byte[] rawAssembly, byte[]? rawSymbolStore);

static member Load : byte[] * byte[] -> System.Reflection.Assembly

Public Shared Function Load (rawAssembly As Byte(), rawSymbolStore As Byte()) As Assembly

Parameters

rawAssembly

Byte[]

A byte array that is a COFF-based image containing an emitted assembly.

rawSymbolStore

Byte[]

A byte array that contains the raw bytes representing the symbols for the assembly.

Returns

Assembly

The loaded assembly.

Exceptions

ArgumentNullException

rawAssembly is null.

BadImageFormatException

rawAssembly is not a valid assembly for the currently loaded runtime.

Remarks

In .NET Core/5+, the target assembly is loaded into the current AssemblyLoadContext. For more information on assembly loading, see Managed assembly loading algorithm.

This method overload always creates a new Assembly object in its own isolated load context.

.NET Framework only: The trust level of an assembly that is loaded by using this method is the same as the trust level of the calling assembly. To load an assembly from a byte array with the trust level of the application domain, use the Load(Byte[], Byte[], SecurityContextSource) method overload. For more information about the use of evidence with overloads of the Load method that take byte arrays, see the Load(Byte[], Byte[], Evidence) method overload.