System Reflection Metadata

About

This package provides a low-level.NET (ECMA-335) metadata reader and writer. It's geared for performance and is the ideal choice for building higher-level libraries that intend to provide their own object model, such as compilers. The metadata format is defined by the ECMA-335 - Common Language Infrastructure (CLI) specification and its amendments.

The System.Reflection.Metadata library is included in the.NET Runtime shared framework. The package can be installed when you need to use it in other target frameworks.

How to Use

The following example shows how to read assembly information using PEReader and MetadataReader.

using System;

using System.IO;

using System.Reflection.Metadata;

using System.Reflection.PortableExecutable;

class Program

{

static void Main()

{

// Open the Portable Executable (PE) file

using var fs = new FileStream("Example.dll", FileMode.Open, FileAccess.Read, FileShare.ReadWrite);

using var peReader = new PEReader(fs);

// Display PE header information

PEHeader header = peReader.PEHeaders.PEHeader;

Console.WriteLine($"Image base: 0x{header.ImageBase:X}");

Console.WriteLine($"File alignment: 0x{header.FileAlignment:X}");

Console.WriteLine($"Subsystem: {header.Subsystem}");

// Display.NET metadata information

if (!peReader.HasMetadata)

{

Console.WriteLine("Image does not contain.NET metadata");

return;

}

MetadataReader mr = peReader.GetMetadataReader();

AssemblyDefinition ad = mr.GetAssemblyDefinition();

Console.WriteLine($"Assembly name: {ad.GetAssemblyName().ToString()}");

Console.WriteLine();

Console.WriteLine("Assembly attributes:");

foreach (CustomAttributeHandle attrHandle in ad.GetCustomAttributes())

{

CustomAttribute attr = mr.GetCustomAttribute(attrHandle);

// Display the attribute type full name

if (attr.Constructor.Kind == HandleKind.MethodDefinition)

{

MethodDefinition mdef = mr.GetMethodDefinition((MethodDefinitionHandle)attr.Constructor);

TypeDefinition tdef = mr.GetTypeDefinition(mdef.GetDeclaringType());

Console.WriteLine($"{mr.GetString(tdef.Namespace)}.{mr.GetString(tdef.Name)}");

}

else if (attr.Constructor.Kind == HandleKind.MemberReference)

{

MemberReference mref = mr.GetMemberReference((MemberReferenceHandle)attr.Constructor);

if (mref.Parent.Kind == HandleKind.TypeReference)

{

TypeReference tref = mr.GetTypeReference((TypeReferenceHandle)mref.Parent);

Console.WriteLine($"{mr.GetString(tref.Namespace)}.{mr.GetString(tref.Name)}");

}

else if (mref.Parent.Kind == HandleKind.TypeDefinition)

{

TypeDefinition tdef = mr.GetTypeDefinition((TypeDefinitionHandle)mref.Parent);

Console.WriteLine($"{mr.GetString(tdef.Namespace)}.{mr.GetString(tdef.Name)}");

}

}

}

}

}

Main Types

The main types provided by this library are:

• System.Reflection.Metadata.MetadataReader
• System.Reflection.PortableExecutable.PEReader
• System.Reflection.Metadata.Ecma335.MetadataBuilder
• System.Reflection.PortableExecutable.PEBuilder
• System.Reflection.PortableExecutable.ManagedPEBuilder

Additional Documentation

• System.Reflection.Metadata.MetadataReader
• System.Reflection.PortableExecutable.PEReader
• System.Reflection.Metadata.Ecma335.MetadataBuilder
• System.Reflection.PortableExecutable.PEBuilder
• System.Reflection.PortableExecutable.ManagedPEBuilder

Feedback & Contributing

System.Reflection.Metadata is released as open source under the MIT license. Bug reports and contributions are welcome at the GitHub repository.