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 built-in as part of the shared framework in .NET Runtime. The package can be installed when you need to use it in other target frameworks.
For more information, see the documentation:
- System.Reflection.Metadata.MetadataReader
- System.Reflection.PortableExecutable.PEReader
- System.Reflection.Metadata.Ecma335.MetadataBuilder
- System.Reflection.PortableExecutable.PEBuilder
- System.Reflection.PortableExecutable.ManagedPEBuilder
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($"Image base: 0x{header.ImageBase.ToString("X")}");
Console.WriteLine($"File alignment: 0x{header.FileAlignment.ToString("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)}");
}
}
}
}
}