How to use ICSharpCode.Decompiler to decompile a whole assembly to a text file?

Question

I need to get either the whole IL Code or Decompiled Source Code to a text file. Is that possible with the ILSpy Decompile Engine ICSharpCode.Decompiler?

Answer 1

With ILSpy, you can select an assembly node in the tree view, and then use File > Save Code to save the result to disk. ILSpy will use the currently selected language to do so, so it can both disassemble and decompile. When decompiling to C#, the save dialog will have options for saving a C# project (.csproj) with separate source code files per class; or a single C# file (.cs) for the whole assembly.

---

To decompile programmatically, use the ICSharpCode.Decompiler library (available on NuGet). E.g. decompile whole assembly to a string:

var decompiler = new CSharpDecompiler(assemblyFileName, new DecompilerSettings());
string code = decompiler.DecompileWholeModuleAsString();

See the ICSharpCode.Decompiler.Console project for slightly more advanced usage of the decompiler API. The part with resolver.AddSearchDirectory(path); in that console project may be relevant, because the decompiler needs to find the referenced assemblies.

---

The ICSharpCode.Decompiler library also has a disassembler API (which is a bit more low-level):

string code;
using (var peFileStream = new FileStream(sourceFileName, FileMode.Open, FileAccess.Read))
using (var peFile = new PEFile(sourceFileName, peFileStream))
using (var writer = new StringWriter()) {
    var output = new PlainTextOutput(writer);
    ReflectionDisassembler rd = new ReflectionDisassembler(output, CancellationToken.None);
    rd.DetectControlStructure = false;
    rd.WriteAssemblyReferences(peFile.Metadata);
    if (metadata.IsAssembly)
        rd.WriteAssemblyHeader(peFile);
    output.WriteLine();
    rd.WriteModuleHeader(peFile);
    output.WriteLine();
    rd.WriteModuleContents(peFile);

    code = writer.ToString();
}