How can I decompile a batch of .NET DLLs into a Visual Studio project

Question

I just need to search for bits of text in my C# code.

I already have .NET Reflector and the File Disassembler Add-In, but these just seem to decompile one DLL.

Solution

Actually, none of these answers are right.

Yeah, all the tools can decompile *.dll files into *.csproj file but none of them supports CLI or batch processing. You can save yourself the time with installations.

The best possible solution so far is use dotPeek, put all *.dll files into one folder and use Explore Folder option.

dotPeek will analyse the given folder and shows a tree of DLLs located inside the folder. You can generate csproj manually for every single dll which is loaded.

---

If you came across this post because you are looking answer how locate specific instruction in your or 3rd party dlls, specially a use of reflection, you can use this PowerShell script to decompile dlls into IL and look for the instruction (System.Reflection.Assembly::Load(string) for reflection).

Note

It is using Intermediate Language DisASseMbler (ILDASM) from .NET Framework SDK kit. Adjust the path accordingly to your version of SDK.

function Get-LibDump
{
    Param(
# Specifies a path to one or more locations. Wildcards are permitted.
    [Parameter(Mandatory=$true,
            Position=0,
            ParameterSetName="Basic",
            ValueFromPipeline=$true,
            ValueFromPipelineByPropertyName=$true,
            HelpMessage="Path to one or more locations.")]
    [ValidateNotNullOrEmpty()]
    [SupportsWildcards()]
    [ValidateScript({$_ | Test-Path})]
    [System.IO.FileInfo]
    $Path
    )
    process
    {
        $dumpFileFilePath = $Path.BaseName + '.il'
        $outFile = "C:\LibDump\$dumpFileFilePath"
        Start-Process -FilePath 'c:\Program Files (x86)\Microsoft SDKs\Windows\v10.0A\bin\NETFX 4.7.2 Tools\ildasm.exe' -ArgumentList "/UNICODE /OUT=`"$outFile`" `"$($Path.FullName)`"" -Wait
        "Dump from:`n$(Resolve-Path -Path $Path.FullName -Relative)" | Out-File -FilePath $outFile -Encoding:unicode -Append
    }
}

# Use
Get-ChildItem -Path $PathToLibFolder -Filter '*.dll' -File -Recurse | Get-LibDump

Comments

[Nyerguds]

"Actually, none of these answers are right" - Admitted, you expanded a lot on the details, but one of the original answers from 2012 does mention dotPeek. Anyway, these kind of questions are generally considered off-topic nowadays since anything asking for the best tool to use is bound to just get answered with people's personal opinions.

[KUTlime]

I consider the fact that"opinion based" questions are actively forced away from SO like one of the biggest downfall of SO. With more and more years in IT, I consider opinion of more experience guys as one of the best resources. Yeah, there is a lot of trolls out there but there is kind and smart people too. 🤷🏿‍♀️

[t9mike]

ILSpy now supports multi-DLL decompile to C# code with their stand-alone GUI. It even creates an sln file. github.com/icsharpcode/ILSpy