CODEWITHSUNDEEP
c#.netreflectionmbunit
George Mauer
George Mauer

Reputation: 122202

How do I get the path of the assembly the code is in?

Is there a way to get the path for the assembly in which the current code resides? I do not want the path of the calling assembly, just the one containing the code.

Basically my unit test needs to read some xml test files which are located relative to the dll. I want the path to always resolve correctly regardless of whether the testing dll is run from TestDriven.NET, the MbUnit GUI or something else.

Edit: People seem to be misunderstanding what I'm asking.

My test library is located in say

C:\projects\myapplication\daotests\bin\Debug\daotests.dll

and I would like to get this path:

C:\projects\myapplication\daotests\bin\Debug\

The three suggestions so far fail me when I run from the MbUnit Gui:

Upvotes: 951

Views: 827551

Answers (29)

John Sibly
John Sibly

Reputation: 23086

Note: Assembly.CodeBase is deprecated in .NET Core/.NET 5+: https://learn.microsoft.com/en-us/dotnet/api/system.reflection.assembly.codebase?view=net-5.0

Original answer:

I've defined the following property as we use this often in unit testing.

public static string AssemblyDirectory
{
    get
    {
        string codeBase = Assembly.GetExecutingAssembly().CodeBase;
        UriBuilder uri = new UriBuilder(codeBase);
        string path = Uri.UnescapeDataString(uri.Path);
        return Path.GetDirectoryName(path);
    }
}

The Assembly.Location property sometimes gives you some funny results when using NUnit (where assemblies run from a temporary folder), so I prefer to use CodeBase which gives you the path in URI format, then UriBuild.UnescapeDataString removes the File:// at the beginning, and GetDirectoryName changes it to the normal windows format.

Upvotes: 1184

Bennik2000
Bennik2000

Reputation: 1156

tl;dr

The concept of an assembly and a DLL file are not the same. Depending on how the assembly was loaded the path information gets lost or is not available at all. Most of the time the provided answers will work, though.

There is one misconception the question and the previous answers have. In most of the cases the provided answers will work just fine but there are cases where it is not possible to get the correct path of the assembly which the current code resides.

The concept of an assembly - which contains executable code - and a dll file - which contains the assembly - are not tightly coupled. An assembly may come from a DLL file but it does not have to.

Using the Assembly.Load(Byte[]) (MSDN) method you can load an assembly directly from a byte array in memory. It does not matter where the byte array comes from. It could be loaded from a file, downloaded from the internet, dynamically generated,...

Here is an example which loads an assembly from a byte array. The path information gets lost after the file was loaded. It is not possible to get the original file path and all previous described methods do not work.

This method is located in the executing assembly which is located at "D:/Software/DynamicAssemblyLoad/DynamicAssemblyLoad/bin/Debug/Runner.exe"

static void Main(string[] args)
{
    var fileContent = File.ReadAllBytes(@"C:\Library.dll");

    var assembly = Assembly.Load(fileContent);

    // Call the method of the library using reflection
    assembly
        ?.GetType("Library.LibraryClass")
        ?.GetMethod("PrintPath", BindingFlags.Public | BindingFlags.Static)
        ?.Invoke(null, null);

    Console.WriteLine("Hello from Application:");
    Console.WriteLine($"GetViaAssemblyCodeBase: {GetViaAssemblyCodeBase(assembly)}");
    Console.WriteLine($"GetViaAssemblyLocation: {assembly.Location}");
    Console.WriteLine($"GetViaAppDomain       : {AppDomain.CurrentDomain.BaseDirectory}");

    Console.ReadLine();
}

This class is located in the Library.dll:

public class LibraryClass
{
    public static void PrintPath()
    {
        var assembly = Assembly.GetAssembly(typeof(LibraryClass));
        Console.WriteLine("Hello from Library:");
        Console.WriteLine($"GetViaAssemblyCodeBase: {GetViaAssemblyCodeBase(assembly)}");
        Console.WriteLine($"GetViaAssemblyLocation: {assembly.Location}");
        Console.WriteLine($"GetViaAppDomain       : {AppDomain.CurrentDomain.BaseDirectory}");
    }
}

For the sake of completeness here is the implementations of GetViaAssemblyCodeBase() which is the same for both assemblies:

private static string GetViaAssemblyCodeBase(Assembly assembly)
{
    var codeBase = assembly.CodeBase;
    var uri = new UriBuilder(codeBase);
    return Uri.UnescapeDataString(uri.Path);
}

The Runner prints the following output:

Hello from Library:
GetViaAssemblyCodeBase: D:/Software/DynamicAssemblyLoad/DynamicAssemblyLoad/bin/Debug/Runner.exe
GetViaAssemblyLocation:
GetViaAppDomain       : D:\Software\DynamicAssemblyLoad\DynamicAssemblyLoad\bin\Debug\
Hello from Application:
GetViaAssemblyCodeBase: D:/Software/DynamicAssemblyLoad/DynamicAssemblyLoad/bin/Debug/Runner.exe
GetViaAssemblyLocation:
GetViaAppDomain       : D:\Software\DynamicAssemblyLoad\DynamicAssemblyLoad\bin\Debug\

As you can see, neither the code base, location or base directory are correct.

Upvotes: 13

cube45
cube45

Reputation: 4049

Starting with .net framework 4.6 / .net core 1.0, there is now a AppContext.BaseDirectory, which should give the same result as AppDomain.CurrentDomain.BaseDirectory, except that AppDomains were not part of the .net core 1.x /.net standard 1.x API.

AppContext.BaseDirectory

EDIT: The documentation now even state:

In .NET 5.0 and later versions, for bundled assemblies, the value returned is the containing directory of the host executable.

Indeed, Assembly.Location doc doc says :

In .NET 5.0 and later versions, for bundled assemblies, the value returned is an empty string.

Upvotes: 22

TPG
TPG

Reputation: 3219

For ASP.Net, it doesn't work. I found a better covered solution at Why AppDomain.CurrentDomain.BaseDirectory not contains "bin" in asp.net app?. It works for both Win Application and ASP.Net Web Application.

public string ApplicationPath
    {
        get
        {
            if (String.IsNullOrEmpty(AppDomain.CurrentDomain.RelativeSearchPath))
            {
                return AppDomain.CurrentDomain.BaseDirectory; //exe folder for WinForms, Consoles, Windows Services
            }
            else
            {
                return AppDomain.CurrentDomain.RelativeSearchPath; //bin folder for Web Apps 
            }
        }
    }

Upvotes: 3

Ilya Chernomordik
Ilya Chernomordik

Reputation: 30345

I believe this would work for any kind of application:

AppDomain.CurrentDomain.RelativeSearchPath ?? AppDomain.CurrentDomain.BaseDirectory

Upvotes: 29

Fedor Shihantsov
Fedor Shihantsov

Reputation: 200

You will get incorrect directory if a path contains the '#' symbol. So I use a modification of the John Sibly answer that is combination UriBuilder.Path and UriBuilder.Fragment:

public static string AssemblyDirectory
{
    get
    {
        string codeBase = Assembly.GetExecutingAssembly().CodeBase;
        UriBuilder uri = new UriBuilder(codeBase);
        //modification of the John Sibly answer    
        string path = Uri.UnescapeDataString(uri.Path.Replace("/", "\\") + 
          uri.Fragment.Replace("/", "\\"));
        return Path.GetDirectoryName(path);
     }
}

Upvotes: 3

gamesguru
gamesguru

Reputation: 92

in a windows form app, you can simply use Application.StartupPath

but for DLLs and console apps the code is much harder to remember...

string slash = Path.DirectorySeparatorChar.ToString();
string root = Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location);

root += slash;
string settingsIni = root + "settings.ini"

Upvotes: 5

Bryan
Bryan

Reputation: 5471

All of the proposed answers work when the developer can change the code to include the required snippet, but if you wanted to do this without changing any code you could use Process Explorer.

It will list all executing dlls on the system, you may need to determine the process id of your running application, but that is usually not too difficult.

I've written a full description of how do this for a dll inside II - http://nodogmablog.bryanhogan.net/2016/09/locating-and-checking-an-executing-dll-on-a-running-web-server/

Upvotes: 4

sumitup
sumitup

Reputation: 61

You can get the bin path by AppDomain.CurrentDomain.RelativeSearchPath

Upvotes: 4

Sneal
Sneal

Reputation: 2586

Same as John's answer, but a slightly less verbose extension method.

public static string GetDirectoryPath(this Assembly assembly)
{
    string filePath = new Uri(assembly.CodeBase).LocalPath;
    return Path.GetDirectoryName(filePath);            
}

Now you can do:

var localDir = Assembly.GetExecutingAssembly().GetDirectoryPath();

or if you prefer:

var localDir = typeof(DaoTests).Assembly.GetDirectoryPath();

Upvotes: 79

George Mauer
George Mauer

Reputation: 122202

In all these years, nobody has actually mentioned this one. A trick I learned from the awesome ApprovalTests project. The trick is that you use the debugging information in the assembly to find the original directory.

This will not work in RELEASE mode, nor with optimizations enabled, nor on a machine different from the one it was compiled on.

But this will get you paths that are relative to the location of the source code file you call it from

public static class PathUtilities
{
    public static string GetAdjacentFile(string relativePath)
    {
        return GetDirectoryForCaller(1) + relativePath;
    }
    public static string GetDirectoryForCaller()
    {
        return GetDirectoryForCaller(1);
    }


    public static string GetDirectoryForCaller(int callerStackDepth)
    {
        var stackFrame = new StackTrace(true).GetFrame(callerStackDepth + 1);
        return GetDirectoryForStackFrame(stackFrame);
    }

    public static string GetDirectoryForStackFrame(StackFrame stackFrame)
    {
        return new FileInfo(stackFrame.GetFileName()).Directory.FullName + Path.DirectorySeparatorChar;
    }
}

Upvotes: 7

Andrey Bushman
Andrey Bushman

Reputation: 12516

I got the same behaviour in the NUnit in the past. By default NUnit copies your assembly into the temp directory. You can change this behaviour in the NUnit settings:

enter image description here

Maybe TestDriven.NET and MbUnit GUI have the same settings.

Upvotes: 1

Tez Wingfield
Tez Wingfield

Reputation: 2251

I find my solution adequate for the retrieval of the location.

var executingAssembly = new FileInfo((Assembly.GetExecutingAssembly().Location)).Directory.FullName;

Upvotes: 1

Keith
Keith

Reputation: 155802

Does this help?

//get the full location of the assembly with DaoTests in it
string fullPath = System.Reflection.Assembly.GetAssembly(typeof(DaoTests)).Location;

//get the folder that's in
string theDirectory = Path.GetDirectoryName( fullPath );

Upvotes: 369

mmmmmm
mmmmmm

Reputation: 1020

This should work:

ExeConfigurationFileMap fileMap = new ExeConfigurationFileMap();
Assembly asm = Assembly.GetCallingAssembly();
String path = Path.GetDirectoryName(new Uri(asm.EscapedCodeBase).LocalPath);

string strLog4NetConfigPath = System.IO.Path.Combine(path, "log4net.config");

I am using this to deploy DLL file libraries along with some configuration file (this is to use log4net from within the DLL file).

Upvotes: 1

Mike Schall
Mike Schall

Reputation: 5899

Here is a VB.NET port of John Sibly's code. Visual Basic is not case sensitive, so a couple of his variable names were colliding with type names.

Public Shared ReadOnly Property AssemblyDirectory() As String
    Get
        Dim codeBase As String = Assembly.GetExecutingAssembly().CodeBase
        Dim uriBuilder As New UriBuilder(codeBase)
        Dim assemblyPath As String = Uri.UnescapeDataString(uriBuilder.Path)
        Return Path.GetDirectoryName(assemblyPath)
    End Get
End Property

Upvotes: 8

Mark Cidade
Mark Cidade

Reputation: 100027

var assembly = System.Reflection.Assembly.GetExecutingAssembly();
var assemblyPath = assembly.GetFiles()[0].Name;
var assemblyDir = System.IO.Path.GetDirectoryName(assemblyPath);

Upvotes: 7

jodonnell
jodonnell

Reputation: 50487

This should work, unless the assembly is shadow copied:

string path = System.Reflection.Assembly.GetExecutingAssembly().Location

Upvotes: 40

Ignacio Soler Garcia
Ignacio Soler Garcia

Reputation: 21855

The only solution that worked for me when using CodeBase and UNC Network shares was:

System.IO.Path.GetDirectoryName(new System.Uri(System.Reflection.Assembly.GetExecutingAssembly().CodeBase).LocalPath);

It also works with normal URIs too.

Upvotes: 52

user2009677
user2009677

Reputation: 442

Web application?

Server.MapPath("~/MyDir/MyFile.ext")

Upvotes: -2

spender
spender

Reputation: 120508

As far as I can tell, most of the other answers have a few problems.

The correct way to do this for a disk-based (as opposed to web-based), non-GACed assembly is to use the currently executing assembly's CodeBase property.

This returns a URL (file://). Instead of messing around with string manipulation or UnescapeDataString, this can be converted with minimal fuss by leveraging the LocalPath property of Uri. 

var codeBaseUrl = Assembly.GetExecutingAssembly().CodeBase;
var filePathToCodeBase = new Uri(codeBaseUrl).LocalPath;
var directoryPath = Path.GetDirectoryName(filePathToCodeBase);

Upvotes: 9

Valamas
Valamas

Reputation: 24759

This is what I came up with. In between web projects, unit tests (nunit and resharper test runner); I found this worked for me.

I have been looking for code to detect what configuration the build is in, Debug/Release/CustomName. Alas, the #if DEBUG. So if someone can improve that!

Feel free to edit and improve.

Getting app folder. Useful for web roots, unittests to get the folder of test files.

public static string AppPath
{
    get
    {
        DirectoryInfo appPath = new DirectoryInfo(AppDomain.CurrentDomain.BaseDirectory);

        while (appPath.FullName.Contains(@"\bin\", StringComparison.CurrentCultureIgnoreCase)
                || appPath.FullName.EndsWith(@"\bin", StringComparison.CurrentCultureIgnoreCase))
        {
            appPath = appPath.Parent;
        }
        return appPath.FullName;
    }
}

Getting bin folder: Useful for executing assemblies using reflection. If files are copied there due to build properties. 

public static string BinPath
{
    get
    {
        string binPath = AppDomain.CurrentDomain.BaseDirectory;

        if (!binPath.Contains(@"\bin\", StringComparison.CurrentCultureIgnoreCase)
            && !binPath.EndsWith(@"\bin", StringComparison.CurrentCultureIgnoreCase))
        {
            binPath = Path.Combine(binPath, "bin");
            //-- Please improve this if there is a better way
            //-- Also note that apps like webapps do not have a debug or release folder. So we would just return bin.
#if DEBUG
            if (Directory.Exists(Path.Combine(binPath, "Debug"))) 
                        binPath = Path.Combine(binPath, "Debug");
#else
            if (Directory.Exists(Path.Combine(binPath, "Release"))) 
                        binPath = Path.Combine(binPath, "Release");
#endif
        }
            return binPath;
    }
}

Upvotes: 1

Jalal El-Shaer
Jalal El-Shaer

Reputation: 14710

It's as simple as this:

var dir = AppDomain.CurrentDomain.BaseDirectory;

Upvotes: 384

rcooley56
rcooley56

Reputation: 11

I use this to get the path to the Bin Directory:

var i = Environment.CurrentDirectory.LastIndexOf(@"\");
var path = Environment.CurrentDirectory.Substring(0,i);

You get this result:

"c:\users\ricooley\documents\visual studio 2010\Projects\Windows_Test_Project\Windows_Test_Project\bin"

Upvotes: -2

dan gibson
dan gibson

Reputation: 3665

I've been using Assembly.CodeBase instead of Location:

Assembly a;
a = Assembly.GetAssembly(typeof(DaoTests));
string s = a.CodeBase.ToUpper(); // file:///c:/path/name.dll
Assert.AreEqual(true, s.StartsWith("FILE://"), "CodeBase is " + s);
s = s.Substring(7, s.LastIndexOf('/') - 7); // 7 = "file://"
while (s.StartsWith("/")) {
    s = s.Substring(1, s.Length - 1);
}
s = s.Replace("/", "\\");

It's been working, but I'm no longer sure it is 100% correct. The page at http://blogs.msdn.com/suzcook/archive/2003/06/26/assembly-codebase-vs-assembly-location.aspx says:

"The CodeBase is a URL to the place where the file was found, while the Location is the path where it was actually loaded. For example, if the assembly was downloaded from the internet, its CodeBase may start with "http://", but its Location may start with "C:\". If the file was shadow-copied, the Location would be the path to the copy of the file in the shadow copy dir. It’s also good to know that the CodeBase is not guaranteed to be set for assemblies in the GAC. Location will always be set for assemblies loaded from disk, however."

You may want to use CodeBase instead of Location.

Upvotes: 6

Jesse C. Slicer
Jesse C. Slicer

Reputation: 20157

string path = Path.GetDirectoryName(typeof(DaoTests).Module.FullyQualifiedName);

Upvotes: 2

huseyint
huseyint

Reputation: 15081

What about this:

System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location);

Upvotes: 15

Curt Hagenlocher
Curt Hagenlocher

Reputation: 20916

I suspect that the real issue here is that your test runner is copying your assembly to a different location. There's no way at runtime to tell where the assembly was copied from, but you can probably flip a switch to tell the test runner to run the assembly from where it is and not to copy it to a shadow directory.

Such a switch is likely to be different for each test runner, of course.

Have you considered embedding your XML data as resources inside your test assembly?

Upvotes: 12

David Basarab
David Basarab

Reputation: 73351

The current directory where you exist.

Environment.CurrentDirectory;  // This is the current directory of your application

If you copy the .xml file out with build you should find it.

or

System.Reflection.Assembly assembly = System.Reflection.Assembly.GetAssembly(typeof(SomeObject));

// The location of the Assembly
assembly.Location;

Upvotes: 3

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