We Keep Coding

Location of original assembly(not the current executing)

Suppose I have a solution which contains 4 projects, A, A_UnitTests, B, and B_UnitTests.
Project A has a data file, which is added as a link to A_UnitTests and set to copy to the output directory. When unit tests are run or when the code is executed in production, the path to that file is correctly identified using the following code snippet:
public static string GetFullPath(string relativePath)
{
string retVal = string.Empty;
if (System.Web.HttpContext.Current == null)
{
string locationBeforeShadowCopy = typeof(A.SomeClassInA).Assembly.CodeBase;
UriBuilder uri = new UriBuilder(locationBeforeShadowCopy);
string locationWithoutUriPrefixes = Uri.UnescapeDataString(uri.Path);
string dir = Path.GetDirectoryName(locationWithoutUriPrefixes);
retVal = Path.Combine(dir, relativePath);
}
else
{
// stuff that doesn't matter
}
return retVal;
}
However, I have a new testcase in B_UnitTests which attempts to use this code path to find the file location. However, even though I call typeof(A.SomeClassInA).Assembly.CodeBase, it is being called from B_UnitTests, using its referenced DLLs. This means the path return is the B_UnitTests output directory + a relative path. So it doesn't find the data file.
Without resorting to hard coded settings and build scripts, what could I use to specify the correct path?
Update (clarification)
The real issue is with typeForClassInA.Assembly.CodeBase returning the path of the executing assembly rather than A itself. It seems very wrong to provide a type that comes from some assembly but instead of returning the original assembly location, it returns the path to the executing assembly which happens to have a reference to it.

If there is a reference to 'typeForClassInA', then its assembly will be being copied into the output directory of B_UnitTests. So when you ask for CodeBase of that type's assembly from a test in B_UnitTests, it is (correctly) pointing at the version of assembly A in the B_UnitTests output folder, because that's where it's being loaded from.
I admit that I avoid using Shadow Copy to avoid exactly these kinds of problems of locating resources which are alongside the assembly, since ShadowCopy doesn't understand that they are needed, and they don't get shadow copied.
Another thing which can help is to build all the projects into the same output folder by changing all the project output folders to be "..\bin". For example, this would mean that A_UnitTests would not need the link to the resource file (once shadow copy is off).
I have a method similar to the one you've shown which goes "up" from the assembly's location (which for me is the shared bin folder) to the solution's location; and my relative paths are 'rooted' at that folder.
If that all sounds too complex, you could just use the same approach that A_UnitTests did, of including a link to it from B_UnitTests.

How to recursively load all referenced assemblies? [duplicate]

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:
Environment.CurrentDirectory
gives c:\Program Files\MbUnit
System.Reflection.Assembly.GetAssembly(typeof(DaoTests)).Location
gives C:\Documents and
Settings\george\Local
Settings\Temp\ ....\DaoTests.dll
System.Reflection.Assembly.GetExecutingAssembly().Location
gives the same as the previous.

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.

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 );

It's as simple as this:
var dir = AppDomain.CurrentDomain.BaseDirectory;

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();

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.

This should work, unless the assembly is shadow copied:
string path = System.Reflection.Assembly.GetExecutingAssembly().Location

I believe this would work for any kind of application:
AppDomain.CurrentDomain.RelativeSearchPath ?? AppDomain.CurrentDomain.BaseDirectory

What about this:
System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location);

AppDomain.CurrentDomain.BaseDirectory
works with MbUnit GUI.

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.

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?

How about this ...
string ThisdllDirectory = System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location);
Then just hack off what you do not need

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.

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);

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

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

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;
}
}

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.

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;

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

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/

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"

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);
}
}

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
}
}
}

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

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;
}
}

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).

I find my solution adequate for the retrieval of the location.
var executingAssembly = new FileInfo((Assembly.GetExecutingAssembly().Location)).Directory.FullName;

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

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"

How to get Current Project Directory path using C#

okay, here is the question. I have two projects one is C# Console and other is Class library.
I am accessing/calling Class library method from the console app.
There is a folder called Files within the class library project.
I need to get the path of the Class library's files folder but whenever I use
System.IO.Directory.GetCurrentDirectory();
and
Environment.CurrentDirectory;
it is giving me path of the Console project which I am using to call the method.
Above methods are giving me path like
C:\\ConsolePro\\bin\\Debug
but I need the path of Class library project
C:\\ClassLibPro\\bin\\Debug
Please advise

Once the code is compiled and running, 'Project Path' has no meaning. All you can determine are the file locations of the compiled assemblies. And you can only do what you are asking if your Console project references the built 'class library' DLL directly, rather than via a Project Reference.
Then, you can make use of Reflection to get Assembly paths like;
string path = Assembly.GetAssembly(typeof (SomeClassInOtherProject)).Location;

You should be able to use Directory.GetParent(Directory.GetCurrentDirectory()) a few times to get higher level directories and then add the path of the lib directory to the end of that.

I believe the problem is:
Since the Console project has the DLL file reference it is using DLL to call any methods.
At this time it is returning the class library projct's DLL location which is located in console project's bin directory and it doesn't know about the physical location of class library project.
so essentially it is returning the same project path. I will have to move both projects in same directory in order to solve this issue.

If you loading the class library from another assembly.
string Path = System.Reflection.Assembly.GetAssembly(typeof({LibraryClassName})).Location;
string PathToClassLibPro = Path.GetDirectoryName( Path);
Replace {LibraryClassName} with the class name of your library.

I hope I understand u corretly:
Path.GetDirectoryName(typeof(Foo.MyFooClass).Assembly.Location);

I would recommend one of two options.
If the files are small include them in the class library and stream them to a temp location when needed
Other option is to copy the files during the build to the output directory and use them that way. In cases of multiple shared projects it is best to have a common bin folder that you copy assemblies to and run from that location.

Despite i cant find a good solution i use this trick :
as long as you want to come back to your ideal path u should add Directory.GetParent() instead of ...
Directory.GetParent(...(Directory.GetParent(Directory.GetCurrentDirectory()).ToString()...).ToString()

I use the following approach to get the current project path at runtime:
public static class ProjectInfo {
public static string appDirectory = AppDomain.CurrentDomain.BaseDirectory;
public static string projectPath = appDirectory.Substring(0, appDirectory.IndexOf("\\bin"));
}

I had this exact issue as well where I couldn't access the file in my namespace's bin/debug folder. My solution was to manipulate the string using Split() then construct a new string which is the absolute path to the json file I have in my namespace.
private static string GetFilePath()
{
const char Escape = '\\'; //can't have '\' by itself, it'll throw the "Newline in constant" error
string directory = Environment.CurrentDirectory;
string[] pathOccurences = directory.Split(Escape);
string pathToReturn = pathOccurences[0] + Escape; //prevents index out of bounds in upcoming loop
for(int i = 1; i < pathOccurences.Length; i++)
{
if (pathOccurences[i] != pathOccurences[i - 1]) //the project file name and the namespace file name are the same
pathToReturn += pathOccurences[i] + Escape;
else
pathToReturn += typeof(thisClass).Namespace + Escape; //In the one occurrence of the duplicate substring, I replace it with my class Namespace name
}
return pathToReturn + "yourFile.json";
}
I personally don't like this solution, but it was the only answer I could think of.

How can I build Application.UserAppDataPath inside class libraries (that don't have an Application object)?

Winforms and Console Applications can use Application.UserAppDataPath.
What if I want to build the same path from a dll? How can I do that?
I know that Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData) would be the start...

Here is a method that will do what you want. This works in a WPF application without adding System.Windows.Forms.dll
public string GetUserAppDataPath()
{
string path = string.Empty;
System.Reflection.Assembly assm;
try
{
assm = System.Reflection.Assembly.GetEntryAssembly();
Type at = typeof(System.Reflection.AssemblyCompanyAttribute);
object[] r = assm.GetCustomAttributes(at, false);
System.Reflection.AssemblyCompanyAttribute ct = ((System.Reflection.AssemblyCompanyAttribute)(r[0]));
path = Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData);
path += #"\" + ct.Company;
path += #"\" + assm.GetName().Version.ToString();
}
catch
{
}
return path;
}

You can use Application.UserAppDataPath from a DLL - simply add a reference to the System.Windows.Forms assembly from your DLL project.
However be aware that if your DLL is used in a Windows Service or Server application such as ASP.NET, it may run under an service account that does not have a profile - in this case UserAppDataPath won't exist. This is probably the main reason the Application class is in the System.Windows.Forms namespace.

Well, if you don't have an application object that you can use, you would start out with what you mentioned to get the "ApplicationData" folder path, then append the default folder structure on to that path.
CompanyName/ProductName
is the default additional items

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:
Environment.CurrentDirectory
gives c:\Program Files\MbUnit
System.Reflection.Assembly.GetAssembly(typeof(DaoTests)).Location
gives C:\Documents and
Settings\george\Local
Settings\Temp\ ....\DaoTests.dll
System.Reflection.Assembly.GetExecutingAssembly().Location
gives the same as the previous.

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.

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 );

It's as simple as this:
var dir = AppDomain.CurrentDomain.BaseDirectory;

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();

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.

This should work, unless the assembly is shadow copied:
string path = System.Reflection.Assembly.GetExecutingAssembly().Location

I believe this would work for any kind of application:
AppDomain.CurrentDomain.RelativeSearchPath ?? AppDomain.CurrentDomain.BaseDirectory

What about this:
System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location);

AppDomain.CurrentDomain.BaseDirectory
works with MbUnit GUI.

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.

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?

How about this ...
string ThisdllDirectory = System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location);
Then just hack off what you do not need

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.

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);

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

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

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;
}
}

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.

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;

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

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/

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"

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);
}
}

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
}
}
}

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

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;
}
}

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).

I find my solution adequate for the retrieval of the location.
var executingAssembly = new FileInfo((Assembly.GetExecutingAssembly().Location)).Directory.FullName;

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

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"