Develop Reference

How to reference another DLL in Roslyn dynamically-compiled code

I'm writing a project that dynamically compiles and executes c# code. The problem is that sometimes I want the code to call another DLL (for the sake of this sample I called it "ANOTHER.DLL"). It works fine in .Net 4.5, but fails in .Net Core and I can't figure out why. Any help is appreciated!
Code compiles successfully, but gives an error when the method is executed. Error is:
FileNotFoundException: Could not load file or assembly 'ANOTHER,
Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'. The system
cannot find the file specified.
The ANOTHER.dll is located in the same /bin/debug folder, and is definitely accessible (code compiles!)
I noticed I can fix the issue by adding reference to ANOTHER.DLL to the project, but it defeats the purpose of dynamic compilation.
I tried this in .Net Core 2.0 - 3.1
ANOTHER.DLL is .Net Standard 2.0 (but same result with .Net Standard 2.1, or .Net Framework).
Also tried various versions of Microsoft.CodeAnalysis package, all giving me same error.
var eval = new Evaluator();
string code = #"
using System;
namespace RoslynCompileSample
{
public class Test
{
public string Hello{
get {
//return ""Hello"";
var c = new ANOTHER.Class1();
return c.HelloWorld();
}
}
}
}";
SyntaxTree syntaxTree = CSharpSyntaxTree.ParseText(code);
var assemblyPath = Path.GetDirectoryName(typeof(object).Assembly.Location);
List < MetadataReference > references = new List < MetadataReference > ();
references.Add(MetadataReference.CreateFromFile(typeof(object).GetTypeInfo().Assembly.Location));
string ReferenceList = "";
ReferenceList += "netstandard.dll\n";
ReferenceList += "System.Runtime.dll\n";
ReferenceList += "ANOTHER.dll\n";
string[] assemblies = ReferenceList.Split('\n');
foreach(string a in assemblies) {
if (File.Exists(Path.Combine(assemblyPath, a.Trim()))) {
references.Add(MetadataReference.CreateFromFile(Path.Combine(assemblyPath, a.Trim())));
}
else if (File.Exists(a.Trim())) {
string currDirectory = Directory.GetCurrentDirectory();
references.Add(MetadataReference.CreateFromFile(Path.Combine(currDirectory, a.Trim())));
}
else {
string exepath = Path.GetDirectoryName(Assembly.GetEntryAssembly().Location);
if (File.Exists(Path.Combine(exepath, a.Trim()))) {
references.Add(MetadataReference.CreateFromFile(Path.Combine(exepath, a.Trim())));
}
}
}
CSharpCompilation compilation = CSharpCompilation.Create("assembly", syntaxTrees: new[] {
syntaxTree
},
references: references, options: new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary, optimizationLevel: OptimizationLevel.Release));
Assembly assembly;
using(var ms = new MemoryStream()) {
EmitResult result = compilation.Emit(ms);
ms.Seek(0, SeekOrigin.Begin);
assembly = Assembly.Load(ms.ToArray());
}
var type = assembly.GetType("RoslynCompileSample.Test");
var prop = type.GetProperties();
var all = prop.Where(x =>x.Name == "Hello");
var info = all.FirstOrDefault(x =>x.DeclaringType == type) ? ?all.First();
var method = info.GetGetMethod();
object obj;
obj = assembly.CreateInstance("RoslynCompileSample.Test");
object r = method.Invoke(obj, new object[] {}); // this is where the error occurs

Solution is based on my gist
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.Emit;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Runtime.Loader;
namespace ConsoleApp2
{
class Program
{
static void Main(string[] args)
{
string code = #"
using System;
namespace RoslynCompileSample
{
public class Test
{
public string Hello{
get {
//return ""Hello"";
var c = new ANOTHER.Class1();
return c.HelloWorld();
}
}
}
}";
var tree = SyntaxFactory.ParseSyntaxTree(code);
string fileName = "mylib.dll";
var assemblyPath = Path.GetDirectoryName(typeof(object).Assembly.Location);
List<MetadataReference> references = new List<MetadataReference>();
references.Add(MetadataReference.CreateFromFile(typeof(object).GetTypeInfo().Assembly.Location));
references.Add(MetadataReference.CreateFromFile(Path.Combine(assemblyPath, "netstandard.dll")));
references.Add(MetadataReference.CreateFromFile(Path.Combine(assemblyPath, "System.Runtime.dll")));
references.Add(MetadataReference.CreateFromFile(Path.Combine(assemblyPath, "System.Private.CoreLib.dll")));
var anotherDLLReference = MetadataReference.CreateFromFile(#"C:\Users\jjjjjjjjjjjj\source\repos\ConsoleApp2\ANOTHER\bin\Debug\netcoreapp3.1\ANOTHER.dll");
references.Add(anotherDLLReference);
var compilation = CSharpCompilation.Create(fileName)
.WithOptions(
new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary))
.AddReferences(references)
.AddSyntaxTrees(tree);
string path = Path.Combine(Directory.GetCurrentDirectory(), fileName);
EmitResult compilationResult = compilation.Emit(path);
if (compilationResult.Success)
{
// Load the assembly
Assembly assembly = AssemblyLoadContext.Default.LoadFromAssemblyPath(path);
var type = assembly.GetType("RoslynCompileSample.Test");
var prop = type.GetProperties();
var all = prop.Where(x => x.Name == "Hello");
var info = all.FirstOrDefault(x => x.DeclaringType == type) ?? all.First();
var method = info.GetGetMethod();
object obj;
obj = assembly.CreateInstance("RoslynCompileSample.Test");
object r = method.Invoke(obj, new object[] { });
}
}
}
}
To be fair, I have 0 idea how it works, since I am not familiar with working with assemblies on this level, but somehow I managed to get rid of exception.
Firstly, I checked AssemblyLoadContext.Default in the debugger. I noticed that reference to "ANOTHER.dll" is missing (although we previously added it)
Then I added AssemblyLoadContext.Default.LoadFromAssemblyPath(#"path to my ANOTHER.dll");. And when I checked it again - ANOTHER.dll was there.
Finally, we can see our hello world message
So the code I added is basically one line
// Load the assembly
Assembly assembly = AssemblyLoadContext.Default.LoadFromAssemblyPath(path);
var a = AssemblyLoadContext.Default.LoadFromAssemblyPath(#"C:\Users\jjjjjjjjjjjj\source\repos\ConsoleApp2\ANOTHER\bin\Debug\netcoreapp3.1\ANOTHER.dll");
var type = assembly.GetType("RoslynCompileSample.Test");
This works with both ANOTHER.dll targeting Standard 2.0 and .NET Core 3.1
Would be nice if someone smart actually told how it works.

Roslyn doesn't work correctly with .net Framework Console app and Docker

We have an issue where simple c# code executed via CSharpCodeProvider doesn't work the same on running local command line and docker.
Code example is below, and it will not return any Types of the assembly when run on Roslyn, but works fine locally.
I have literally no idea how to debug this from here - any help welcome!
using System;
using Microsoft.CodeDom.Providers.DotNetCompilerPlatform;
using System.IO;
using System.Reflection;
using System.Text;
using System.CodeDom.Compiler;
namespace TestContainerIssue
{
class Program
{
static void Main(string[] args)
{
using (var codeProvider = new CSharpCodeProvider())
{
var compilerParameters = new CompilerParameters
{
GenerateExecutable = false,
GenerateInMemory = true
};
compilerParameters.CompilerOptions = String.Format("/lib:\"{0}\"", Path.GetDirectoryName(Uri.UnescapeDataString((new UriBuilder(Assembly.GetExecutingAssembly().CodeBase)).Path)));
Console.WriteLine(compilerParameters.CompilerOptions);
compilerParameters.ReferencedAssemblies.Add("System.dll");
compilerParameters.ReferencedAssemblies.Add("System.Core.dll");
CompilerResults compilerResults = codeProvider.CompileAssemblyFromSource(compilerParameters, ExecutionWrapperCode);
if (compilerResults.Errors.HasErrors)
{
StringBuilder errors = new StringBuilder();
foreach (CompilerError error in compilerResults.Errors)
errors.AppendLine(error.ErrorText);
throw new Exception(errors.ToString());
}
Console.WriteLine(compilerResults.PathToAssembly);
Assembly assembly = compilerResults.CompiledAssembly;
Console.WriteLine(assembly.FullName);
Console.WriteLine("Types:");
foreach (Type t in assembly.GetTypes())
{
Console.WriteLine(t);
}
Type type = assembly.GetType("Validation.Execution");
Console.WriteLine("Type:");
Console.WriteLine(type); //Empty when run in Docker (both mcr.microsoft.com/windows:1909 and mcr.microsoft.com/windows/servercore:ltsc2019
var methodInfo = type.GetMethod("Execute");
Console.WriteLine(methodInfo);
}
}
private const string ExecutionWrapperCode = #"
using System;
namespace Validation
{
public static class Execution
{
public static string Execute()
{
return ""test"";
}
}
}";
}
}
I tried below docker file (I tried two windows image: mcr.microsoft.com/windows:1909 and mcr.microsoft.com/windows/servercore:ltsc2019
FROM mcr.microsoft.com/windows/servercore:ltsc2019
ADD /bin/Debug /
ENTRYPOINT TestContainerIssue.exe
EDIT: I built the two dlls, and compared them in dotPeek - as you can see the one in Docker is missing the namespace. They are exactly the same bytes length though.

It turns out this line of code:
compilerParameters.CompilerOptions = String.Format("/lib:\"{0}\"", Path.GetDirectoryName(Uri.UnescapeDataString((new UriBuilder(Assembly.GetExecutingAssembly().CodeBase)).Path)));
was causing the problem. I don't know why it causes it and doesn't throw an error in compiler, but perhaps will help someone else.
Was

(C#) Compiling class at runtime and calling methods from original code

I'm trying to compile code at runtime in C#, then from the compiled code call a function or initialize a class which is defined in the original code.
The code I currently have:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Microsoft.CSharp;
using System.CodeDom.Compiler;
using System.Reflection;
namespace CTFGame
{
class Program
{
static void Main(string[] args)
{
string code = #"
using System;
namespace CTFGame
{
public class MyPlayer
{
public static void Main ()
{
Console.WriteLine(""Hello world"");
}
/*public void DoTurn ()
{
Program.SayHello();
}*/
}
}
";
CSharpCodeProvider provider = new CSharpCodeProvider();
CompilerParameters parameters = new CompilerParameters();
parameters.GenerateInMemory = true;
CompilerResults results = provider.CompileAssemblyFromSource(parameters, code);
if (results.Errors.HasErrors)
{
string errors = "";
foreach (CompilerError error in results.Errors)
{
errors += string.Format("Error #{0}: {1}\n", error.ErrorNumber, error.ErrorText);
}
Console.Write(errors);
}
else
{
Assembly assembly = results.CompiledAssembly;
Type program = assembly.GetType("CTFGame.MyPlayer");
MethodInfo main = program.GetMethod("Main");
main.Invoke(null, null);
}
}
public static void SayHello()
{
Console.WriteLine("I'm awesome ><");
}
}
}
Now, Running the runtime loaded method 'Main' is a success, and the message "Hello world" is printed. The problem starts here: in the original code I have a method called "SayHello". I want to call this method from my runtime loaded code.
If I uncomment the "DoTurn" method, a compiler error will show in runtime:
Error #CS0103: The name 'Program' does not exist in the current context
My question is - is this possible, and how?
Putting the runtime loaded code in the same namespace doesn't help (and that makes sense), so what is the correct way to do that?
Thanks.

Adding a reference to the current assembly solved the problem:
CSharpCodeProvider provider = new CSharpCodeProvider();
CompilerParameters parameters = new CompilerParameters();
parameters.GenerateInMemory = true;
//The next line is the addition to the original code
parameters.ReferencedAssemblies.Add(Assembly.GetEntryAssembly().Location);
More about:
Compiling c# at runtime with user defined functions

Runtime compilation generates a file that can't be removed

I have this console type thing that accepts a line of C# code, wraps it up in some surrounding code and compiles it into an assembly. Then, I invoke the method from that assembly, output the result and that's it.
The problem is, the assembly needs to have a name so I can set it as a friend assembly so it could access the non-public classes. I named it "console".
Everything worked as expected but the problem is that I can't run a second script after one has finished because the file named "console" already exists in the directory and can't be overwritten.
I've tried Disposing of everything that has a Dispose method. I've tried manually deleting the file with File.Delete. Nothing helped.
So here's the code I'm using. I hope someone can help me.
CSharpCodeProvider provider = new CSharpCodeProvider();
var param = new CompilerParameters();
param.GenerateInMemory = false;
param.GenerateExecutable = false;
param.OutputAssembly = "console";
param.ReferencedAssemblies.Add("System.dll");
param.ReferencedAssemblies.Add("System.Core.dll");
param.ReferencedAssemblies.Add(Assembly.GetExecutingAssembly().Location);
var results = provider.CompileAssemblyFromSource(param,
#"
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
namespace FireflyGL
{
class DebugConsole
{
static void Run(StringWriter writer)
{
var stdOut = Console.Out;
Console.SetOut(writer);
" + input.Text + #"
Console.SetOut(stdOut);
}
}
}");
if (results.Errors.HasErrors)
{
for (int i = 0; i < results.Errors.Count; ++i)
{
PushText(results.Errors[i].ErrorText);
}
}
else
{
try
{
var writter = new StringWriter();
results.CompiledAssembly.GetType("FireflyGL.DebugConsole").GetMethod("Run", BindingFlags.Static | BindingFlags.NonPublic).Invoke(null, new object[] { writter });
PushText(writter.ToString());
history.Add(input.Text);
currentHistory = history.Count;
input.Text = "";
writter.Dispose();
}
catch (Exception)
{
}
}
provider.Dispose();
File.Delete(results.CompiledAssembly.Location);

You have to unload the assembly to get rid of all the references. Unfortunately, you can't do that. You can however unload an AppDomain and provided you reference your assembly in that AppDomain, it will be unloaded as well.
If you don't care about creating a memory leak, you could also just create unique names for your assembly (console1, console2 etc.)...

CSharpCodeProvider Compilation Performance

Is CompileAssemblyFromDom faster than CompileAssemblyFromSource?
It should be as it presumably bypasses the compiler front-end.

CompileAssemblyFromDom compiles to a .cs file which is then run through the normal C# compiler.
Example:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.CSharp;
using System.CodeDom;
using System.IO;
using System.CodeDom.Compiler;
using System.Reflection;
namespace CodeDomQuestion
{
class Program
{
private static void Main(string[] args)
{
Program p = new Program();
p.dotest("C:\\fs.exe");
}
public void dotest(string outputname)
{
CSharpCodeProvider cscProvider = new CSharpCodeProvider();
CompilerParameters cp = new CompilerParameters();
cp.MainClass = null;
cp.GenerateExecutable = true;
cp.OutputAssembly = outputname;
CodeNamespace ns = new CodeNamespace("StackOverflowd");
CodeTypeDeclaration type = new CodeTypeDeclaration();
type.IsClass = true;
type.Name = "MainClass";
type.TypeAttributes = TypeAttributes.Public;
ns.Types.Add(type);
CodeMemberMethod cmm = new CodeMemberMethod();
cmm.Attributes = MemberAttributes.Static;
cmm.Name = "Main";
cmm.Statements.Add(new CodeSnippetExpression("System.Console.WriteLine('f'zxcvv)"));
type.Members.Add(cmm);
CodeCompileUnit ccu = new CodeCompileUnit();
ccu.Namespaces.Add(ns);
CompilerResults results = cscProvider.CompileAssemblyFromDom(cp, ccu);
foreach (CompilerError err in results.Errors)
Console.WriteLine(err.ErrorText + " - " + err.FileName + ":" + err.Line);
Console.WriteLine();
}
}
}
which shows errors in a (now nonexistent) temp file:
) expected - c:\Documents and Settings\jacob\Local Settings\Temp\x59n9yb-.0.cs:17
; expected - c:\Documents and Settings\jacob\Local Settings\Temp\x59n9yb-.0.cs:17
Invalid expression term ')' - c:\Documents and Settings\jacob\Local Settings\Tem p\x59n9yb-.0.cs:17
So I guess the answer is "no"

I've tried finding the ultimate compiler call earlier and I gave up. There's quite a number of layers of interfaces and virtual classes for my patience.
I don't think the source reader part of the compiler ends up with a DOM tree, but intuitively I would agree with you. The work necessary to transform the DOM to IL should be much less than reading C# source code.