问题
Is it possible to compile and run C# code at runtime in the new .Net Core (better .Net Standard Platform)? I have seen some examples (.Net Framework), but they used NuGet packages that are not compatible with netcoreapp1.0 (.NETCoreApp,Version=v1.0)
回答1:
Option #1: Use the full C# compiler to compile an assembly, load it and then execute a method from it.
This requires the following packages as dependencies in your project.json:
"Microsoft.CodeAnalysis.CSharp": "1.3.0-beta1-20160429-01",
"System.Runtime.Loader": "4.0.0-rc2-24027",
Then you can use code like this:
var compilation = CSharpCompilation.Create("a")
.WithOptions(new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary))
.AddReferences(
MetadataReference.CreateFromFile(typeof(object).GetTypeInfo().Assembly.Location))
.AddSyntaxTrees(CSharpSyntaxTree.ParseText(
@"
using System;
public static class C
{
public static void M()
{
Console.WriteLine(""Hello Roslyn."");
}
}"));
var fileName = "a.dll";
compilation.Emit(fileName);
var a = AssemblyLoadContext.Default.LoadFromAssemblyPath(Path.GetFullPath(fileName));
a.GetType("C").GetMethod("M").Invoke(null, null);
Option #2: Use Roslyn Scripting. This will result in much simpler code, but currently requires more setup:
Create NuGet.config to get packages from the Roslyn nightly feed:
<?xml version="1.0" encoding="utf-8"?> <configuration> <packageSources> <add key="Roslyn Nightly" value="https://www.myget.org/F/roslyn-nightly/api/v3/index.json" /> </packageSources> </configuration>
Add the following package as a dependency to project.json (notice that this is package from today, you will need different version in the future):
"Microsoft.CodeAnalysis.CSharp.Scripting": "1.3.0-beta1-20160530-01",
You also need to import
dotnet
(obsolete "Target Framework Moniker", which is nevertheless still used by Roslyn):"frameworks": { "netcoreapp1.0": { "imports": "dotnet5.6" } }
Now you can finally use Scripting:
CSharpScript.EvaluateAsync(@"using System;Console.WriteLine(""Hello Roslyn."");").Wait();
回答2:
Just adding to @svick option one answer. If you want to keep the assembly in memory (rather than writing to a file) you can use the following method:
AssemblyLoadContext context = AssemblyLoadContext.Default;
Assembly assembly = context.LoadFromStream(ms);
This is different that in Net451 where the code is:
Assembly assembly = Assembly.Load(ms.ToArray());
My code targets both Net451 and Netstandard so I had to use directives to get around this problem. The full code example is here:
string code = CreateFunctionCode();
var syntaxTree = CSharpSyntaxTree.ParseText(code);
MetadataReference[] references = new MetadataReference[]
{
MetadataReference.CreateFromFile(typeof(object).GetTypeInfo().Assembly.Location),
MetadataReference.CreateFromFile(typeof(Hashtable).GetTypeInfo().Assembly.Location)
};
var compilation = CSharpCompilation.Create("Function.dll",
syntaxTrees: new[] { syntaxTree },
references: references,
options: new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary));
StringBuilder message = new StringBuilder();
using (var ms = new MemoryStream())
{
EmitResult result = compilation.Emit(ms);
if (!result.Success)
{
IEnumerable<Diagnostic> failures = result.Diagnostics.Where(diagnostic =>
diagnostic.IsWarningAsError ||
diagnostic.Severity == DiagnosticSeverity.Error);
foreach (Diagnostic diagnostic in failures)
{
message.AppendFormat("{0}: {1}", diagnostic.Id, diagnostic.GetMessage());
}
return new ReturnValue<MethodInfo>(false, "The following compile errors were encountered: " + message.ToString(), null);
}
else
{
ms.Seek(0, SeekOrigin.Begin);
#if NET451
Assembly assembly = Assembly.Load(ms.ToArray());
#else
AssemblyLoadContext context = AssemblyLoadContext.Default;
Assembly assembly = context.LoadFromStream(ms);
#endif
Type mappingFunction = assembly.GetType("Program");
_functionMethod = mappingFunction.GetMethod("CustomFunction");
_resetMethod = mappingFunction.GetMethod("Reset");
}
}
回答3:
Both previous answers didn't work for me in .NET Core 2.2 environment on Windows. More references are needed.
So with the help of https://stackoverflow.com/a/39260735/710069 solution, I have ended up with this code:
var dotnetCoreDirectory = System.Runtime.InteropServices.RuntimeEnvironment.GetRuntimeDirectory();
var compilation = CSharpCompilation.Create("LibraryName")
.WithOptions(new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary))
.AddReferences(
MetadataReference.CreateFromFile(typeof(object).GetTypeInfo().Assembly.Location),
MetadataReference.CreateFromFile(typeof(Console).GetTypeInfo().Assembly.Location),
MetadataReference.CreateFromFile(Path.Combine(dotnetCoreDirectory, "mscorlib.dll")),
MetadataReference.CreateFromFile(Path.Combine(dotnetCoreDirectory, "netstandard.dll")),
MetadataReference.CreateFromFile(Path.Combine(dotnetCoreDirectory, "System.Runtime.dll")))
.AddSyntaxTrees(CSharpSyntaxTree.ParseText(
@"public static class ClassName
{
public static void MethodName() => System.Console.WriteLine(""Hello C# Compilation."");
}"));
// Debug output. In case your environment is different it may show some messages.
foreach (var compilerMessage in compilation.GetDiagnostics())
Console.WriteLine(compilerMessage);
Than output library to file:
var fileName = "LibraryName.dll";
var emitResult = compilation.Emit(fileName);
if (emitResult.Success)
{
var assembly = AssemblyLoadContext.Default.LoadFromAssemblyPath(Path.GetFullPath(fileName));
assembly.GetType("ClassName").GetMethod("MethodName").Invoke(null, null);
}
or to memory stream:
using (var memoryStream = new MemoryStream())
{
var emitResult = compilation.Emit(memoryStream);
if (emitResult.Success)
{
memoryStream.Seek(0, SeekOrigin.Begin);
var context = AssemblyLoadContext.Default;
var assembly = context.LoadFromStream(memoryStream);
assembly.GetType("ClassName").GetMethod("MethodName").Invoke(null, null);
}
}
来源:https://stackoverflow.com/questions/37526165/compiling-and-running-code-at-runtime-in-net-core-1-0