Assembly not saving correctly
-
10-07-2019 - |
Question
I have some very simple code to generate an assembly and invoke a method on a contained type. The method gets called and runs correctly, however when I view the generated assembly using Reflector, I don't see the type.
Below is the sample code:
namespace ConsoleApplication2
{
class Proggy
{
public static void Main(string[] args)
{
var ab = AppDomain.CurrentDomain.DefineDynamicAssembly(
new AssemblyName() { Name = "MyAssembly" },
AssemblyBuilderAccess.RunAndSave);
var module = ab.DefineDynamicModule(ab.GetName().Name);
var typeBuilder = module.DefineType("MyType");
var ctr = typeBuilder.DefineConstructor(MethodAttributes.Public,
CallingConventions.Standard, Type.EmptyTypes);
var ilgc = ctr.GetILGenerator();
ilgc.Emit(OpCodes.Ldarg_0);
ilgc.Emit(OpCodes.Call, typeof(object).GetConstructor(Type.EmptyTypes));
ilgc.Emit(OpCodes.Ret);
var method = typeBuilder.DefineMethod("MyMethod", MethodAttributes.Public,
typeof(int), new[] { typeof(string) });
var ilg = method.GetILGenerator();
ilg.Emit(OpCodes.Ldarg_1);
ilg.EmitCall(OpCodes.Callvirt, typeof(string).GetProperty("Length").GetGetMethod(),
null);
ilg.Emit(OpCodes.Ret);
var type = typeBuilder.CreateType();
ab.Save("mytestasm.dll");
var inst = Activator.CreateInstance(type);
Console.WriteLine(type.InvokeMember("MyMethod", BindingFlags.InvokeMethod, null, inst,
new[] { "MyTestString" }));
Console.ReadLine();
}
}
}
and here is the corresponding disassembly from Reflector:
.assembly MyAssembly
{
.ver 0:0:0:0
.hash algorithm 0x00008004
}
.module RefEmit_OnDiskManifestModule
// MVID: {0B944140-58D9-430E-A867-DE0AD0A8701F}
// Target Runtime Version: v2.0.50727
... and ...
{
.class private auto ansi <Module>
{
}
}
Can anyone help me with getting the assembly properly saved?
Solution
The trick is to use a "persistable module" version of DefineDynamicModule method on the AssemblyBuilder instance. That is, instead of:
var module = ab.DefineDynamicModule(ab.GetName().Name);
use something like:
var module = ab.DefineDynamicModule(ab.GetName().Name, ab.GetName().Name + ".mod");
Thereafter the corresponding module appears in the assembly after saving.
OTHER TIPS
I am not sure why the type is not getting added.
Another way of doing this however is to dynamically create code by just passing in a string which contains your class code. I think this is a bit easier than the above way of doing it as you can just build up the code using a string builder and test in studio.
Here is the code i use to generate a dll:
print(" Microsoft.CSharp.CSharpCodeProvider objCodeProvider = new Microsoft.CSharp.CSharpCodeProvider();
string strCode = "using System;" + Environment.NewLine + "using System.Data;" + Environment.NewLine + "using DC.Common;" + Environment.NewLine + "" + Environment.NewLine + "using System.Data.SqlClient;" + Environment.NewLine + "using System.Configuration;" + Environment.NewLine + "" + Environment.NewLine + Environment.NewLine + BaseClassFile + Environment.NewLine + BaseManagerFile + Environment.NewLine;
string strSourceModule = BuilderSettings.ExportDir + "/" + BuilderSettings.ProjectName + "/" + "BaseFile.cs";
FileHelper.WriteAllText(strSourceModule, strCode);
FileHelper.WriteAllText(BuilderSettings.ExportDir + "/" + BuilderSettings.ProjectName + "/" + "test.txt", strCode);
ICodeCompiler icc = objCodeProvider.CreateCompiler();
string OutputPath = BuilderSettings.ExportDir + "/" + BuilderSettings.ProjectName + "/" + BuilderSettings.ProjectName + ".dll";
CompilerParameters parameters = new CompilerParameters();
CompilerResults results;
parameters.GenerateExecutable = false;
parameters.OutputAssembly = OutputPath;
parameters.GenerateInMemory = false;
parameters.IncludeDebugInformation = false;
//Add required assemblies
DynamicLinkLibraries.Clear();
//User defined
DynamicLinkLibraries.Add(@"d:\wwwroot\\DC.Common\bin\Debug\DC.Common.dll");
//System
DynamicLinkLibraries.Add("System.dll");
DynamicLinkLibraries.Add("System.Data.dll");
DynamicLinkLibraries.Add("mscorlib.dll");
DynamicLinkLibraries.Add("System.xml.dll");
DynamicLinkLibraries.Add("System.web.dll");
DynamicLinkLibraries.Add("System.configuration.dll");
//Any dynamic assembly adding must be done here
foreach (string strLibrary in DynamicLinkLibraries)
{
parameters.ReferencedAssemblies.Add(strLibrary);
}
results = icc.CompileAssemblyFromSource(parameters, strCode);
if (results.Errors.Count > 0)
{
//report any compilation errors
string strErrors = "Compilation failed:" + Environment.NewLine;
foreach (CompilerError oError in results.Errors)
{
strErrors = strErrors + "Line number " + oError.Line + ", Error Number: " + oError.ErrorNumber + ", '" + oError.ErrorText + ";";
}
throw new Exception("Error in CompileSourceCode(): " + Environment.NewLine + strErrors);
}
objCodeProvider = null;
icc = null;
parameters = null;");