I’m working within .net8.0-windows. I’m trying to write a class to a module (dll) using Mono.Cecil. I used to use .netframework4.8. Unfortunately, until 9.0, .net doesn’t have the ability to save/persist the assemblies.

This class has 2 custom attributes on it. The first attribute has a constructor with a single string argument – no problems here. All works as expected. The second attribute has a constructor with a single enum argument.

The expected outcome should look like this:

  [CustomAttributeType1("someStringArgument")]
  [CustomAttributeType2(MyEnum.SomeValue)]
  public class MyCustomClass : MyCustomClassBase
  {
     ...
  }

The actual output looks like so:

  [CustomAttributeType1("someStringArgument")]
  [CustomAttributeType2]
  public class MyCustomClass : MyCustomClassBase
  {
     ...
  }

Essentially, the constructor is being posted inside the attribute with no arguments or even parentheses.

The code I’m using for CustomAttributeType2 is as follows:

...
assembly/module defined first
...


var enumType = module.ImportReference(typeof(MyEnum));
var attrType2Ctor = module.ImportReference(typeof(CustomAttributeType2).GetConstructor(new Type[] { typeof(MyEnum) }));
var customAttr2 = new CustomAttribute(attrType2Ctor);
customAttr2.ConstructorArguments.Add(new CustomAttributeArgument(enumType, MyEnum.SomeValue));
typeDefinition.CustomAttributes.Add(customAttr2);

I’ve also tried the following for the constructor argument:

customAttr2.ConstructorArguments.Add(new CustomAttributeArgument(enumType, (int)MyEnum.SomeValue));

Any advice would be appreciated.