Could not find or load assembly \"tmpAssembly,

问题:

I am trying to use a dinamycally generated type as the source of one business rules editor called codeeffects (www.codeeffects.com), however I am getting this exception

Could not find or load assembly "tmpAssembly, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null". Error message: Could not load file or assembly 'tmpAssembly, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified. (Error S103)

The index action in the controller is:

[HttpGet]
        public ActionResult Index()
        {
            IMyInterface myObject = (IMyInterface)ObjectBuilder.CreateOurNewObject();
            Type t = myObject.GetType();
            ViewBag.Rule = RuleModel.Create(t);
            return View();
        }

and the method that creates the new object is.

public static object CreateOurNewObject()
        {
            string _xml = "<root>" +
                "<column name=\"Name\">Miron</column>" +
                "<column name=\"LastName\">Abramson</column>" +
                "<column name=\"Blog\">www.blog.mironabramson.com</column>" +
                "</root>";

            XmlDocument xmlDoc = new XmlDocument();
            xmlDoc.LoadXml(_xml);

            // create a dynamic assembly and module 
            AssemblyName assemblyName = new AssemblyName();
            assemblyName.Name = "tmpAssembly";
            System.Reflection.Emit.AssemblyBuilder assemblyBuilder = Thread.GetDomain().DefineDynamicAssembly(assemblyName, AssemblyBuilderAccess.Run);
            ModuleBuilder module = assemblyBuilder.DefineDynamicModule("tmpModule");

            // create a new type builder
            TypeBuilder typeBuilder = module.DefineType("BindableRowCellCollection", TypeAttributes.Public | TypeAttributes.Class);

            typeBuilder.AddInterfaceImplementation(typeof(IMyInterface));

            // Loop over the attributes that will be used as the properties names in out new type
            foreach (XmlNode node in xmlDoc.SelectSingleNode("root").ChildNodes)
            {
                string propertyName = node.Attributes["name"].Value;

                // Generate a private field
                FieldBuilder field = typeBuilder.DefineField("_" + propertyName, typeof(string), FieldAttributes.Private);
                // Generate a public property
                PropertyBuilder property =
                    typeBuilder.DefineProperty(propertyName,
                                     PropertyAttributes.None,
                                     typeof(string),
                                     new Type[] { typeof(string) });

                // The property set and property get methods require a special set of attributes:

                MethodAttributes GetSetAttr =
                    MethodAttributes.Public |
                    MethodAttributes.HideBySig;

                // Define the "get" accessor method for current private field.
                MethodBuilder currGetPropMthdBldr =
                    typeBuilder.DefineMethod("get_value",
                                               GetSetAttr,
                                               typeof(string),
                                               Type.EmptyTypes);

                // Intermediate Language stuff...
                ILGenerator currGetIL = currGetPropMthdBldr.GetILGenerator();
                currGetIL.Emit(OpCodes.Ldarg_0);
                currGetIL.Emit(OpCodes.Ldfld, field);
                currGetIL.Emit(OpCodes.Ret);

                // Define the "set" accessor method for current private field.
                MethodBuilder currSetPropMthdBldr =
                    typeBuilder.DefineMethod("set_value",
                                               GetSetAttr,
                                               null,
                                               new Type[] { typeof(string) });

                // Again some Intermediate Language stuff...
                ILGenerator currSetIL = currSetPropMthdBldr.GetILGenerator();
                currSetIL.Emit(OpCodes.Ldarg_0);
                currSetIL.Emit(OpCodes.Ldarg_1);
                currSetIL.Emit(OpCodes.Stfld, field);
                currSetIL.Emit(OpCodes.Ret);

                // Last, we must map the two methods created above to our PropertyBuilder to 
                // their corresponding behaviors, "get" and "set" respectively. 
                property.SetGetMethod(currGetPropMthdBldr);
                property.SetSetMethod(currSetPropMthdBldr);
            }

            // Generate our type
            Type generetedType = typeBuilder.CreateType();

            // Now we have our type. Let's create an instance from it:
            object generetedObject = Activator.CreateInstance(generetedType);

            // Loop over all the generated properties, and assign the values from our XML:
            PropertyInfo[] properties = generetedType.GetProperties();

            int propertiesCounter = 0;

            // Loop over the values that we will assign to the properties
            foreach (XmlNode node in xmlDoc.SelectSingleNode("root").ChildNodes)
            {
                string value = node.InnerText;
                properties[propertiesCounter].SetValue(generetedObject, value, null);
                propertiesCounter++;
            }

            //Yoopy ! Return our new genereted object.
            return generetedObject;
        }

回答1:

This happens because the RuleModel.Create(Type type) internally calls the Assembly.Load(string assemblyName) which looks for an assembly in a default search path, e.g. bin/, bin/assembly.dll/, .net temp paths, etc. I wish it'd simply use the passed type, but it doesn't. It tries to load it.

Make sure to call the AssemblyBuilder.Save() method to save the assembly first so that it can be loaded by the RuleModel later.

See my previous answer in How to use a dinamically generated object as the data source of CodeEffects generator