How to use a dynamically generated object as a data source of a CodeEffects generator

Question

We use this component www.codeeffects.com, which allows us to create business rules based on the properties of an object.

The html of the view is as follows:

@{ ViewBag.Title = "Post Example"; Html.CodeEffects().Styles() .SetTheme(ThemeType.Gray) .Render(); } @using (Html.BeginForm("Evaluate", "Post", FormMethod.Post)) { <div class="area"> <h1 class="title">Post Example</h1> <div style="margin-top:10px;"> <span>Info:</span> <span style="color:Red;">@ViewBag.Message</span> </div> <div style="margin-top:10px;"> @{ Html.CodeEffects().RuleEditor() .Id("ruleEditor") .SaveAction("Save", "Post") .DeleteAction("Delete", "Post") .LoadAction("Load", "Post") .Mode(RuleType.Execution) .ContextMenuRules(ViewBag.ContextMenuRules) .ToolBarRules(ViewBag.ToolBarRules) .Rule(ViewBag.Rule) .Render(); } </div> </div> <div class="area"> <h1 class="title" style="margin-top:20px;">Rule Test Form</h1> @{ Html.RenderPartial("_PatientForm"); } </div> } @{ Html.CodeEffects().Scripts().Render(); } 

the action of the index in the controller is as follows:

  [HttpGet] public ActionResult Index() { ViewBag.Rule = RuleModel.Create(typeof(Patient)); return View(); } 

The Patient class is as follows:

 // External methods and actions [ExternalMethod(typeof(PatientService), "IsToday")] [ExternalAction(typeof(PatientService), "RequestInfo")] // Dynamic Menu Data Sources; details can be found at // http://codeeffects.com/Doc/Business-Rules-Dynamic-Menu-Data-Sources // The getEducationTypes() client-side function declared in /Views/Shared/_Layout.cshtml [Data("Education", "getEducationTypes")] // The List() method declared by the Physician class [Data("Physicians", typeof(Physician), "List")] public class Patient { // C-tor public Patient() { this.ID = Guid.Empty; this.Gender = Gender.Unknown; } // This property will not appear in the Rule Editor - Code Effects component ignores Guids. // Details at http://codeeffects.com/Doc/Business-Rules-Data-Types public Guid ID { get; set; } [Field(DisplayName = "First Name", Description = "Patient first name", Max = 30)] public string FirstName { get; set; } [Field(DisplayName = "Last Name", Max = 30, Description = "Patient last name")] public string LastName { get; set; } [Field(DisplayName = "Email Address", ValueInputType = ValueInputType.User, Max = 150, Description = "Email address of the patient")] public string Email { get; set; } [Field(DisplayName = "Date of Birth", DateTimeFormat = "MMM dd, yyyy")] public DateTime? DOB { get; set; } [Field(ValueInputType = ValueInputType.User, Description = "Patient gender")] public Gender Gender { get; set; } // This field uses the "Physicians" dynamic menu source (declared at class level) [Field(DisplayName = "Physician", DataSourceName = "Physicians", Description = "Patient primary physician")] public int PhysicianID { get; set; } // This field uses the "Education" client-side dynamic menu source (declared at class level) [Field(DisplayName = "Education", DataSourceName = "Education", Description = "Patient education level")] public int EducationTypeID { get; set; } [Field(Min = 0, Max = 200, Description = "Current pulse")] public int? Pulse { get; set; } [Field(Min = 0, Max = 200, DisplayName = "Systolic Pressure", Description = "Current systolic pressure")] public int? SystolicPressure { get; set; } [Field(Min = 0, Max = 200, DisplayName = "Diastolic Pressure", Description = "Current Diastolic pressure")] public int? DiastolicPressure { get; set; } [Field(Min = 0, Max = 110, Description = "Current temperature")] public decimal? Temperature { get; set; } [Field(DisplayName = "Headaches Box", Description = "Does the patient have frequent headaches?")] public bool Headaches { get; set; } [Field(DisplayName = "Allergies Box", Description = "Any allergies?")] public bool Allergies { get; set; } [Field(DisplayName = "Tobacco Box", Description = "Does the patient smoke?")] public bool Tobacco { get; set; } [Field(DisplayName = "Alcohol Box", Description = "Alcohol use?")] public bool Alcohol { get; set; } public Address Home { get; set; } public Address Work { get; set; } // This property is used to display outputs of rule actions [ExcludeFromEvaluation] public string Output { get; set; } [Method("Full Name", "Joins together patient first and last names")] public string FullName() { return string.Format("{0} {1}", this.FirstName, this.LastName); } // Empty overload of the Register method. // No Method attribute is needed here because its // display name is the same as its declared name. [Action(Description = "Registers new patient")] public void Register() { this.Output = "The patient has been registered"; } // Overload of the Register method that takes one param. // Both overloads can be used in Code Effects as two different actions // as long as their display names are different. [Action("Register with a Message", "Registers new patient with additional info")] public void Register([Parameter(ValueInputType.User, Description = "Output message")] string message) { this.Output = message; } } 

However, we want to create a dinamyc object constructed using reflection, a method I created:

  private 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); // 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 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; } 

How do we replace a row in an index action to use this object instead of a patient? typeof (object) will not work.

Answer 1

Using TypeBuilder , you can try to use an existing or custom interface for the generated type, and then use it as your type.

 typeBuilder.AddInterfaceImplementation(typeof(IMyInterface)); 

Now the object you created (in the example above) is of type IMyInterface , which you could use in your Index action:

 ViewBag.Rule = RuleModel.Create(typeof(IMyInterface)); 

Answer 2

Extract the part from the CreateOurNewObject () method that concerns the creation of the type. Name it CreateType (xml string).

Change AssemlbyBuilderAccess.Run to AssemblyBuilderAccess.RunAndSave. Then, once the type has been created, call assemblyBuilder.Save (). Save it in the place where Assembly.Load will find (for example, bin or one of the .net temporary directories) or any other place in the search path.

Use it to create a type and to create objects.

Then in the index call

 Type myType = CreateType(xml); RuleModel.Create(myType); 

If you are evaluating from the outside, be sure to use the same type (do not regenerate it each time). This means that you will need to download it first.

 Type myType = Assembly.Load(assemblyName); object myObject = Activator.CreateInstance(myType); //...populate myObject with necessary values based on your xml Evaluator ev = new Evaluator(myType, rule); bool result = ev.Evaluate(myObject); 

or you can use DynamicEvaluator which just calls myObject.GetType ()

 DynamicEvaluator ev = new DynamicEvaluator(rule); bool result = ev.Evaluate(myObject); 

That should work. The important part here is that you first save your assembly (it cannot be read from memory at the moment) and that it is in a folder that is part of the search path so Assembly.Load (name) can find it.