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  • C# asp.net EF MVC postgresql error 23505: Duplicate key violates unique constraint

    - by user2721755
    EDIT: It was issue with database table - dropping and recreating table id column did the work. Problem solved. I'm trying to build web application, that is connected to postgresql database. Results are displaying in view with Kendo UI. When I'm trying to add new row (with Kendo UI 'Add new record' button), I get error 23505: 'Duplicate key violates unique constraint'. My guess is, that EF takes id to insert from the beginning, not the last one, because after 35 (it's number of rows in table) tries - and errors - adding works perfectly. Can someone help me to understand, what's wrong? Model: using System.ComponentModel.DataAnnotations; using System.ComponentModel.DataAnnotations.Schema; namespace MainConfigTest.Models { [Table("mainconfig", Schema = "public")] public class Mainconfig { [Column("id")] [Key] [Editable(false)] public int Id { get; set; } [Column("descr")] [Editable(true)] public string Descr { get; set; } [Column("hibversion")] [Required] [Editable(true)] public long Hibversion { get; set; } [Column("mckey")] [Required] [Editable(true)] public string Mckey { get; set; } [Column("valuexml")] [Editable(true)] public string Valuexml { get; set; } [Column("mcvalue")] [Editable(true)] public string Mcvalue { get; set; } } } Context: using System.Data.Entity; namespace MainConfigTest.Models { public class MainConfigContext : DbContext { public DbSet<Mainconfig> Mainconfig { get; set; } } } Controller: namespace MainConfigTest.Controllers { public class MainConfigController : Controller { #region Properties private Models.MainConfigContext db = new Models.MainConfigContext(); private string mainTitle = "Mainconfig (Kendo UI)"; #endregion #region Initialization public MainConfigController() { ViewBag.MainTitle = mainTitle; } #endregion #region Ajax [HttpGet] public JsonResult GetMainconfig() { int take = HttpContext.Request["take"] == null ? 5 : Convert.ToInt32(HttpContext.Request["take"]); int skip = HttpContext.Request["skip"] == null ? 0 : Convert.ToInt32(HttpContext.Request["skip"]); Array data = (from Models.Mainconfig c in db.Mainconfig select c).OrderBy(c => c.Id).ToArray().Skip(skip).Take(take).ToArray(); return Json(new Models.MainconfigResponse(data, db.Mainconfig.Count()), JsonRequestBehavior.AllowGet); } [HttpPost] public JsonResult Create() { try { Mainconfig itemToAdd = new Mainconfig() { Descr = Convert.ToString(HttpContext.Request["Descr"]), Hibversion = Convert.ToInt64(HttpContext.Request["Hibversion"]), Mckey = Convert.ToString(HttpContext.Request["Mckey"]), Valuexml = Convert.ToString(HttpContext.Request["Valuexml"]), Mcvalue = Convert.ToString(HttpContext.Request["Mcvalue"]) }; db.Mainconfig.Add(itemToAdd); db.SaveChanges(); return Json(new { Success = true }); } catch (InvalidOperationException ex) { return Json(new { Success = false, msg = ex }); } } //other methods } } Kendo UI script in view: <script type="text/javascript"> $(document).ready(function () { $("#config-grid").kendoGrid({ sortable: true, pageable: true, scrollable: false, toolbar: ["create"], editable: { mode: "popup" }, dataSource: { pageSize: 5, serverPaging: true, transport: { read: { url: '@Url.Action("GetMainconfig")', dataType: "json" }, update: { url: '@Url.Action("Update")', type: "Post", dataType: "json", complete: function (e) { $("#config-grid").data("kendoGrid").dataSource.read(); } }, destroy: { url: '@Url.Action("Delete")', type: "Post", dataType: "json" }, create: { url: '@Url.Action("Create")', type: "Post", dataType: "json", complete: function (e) { $("#config-grid").data("kendoGrid").dataSource.read(); } }, }, error: function (e) { if(e.Success == false) { this.cancelChanges(); } }, schema: { data: "Data", total: "Total", model: { id: "Id", fields: { Id: { editable: false, nullable: true }, Descr: { type: "string"}, Hibversion: { type: "number", validation: {required: true,}, }, Mckey: { type: "string", validation: { required: true, }, }, Valuexml:{ type: "string"}, Mcvalue: { type: "string" } } } } }, //end DataSource // generate columns etc. Mainconfig table structure: id serial NOT NULL, descr character varying(200), hibversion bigint NOT NULL, mckey character varying(100) NOT NULL, valuexml character varying(8000), mcvalue character varying(200), CONSTRAINT mainconfig_pkey PRIMARY KEY (id), CONSTRAINT mainconfig_mckey_key UNIQUE (mckey) Any help will be appreciated.

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  • iPhone Development - Query related records using CoreData

    - by Mustafa
    I have a case where i have three entities with one-to-many and one-to-many relationships: Entity A (Entity B relationhip), Entity B (Entity A relationship, Entity C relationship), Entity C (Entity B relationhip) I have the reference of Entity A, and now i want to fetch all the related Entity C records. How can i do that? (with least amount of code) Edit: Here's another way to put it. Can we perform joins with CoreData. For example, (and this is a very crude example), We have a following entity-relationship: Grand Parent (1)---(m) Parent Parent (1)---(m) Child So, now if i have "Albert" the Grand Parent, and i want to get all his grand children, how can i do that?

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  • Different setter behavior between DbContext and ObjectContext

    - by Paul
    (This is using EntityFramework 4.2 CTP) I haven't found any references to this on the web yet, although it's likely I'm using the wrong terminology while searching. There's also a very likely scenario where this is 100% expected behavior, just looking for confirmation and would rather not dig through the tt template (still new to this). Assuming I have a class with a boolean field called Active and I have one row that already has this value set to true. I have code that executes to set said field to True regardless of it's existing value. If I use DbContext to update the value to True no update is made. If I use ObjectContext to update the value an update is made regardless of the existing value. This is happening in the exact same EDMX, all I did was change the code generation template from DbContext to EntityObject. Update: Ok, found the confirmation I was looking for...consider this a dupe...next time I'll do MOAR SEARCHING! Entity Framework: Cancel a property change if no change in value ** Update 2: ** Problem: the default tt template wraps the "if (this != value)" in the setter with "if (iskey), so only primarykey fields receive this logic. Solution: it's not the most graceful thing, but I removed this check...we'll see how it pans out in real usage. I included the entire tt template, my changes are denoted with "**"... //////// //////// Write SimpleType Properties. //////// private void WriteSimpleTypeProperty(EdmProperty simpleProperty, CodeGenerationTools code) { MetadataTools ef = new MetadataTools(this); #> /// <summary> /// <#=SummaryComment(simpleProperty)#> /// </summary><#=LongDescriptionCommentElement(simpleProperty, 1)#> [EdmScalarPropertyAttribute(EntityKeyProperty= <#=code.CreateLiteral(ef.IsKey(simpleProperty))#>, IsNullable=<#=code.CreateLiteral(ef.IsNullable(simpleProperty))#>)] [DataMemberAttribute()] <#=code.SpaceAfter(NewModifier(simpleProperty))#><#=Accessibility.ForProperty(simpleProperty)#> <#=MultiSchemaEscape(simpleProperty.TypeUsage, code)#> <#=code.Escape(simpleProperty)#> { <#=code.SpaceAfter(Accessibility.ForGetter(simpleProperty))#>get { <#+ if (ef.ClrType(simpleProperty.TypeUsage) == typeof(byte[])) { #> return StructuralObject.GetValidValue(<#=code.FieldName(simpleProperty)#>); <#+ } else { #> return <#=code.FieldName(simpleProperty)#>; <#+ } #> } <#=code.SpaceAfter(Accessibility.ForSetter((simpleProperty)))#>set { <#+ **//if (ef.IsKey(simpleProperty)) **//{ if (ef.ClrType(simpleProperty.TypeUsage) == typeof(byte[])) { #> if (!StructuralObject.BinaryEquals(<#=code.FieldName(simpleProperty)#>, value)) <#+ } else { #> if (<#=code.FieldName(simpleProperty)#> != value) <#+ } #> { <#+ PushIndent(CodeRegion.GetIndent(1)); **//} #> <#=ChangingMethodName(simpleProperty)#>(value); ReportPropertyChanging("<#=simpleProperty.Name#>"); <#=code.FieldName(simpleProperty)#> = <#=CastToEnumType(simpleProperty.TypeUsage, code)#>StructuralObject.SetValidValue(<#=CastToUnderlyingType(simpleProperty.TypeUsage, code)#>value<#=OptionalNullableParameterForSetValidValue(simpleProperty, code)#>, "<#=simpleProperty.Name#>"); ReportPropertyChanged("<#=simpleProperty.Name#>"); <#=ChangedMethodName(simpleProperty)#>(); <#+ //if (ef.IsKey(simpleProperty)) //{ PopIndent(); #> } <#+ //} #> } }

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  • Can't get results from a IQueryable.

    - by StackPointer
    Hi! I have the following code in Linq to Entity: var policy= from pol in conn.Policy where pol.Product.DESCRIPTION=="someProduct" SELECT pol; Then, the table Policy, has some dependencies for a table called Entity. If I do this: foreach(Policy p in policy){ if(!p.Entity.IsLoaded) p.Entity.Load(); IEnumerable<Entity> entities= from ent in p.Entity Where ent.EntityType.DESCRIPTION=="SomeEntityType" select ent; Console.Writeline(entities.ElementAt(0).NAME); } It says, "Object not set to an instance", but if I do: foreach(Policy p in policy){ if(!p.Entity.IsLoaded) p.Entity.Load(); foreach(Entity et in p.Entity)Console.Write(et.NAME); } It works! Can anyone tell me why? Thank you, Best regards.

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  • ASP.net MVC DropLownList db.SaveChanges not saving selection

    - by WMIF
    I have looked through a ton of tutorials and suggestions on how to work with DropDownList in MVC. I was able to get most of it working, but the selected item is not saving into the database. I am using MVC 3 and Razor for the view. My DropDownList is getting created with the correct values and good looking HTML. When I set a breakpoint, I can see the correct selected item ID in the model getting sent to controller. When the view goes back to the index, the DropDownList value is not set. The other values save just fine. Here are the related views. The DropDownList is displaying a list of ColorModel names as text with the ID as the value. public class ItemModel { [Key] public int ItemID { get; set; } public string Name { get; set; } public string Description { get; set; } public virtual ColorModel Color { get; set; } } public class ItemEditViewModel { public int ItemID { get; set; } public string Name { get; set; } public string Description { get; set; } public int ColorID { get; set; } public IEnumerable<SelectListItem> Colors { get; set; } } public class ColorModel { [Key] public int ColorID { get; set; } public string Name { get; set; } public virtual IList<ItemModel> Items { get; set; } } Here are the controller actions. public ActionResult Edit(int id) { ItemModel itemmodel = db.Items.Find(id); ItemEditViewModel itemEditModel; itemEditModel = new ItemEditViewModel(); itemEditModel.ItemID = itemmodel.ItemID; if (itemmodel.Color != null) { itemEditModel.ColorID = itemmodel.Color.ColorID; } itemEditModel.Description = itemmodel.Description; itemEditModel.Name = itemmodel.Name; itemEditModel.Colors = db.Colors .ToList() .Select(x => new SelectListItem { Text = x.Name, Value = x.ColorID.ToString() }); return View(itemEditModel); } [HttpPost] public ActionResult Edit(ItemEditViewModel itemEditModel) { if (ModelState.IsValid) { ItemModel itemmodel; itemmodel = new ItemModel(); itemmodel.ItemID = itemEditModel.ItemID; itemmodel.Color = db.Colors.Find(itemEditModel.ColorID); itemmodel.Description = itemEditModel.Description; itemmodel.Name = itemEditModel.Name; db.Entry(itemmodel).State = EntityState.Modified; db.SaveChanges(); return RedirectToAction("Index"); } return View(itemEditModel); } The view has this for the DropDownList, and the others are just EditorFor(). @Html.DropDownListFor(model => model.ColorID, Model.Colors, "Select a Color") When I set the breakpoint on the db.Color.Find(...) line, I show this in the Locals window for itemmodel.Color: {System.Data.Entity.DynamicProxies.ColorModel_0EB80C07207CA5D88E1A745B3B1293D3142FE2E644A1A5202B90E5D2DAF7C2BB} When I expand that line, I can see the ColorID that I chose from the dropdown box, but it does not save into the database.

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  • Trouble with Code First DatabaseGenerated Composite Primary Key

    - by Nick Fleetwood
    This is a tad complicated, and please, I know all the arguments against natural PK's, so we don't need to have that discussion. using VS2012/MVC4/C#/CodeFirst So, the PK is based on the date and a corresponding digit together. So, a few rows created today would be like this: 20131019 1 20131019 2 And one created tomorrow: 20131020 1 This has to be automatically generated using C# or as a trigger or whatever. The user wouldn't input this. I did come up with a solution, but I'm having problems with it, and I'm a little stuck, hence the question. So, I have a model: public class MainOne { //[Key] //public int ID { get; set; } [Key][Column(Order=1)] [DatabaseGenerated(DatabaseGeneratedOption.None)] public string DocketDate { get; set; } [Key][Column(Order=2)] [DatabaseGenerated(DatabaseGeneratedOption.None)] public string DocketNumber { get; set; } [StringLength(3, ErrorMessage = "Corp Code must be three letters")] public string CorpCode { get; set; } [StringLength(4, ErrorMessage = "Corp Code must be four letters")] public string DocketStatus { get; set; } } After I finish the model, I create a new controller and views using VS2012 scaffolding. Then, what I'm doing is debugging to create the database, then adding the following instead of trigger after Code First creates the DB [I don't know if this is correct procedure]: CREATE TRIGGER AutoIncrement_Trigger ON [dbo].[MainOnes] instead OF INSERT AS BEGIN DECLARE @number INT SELECT @number=COUNT(*) FROM [dbo].[MainOnes] WHERE [DocketDate] = CONVERT(DATE, GETDATE()) INSERT INTO [dbo].[MainOnes] (DocketDate,DocketNumber,CorpCode,DocketStatus) SELECT (CONVERT(DATE, GETDATE ())),(@number+1),inserted.CorpCode,inserted.DocketStatus FROM inserted END And when I try to create a record, this is the error I'm getting: The changes to the database were committed successfully, but an error occurred while updating the object context. The ObjectContext might be in an inconsistent state. Inner exception message: The object state cannot be changed. This exception may result from one or more of the primary key properties being set to null. Non-Added objects cannot have null primary key values. See inner exception for details. Now, what's interesting to me, is that after I stop debugging and I start again, everything is perfect. The trigger fired perfectly, so the composite PK is unique and perfect, and the data in other columns is intact. My guess is that EF is confused by the fact that there is seemingly no value for the PK until AFTER an insert command is given. Also, appearing to back this theory, is that when I try to edit on of the rows, in debug, I get the following error: The number of primary key values passed must match number of primary key values defined on the entity. Same error occurs if I try to pull the 'Details' or 'Delete' function. Any solution or ideas on how to pull this off? I'm pretty open to anything, even creating a hidden int PK. But it would seem redundant. EDIT 21OCT13 [HttpPost] public ActionResult Create(MainOne mainone) { if (ModelState.IsValid) { var countId = db.MainOnes.Count(d => d.DocketDate == mainone.DocketNumber); //assuming that the date field already has a value mainone.DocketNumber = countId + 1; //Cannot implicitly convert type int to string db.MainOnes.Add(mainone); db.SaveChanges(); return RedirectToAction("Index"); } return View(mainone); } EDIT 21OCT2013 FINAL CODE SOLUTION For anyone like me, who is constantly searching for clear and complete solutions. if (ModelState.IsValid) { String udate = DateTime.UtcNow.ToString("yyyy-MM-dd"); mainone.DocketDate = udate; var ddate = db.MainOnes.Count(d => d.DocketDate == mainone.DocketDate); //assuming that the date field already has a value mainone.DocketNumber = ddate + 1; db.MainOnes.Add(mainone); db.SaveChanges(); return RedirectToAction("Index"); }

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  • Best datastructure for frequently queried list of objects

    - by panzerschreck
    Hello, I have a list of objects say, List. The Entity class has an equals method,on few attributes ( business rule ) to differentiate one Entity object from the other. The task that we usually carry out on this list is to remove all the duplicates something like this : List<Entity> noDuplicates = new ArrayList<Entity>(); for(Entity entity: lstEntities) { int indexOf = noDuplicates.indexOf(entity); if(indexOf >= 0 ) { noDuplicates.get(indexOf).merge(entity); } else { noDuplicates.add(entity); } } Now, the problem that I have been observing is that this part of the code, is slowing down considerably as soon as the list has objects more than 10000.I understand arraylist is doing a o(N) search. Is there a faster alternative, using HashMap is not an option, because the entity's uniqueness is built upon 4 of its attributes together, it would be tedious to put in the key itself into the map ? will sorted set help in faster querying ? Thanks

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  • Funnel Visualisation not showing drop out in steps

    - by cjk
    I have a site where users will follow this path (hopefully): mysite.com/entity mysite.com/entity/pay mysite.com/entity/pay/details mysite.com/entity/pay/confirmation mysite.com/entity/pay/payment mysite.com/entity/paymentsuccessful?lotsofuniquestuff The entity section could be any one of a multitude of entries, but once the user is on a journey it will stay consistent. I have a goal set up for this as a regular expression, with the match being .*PaymentSuccessful.*. This detects goal successes perfectly (as checked with data stored by the site directly). I have set the following steps within the goal: /[a-zA-Z0-9]+/pay /[a-zA-Z0-9]+/pay/details /[a-zA-Z0-9]+/pay/confirmation /[a-zA-Z0-9]+/pay/payment My funnel detects entry into the funnel (e.g. 47 users) of which say 10 complete the funnel. However, all drop offs are after the first step, even though the exist page is listed as the second step! My data also suggests users are getting further in the funnel before failing to reach the goal. What have I done wrong?

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  • StoreGeneratedPattern T4 EntityFramework concern

    - by LoganWolfer
    Hi everyone, Here's the situation : I use SQL Server 2008 R2, SQL Replication, Visual Studio 2010, EntityFramework 4, C# 4. The course-of-action from our DBA is to use a rowguid column for SQL Replication to work with our setup. These columns need to have a StoreGeneratedPattern property set to Computed on every one of these columns. The problem : Every time the T4 template regenerate our EDMX (ADO.NET Entity Data Model) file (for example, when we update it from our database), I need to go manually in the EDMX XML file to add this property to every one of them. It has to go from this : <Property Name="rowguid" Type="uniqueidentifier" Nullable="false" /> To this : <Property Name="rowguid" Type="uniqueidentifier" Nullable="false" StoreGeneratedPattern="Computed"/> The solution : I'm trying to find a way to customize an ADO.NET EntityObject Generator T4 file to generate a StoreGeneratedPattern="Computed" to every rowguid that I have. I'm fairly new to T4, I only did customization to AddView and AddController T4 templates for ASP.NET MVC 2, like List.tt for example. I've looked through the EF T4 file, and I can't seem to find through this monster where I could do that (and how). My best guess is somewhere in this part of the file, line 544 to 618 of the original ADO.NET EntityObject Generator T4 file : //////// //////// Write PrimitiveType Properties. //////// private void WritePrimitiveTypeProperty(EdmProperty primitiveProperty, CodeGenerationTools code) { MetadataTools ef = new MetadataTools(this); #> /// <summary> /// <#=SummaryComment(primitiveProperty)#> /// </summary><#=LongDescriptionCommentElement(primitiveProperty, 1)#> [EdmScalarPropertyAttribute(EntityKeyProperty=<#=code.CreateLiteral(ef.IsKey(primitiveProperty))#>, IsNullable=<#=code.CreateLiteral(ef.IsNullable(primitiveProperty))#>)] [DataMemberAttribute()] <#=code.SpaceAfter(NewModifier(primitiveProperty))#><#=Accessibility.ForProperty(primitiveProperty)#> <#=code.Escape(primitiveProperty.TypeUsage)#> <#=code.Escape(primitiveProperty)#> { <#=code.SpaceAfter(Accessibility.ForGetter(primitiveProperty))#>get { <#+ if (ef.ClrType(primitiveProperty.TypeUsage) == typeof(byte[])) { #> return StructuralObject.GetValidValue(<#=code.FieldName(primitiveProperty)#>); <#+ } else { #> return <#=code.FieldName(primitiveProperty)#>; <#+ } #> } <#=code.SpaceAfter(Accessibility.ForSetter((primitiveProperty)))#>set { <#+ if (ef.IsKey(primitiveProperty)) { if (ef.ClrType(primitiveProperty.TypeUsage) == typeof(byte[])) { #> if (!StructuralObject.BinaryEquals(<#=code.FieldName(primitiveProperty)#>, value)) <#+ } else { #> if (<#=code.FieldName(primitiveProperty)#> != value) <#+ } #> { <#+ PushIndent(CodeRegion.GetIndent(1)); } #> <#=ChangingMethodName(primitiveProperty)#>(value); ReportPropertyChanging("<#=primitiveProperty.Name#>"); <#=code.FieldName(primitiveProperty)#> = StructuralObject.SetValidValue(value<#=OptionalNullableParameterForSetValidValue(primitiveProperty, code)#>); ReportPropertyChanged("<#=primitiveProperty.Name#>"); <#=ChangedMethodName(primitiveProperty)#>(); <#+ if (ef.IsKey(primitiveProperty)) { PopIndent(); #> } <#+ } #> } } private <#=code.Escape(primitiveProperty.TypeUsage)#> <#=code.FieldName(primitiveProperty)#><#=code.StringBefore(" = ", code.CreateLiteral(primitiveProperty.DefaultValue))#>; partial void <#=ChangingMethodName(primitiveProperty)#>(<#=code.Escape(primitiveProperty.TypeUsage)#> value); partial void <#=ChangedMethodName(primitiveProperty)#>(); <#+ } Any help would be appreciated. Thanks in advance. EDIT : Didn't find answer to this problem yet, if anyone have ideas to automate this, would really be appreciated.

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  • How to display and update data in MVC2

    - by Picflight
    Table Product Product Id Product Name Table ProductSupplier ProductSupplierId ProductId SupplierId Table Supplier SupplierId SupplierName I have the above 3 tables in my database, ProductSupplier is the lookup table. Each Product can have many suppliers. I am using Entity Framework. Using Web Forms it was fairly easy to display a Product on a web page and bind a repeater with the suppliers information. Also, with Web Forms it was easy to Add new Product and suppliers, the linkage seemed easy. How do you do this sort of functionality in MVC? In the Create View below, I want to be able to Add the Supplier as well. Is there a better approach that I might be missing here? This is how I did it with Web Forms. Beyond the code below I am totally lost. I can show data in a list and also display the Suppliers for each Product, but how do I Add and Edit. Should I break it into different views? With Web Forms I could do it all in one page. namespace MyProject.Mvc.Models { [MetadataType(typeof(ProductMetaData))] public partial class Product { public Product() { // Initialize Product this.CreateDate = System.DateTime.Now; } } public class ProductMetaData { [Required(ErrorMessage = "Product name is required")] [StringLength(50, ErrorMessage = "Product name must be under 50 characters")] public object ProductName { get; set; } [Required(ErrorMessage = "Description is required")] public object Description { get; set; } } public class ProductFormViewModel { public Product Product { get; private set; } public IEnumerable<ProductSupplier> ProductSupplier { get; private set; } public ProductFormViewModel() { Product = new Product(); } public ProductFormViewModel(Product product) { Product = product; ProductSupplier = product.ProductSupplier; } } } ProductRepository public Product GetProduct(int id) { var p = db.Product.FirstOrDefault(por => por.ProductId == id); p.ProductSupplier.Attach(p.ProductSupplier.CreateSourceQuery().Include("Product").ToList()); return p; } Product Create View <%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<MyProject.Mvc.Models.ProductFormViewModel>" %> <%= Html.ValidationSummary("Please correct the errors and try again.") %> <% using (Html.BeginForm()) {%> <fieldset> <legend>Fields</legend> <div class="editor-label"> <%= Html.LabelFor(model => model.Product.ProductId) %> </div> <div class="editor-field"> <%= Html.TextBoxFor(model => model.Product.ProductId) %> <%= Html.ValidationMessageFor(model => model.Product.ProductId) %> </div> <div class="editor-label"> <%= Html.LabelFor(model => model.Product.ProductName) %> </div> <div class="editor-field"> <%= Html.TextBoxFor(model => model.Product.ProductName) %> <%= Html.ValidationMessageFor(model => model.Product.ProductName) %> </div> <div class="editor-label"> <%= Html.LabelFor(model => model.Product.Description) %> </div> <div class="editor-field"> <%= Html.TextBoxFor(model => model.Product.Description) %> <%= Html.ValidationMessageFor(model => model.Product.Description) %> </div> <p> <input type="submit" value="Create" /> </p> </fieldset> <% } %>

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  • A column ID occurred more than once in the specification

    - by Puzzle84
    Recently i've picked up my EF 4.1 / MVC 3 project again and started building in actual frontend capabilities. Now i'm developing a "simple" message system but upon going to that page i get the error as stated in the title EDIT It creates the database just not the models. Stack trace: [NullReferenceException: Object reference not set to an instance of an object.] ASP._Page_Views_Inbox_Index_cshtml.Execute() in c:\Development\MVC\DOCCL\Views\Inbox\Index.cshtml:18 System.Web.WebPages.WebPageBase.ExecutePageHierarchy() +197 System.Web.Mvc.WebViewPage.ExecutePageHierarchy() +81 System.Web.WebPages.StartPage.RunPage() +17 System.Web.WebPages.StartPage.ExecutePageHierarchy() +62 System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage) +76 System.Web.Mvc.RazorView.RenderView(ViewContext viewContext, TextWriter writer, Object instance) +222 System.Web.Mvc.BuildManagerCompiledView.Render(ViewContext viewContext, TextWriter writer) +115 System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context) +295 System.Web.Mvc.ControllerActionInvoker.InvokeActionResult(ControllerContext controllerContext, ActionResult actionResult) +13 System.Web.Mvc.<c_DisplayClass1c.b_19() +23 System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilter(IResultFilter filter, ResultExecutingContext preContext, Func1 continuation) +242 System.Web.Mvc.<>c__DisplayClass1e.<InvokeActionResultWithFilters>b__1b() +21 System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList1 filters, ActionResult actionResult) +177 System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName) +324 System.Web.Mvc.Controller.ExecuteCore() +106 System.Web.Mvc.ControllerBase.Execute(RequestContext requestContext) +91 System.Web.Mvc.ControllerBase.System.Web.Mvc.IController.Execute(RequestContext requestContext) +10 System.Web.Mvc.<c_DisplayClassb.b_5() +34 System.Web.Mvc.Async.<c_DisplayClass1.b_0() +19 System.Web.Mvc.Async.<c_DisplayClass81.<BeginSynchronous>b__7(IAsyncResult _) +10 System.Web.Mvc.Async.WrappedAsyncResult1.End() +62 System.Web.Mvc.<c_DisplayClasse.b_d() +48 System.Web.Mvc.SecurityUtil.b_0(Action f) +7 System.Web.Mvc.SecurityUtil.ProcessInApplicationTrust(Action action) +22 System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +60 System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) +9 System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +9478661 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +178 InnerException : {"A column ID occurred more than once in the specification."} The recently added code is. Controller: // // GET: /Inbox/Index/5/1 public ActionResult Index(int? Id, int Page = 1) { try { const int pageSize = 10; var messages = from m in horseTracker.Messages where m.ReceiverId.Equals(Id) select m; var paginatedMessages = new PaginatedList<Message>(messages, Page, pageSize); return View(paginatedMessages); } catch (Exception ex) { } return View(); } Models public class Message { [Key] public int Id { get; set; } [Required(ErrorMessage = "Subject is required")] [Display(Name = "Subject")] public string Subject { get; set; } [Required(ErrorMessage = "Message is required")] [Display(Name = "Message")] public string Content { get; set; } [Required] [Display(Name = "Date")] public DateTime Created { get; set; } public Boolean Read { get; set; } [Required(ErrorMessage = "Can't create a message without a user")] public int SenderId { get; set; } public virtual User Sender { get; set; } [Required(ErrorMessage = "Please pick a recipient")] public int ReceiverId { get; set; } public virtual User Receiver { get; set; } } public class User { [Key] public int Id { get; set; } [Required] [Display(Name = "Username")] public string UserName { get; set; } [Required] [Display(Name = "First Name")] public string FirstName { get; set; } [Required] [Display(Name = "Last Name")] public string LastName { get; set; } [Required] [Display(Name = "E-Mail")] public string Email { get; set; } [Required] [Display(Name = "Password")] public string Password { get; set; } [Required] [Display(Name = "Country")] public string Country { get; set; } public string EMail { get; set; } //Races public virtual ICollection<Message> Messages { get; set; } } modelBuilder.Entity<User>() .HasMany(u => u.Messages) .WithRequired(m => m.Receiver) .HasForeignKey(m => m.ReceiverId) .WillCascadeOnDelete(false); Anyone have a clue on why i might be getting that error? Before i added these classes it was working fine.

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  • Splitting a tetris game apart - where to put time-management?

    - by nightcracker
    I am creating a tetris game in C++ & SDL, and I'm trying to do it "good" by making it object-oriented and keeping scopes small. So far I have the following structure: A main with some lowlevel SDL set up and handling input A game class that keeps track of score and provides the interface for main (move block down, etc) A map class that keeps track of the current game field, which blocks are where. Used by the game class. A block class that consists of the current falling block, used by game. A renderer class abstracting low level SDL to a format where you render "tetris blocks". Used by map and block. Now I have a though time where to place the time-management of this game. For example, where should be decided when a block bumps the bottom of the screen how long it takes the current block locks in place and a new block spawns? I also have an other unrelated question, is there some place where you can find some standard data on tetris like standard score tables, rulesets, timings, etc?

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  • Splitting a tetris game apart - where to put time-management?

    - by nightcracker
    I am creating a tetris game in C++ & SDL, and I'm trying to do it "good" by making it object-oriented and keeping scopes small. So far I have the following structure: A main with some lowlevel SDL set up and handling input A game class that keeps track of score and provides the interface for main (move block down, etc) A map class that keeps track of the current game field, which blocks are where. Used by the game class. A block class that consists of the current falling block, used by game. A renderer class abstracting low level SDL to a format where you render "tetris blocks". Used by map and block. Now I have a though time where to place the time-management of this game. For example, where should be decided when a block bumps the bottom of the screen how long it takes the current block locks in place and a new block spawns? I also have an other unrelated question, is there some place where you can find some standard data on tetris like standard score tables, rulesets, timings, etc?

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  • What options are there for splitting UI layout from code logic using a markup language?

    - by Daenyth
    What tools similar to GWT's UIBinder exist in other languages? By this I mean a system where you can define your UI layout in a markup language (preferably html+css) and attach the functionality to the layout using the code. I'm most interested in anything for python, but answers in other languages would interest me as well. I'm interested because the benefits of having a non-programmer work directly on the layout without needing to touch the code and adjust a bunch of UI toolkit method calls is very productive. I'm aware of Flex for flash, but is there anything else out there? What search terms might I use to find such frameworks? I've looked around but I haven't found anything concrete.

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  • NHibernate Conventions

    - by Ricardo Peres
    Introduction It seems that nowadays everyone loves conventions! Not the ones that you go to, but the ones that you use, that is! It just happens that NHibernate also supports conventions, and we’ll see exactly how. Conventions in NHibernate are supported in two ways: Naming of tables and columns when not explicitly indicated in the mappings; Full domain mapping. Naming of Tables and Columns Since always NHibernate has supported the concept of a naming strategy. A naming strategy in NHibernate converts class and property names to table and column names and vice-versa, when a name is not explicitly supplied. In concrete, it must be a realization of the NHibernate.Cfg.INamingStrategy interface, of which NHibernate includes two implementations: DefaultNamingStrategy: the default implementation, where each column and table are mapped to identically named properties and classes, for example, “MyEntity” will translate to “MyEntity”; ImprovedNamingStrategy: underscores (_) are used to separate Pascal-cased fragments, for example, entity “MyEntity” will be mapped to a “my_entity” table. The naming strategy can be defined at configuration level (the Configuration instance) by calling the SetNamingStrategy method: 1: cfg.SetNamingStrategy(ImprovedNamingStrategy.Instance); Both the DefaultNamingStrategy and the ImprovedNamingStrategy classes offer singleton instances in the form of Instance static fields. DefaultNamingStrategy is the one NHibernate uses, if you don’t specify one. Domain Mapping In mapping by code, we have the choice of relying on conventions to do the mapping automatically. This means a class will inspect our classes and decide how they will relate to the database objects. The class that handles conventions is NHibernate.Mapping.ByCode.ConventionModelMapper, a specialization of the base by code mapper, NHibernate.Mapping.ByCode.ModelMapper. The ModelMapper relies on an internal SimpleModelInspector to help it decide what and how to map, but the mapper lets you override its decisions.  You apply code conventions like this: 1: //pick the types that you want to map 2: IEnumerable<Type> types = Assembly.GetExecutingAssembly().GetExportedTypes(); 3:  4: //conventions based mapper 5: ConventionModelMapper mapper = new ConventionModelMapper(); 6:  7: HbmMapping mapping = mapper.CompileMappingFor(types); 8:  9: //the one and only configuration instance 10: Configuration cfg = ...; 11: cfg.AddMapping(mapping); This is a very simple example, it lacks, at least, the id generation strategy, which you can add by adding an event handler like this: 1: mapper.BeforeMapClass += (IModelInspector modelInspector, Type type, IClassAttributesMapper classCustomizer) => 2: { 3: classCustomizer.Id(x => 4: { 5: //set the hilo generator 6: x.Generator(Generators.HighLow); 7: }); 8: }; The mapper will fire events like this whenever it needs to get information about what to do. And basically this is all it takes to automatically map your domain! It will correctly configure many-to-one and one-to-many relations, choosing bags or sets depending on your collections, will get the table and column names from the naming strategy we saw earlier and will apply the usual defaults to all properties, such as laziness and fetch mode. However, there is at least one thing missing: many-to-many relations. The conventional mapper doesn’t know how to find and configure them, which is a pity, but, alas, not difficult to overcome. To start, for my projects, I have this rule: each entity exposes a public property of type ISet<T> where T is, of course, the type of the other endpoint entity. Extensible as it is, NHibernate lets me implement this very easily: 1: mapper.IsOneToMany((MemberInfo member, Boolean isLikely) => 2: { 3: Type sourceType = member.DeclaringType; 4: Type destinationType = member.GetMemberFromDeclaringType().GetPropertyOrFieldType(); 5:  6: //check if the property is of a generic collection type 7: if ((destinationType.IsGenericCollection() == true) && (destinationType.GetGenericArguments().Length == 1)) 8: { 9: Type destinationEntityType = destinationType.GetGenericArguments().Single(); 10:  11: //check if the type of the generic collection property is an entity 12: if (mapper.ModelInspector.IsEntity(destinationEntityType) == true) 13: { 14: //check if there is an equivalent property on the target type that is also a generic collection and points to this entity 15: PropertyInfo collectionInDestinationType = destinationEntityType.GetProperties().Where(x => (x.PropertyType.IsGenericCollection() == true) && (x.PropertyType.GetGenericArguments().Length == 1) && (x.PropertyType.GetGenericArguments().Single() == sourceType)).SingleOrDefault(); 16:  17: if (collectionInDestinationType != null) 18: { 19: return (false); 20: } 21: } 22: } 23:  24: return (true); 25: }); 26:  27: mapper.IsManyToMany((MemberInfo member, Boolean isLikely) => 28: { 29: //a relation is many to many if it isn't one to many 30: Boolean isOneToMany = mapper.ModelInspector.IsOneToMany(member); 31: return (!isOneToMany); 32: }); 33:  34: mapper.BeforeMapManyToMany += (IModelInspector modelInspector, PropertyPath member, IManyToManyMapper collectionRelationManyToManyCustomizer) => 35: { 36: Type destinationEntityType = member.LocalMember.GetPropertyOrFieldType().GetGenericArguments().First(); 37: //set the mapping table column names from each source entity name plus the _Id sufix 38: collectionRelationManyToManyCustomizer.Column(destinationEntityType.Name + "_Id"); 39: }; 40:  41: mapper.BeforeMapSet += (IModelInspector modelInspector, PropertyPath member, ISetPropertiesMapper propertyCustomizer) => 42: { 43: if (modelInspector.IsManyToMany(member.LocalMember) == true) 44: { 45: propertyCustomizer.Key(x => x.Column(member.LocalMember.DeclaringType.Name + "_Id")); 46:  47: Type sourceType = member.LocalMember.DeclaringType; 48: Type destinationType = member.LocalMember.GetPropertyOrFieldType().GetGenericArguments().First(); 49: IEnumerable<String> names = new Type[] { sourceType, destinationType }.Select(x => x.Name).OrderBy(x => x); 50:  51: //set inverse on the relation of the alphabetically first entity name 52: propertyCustomizer.Inverse(sourceType.Name == names.First()); 53: //set mapping table name from the entity names in alphabetical order 54: propertyCustomizer.Table(String.Join("_", names)); 55: } 56: }; We have to understand how the conventions mapper thinks: For each collection of entities found, it will ask the mapper if it is a one-to-many; in our case, if the collection is a generic one that has an entity as its generic parameter, and the generic parameter type has a similar collection, then it is not a one-to-many; Next, the mapper will ask if the collection that it now knows is not a one-to-many is a many-to-many; Before a set is mapped, if it corresponds to a many-to-many, we set its mapping table. Now, this is tricky: because we have no way to maintain state, we sort the names of the two endpoint entities and we combine them with a “_”; for the first alphabetical entity, we set its relation to inverse – remember, on a many-to-many relation, only one endpoint must be marked as inverse; finally, we set the column name as the name of the entity with an “_Id” suffix; Before the many-to-many relation is processed, we set the column name as the name of the other endpoint entity with the “_Id” suffix, as we did for the set. And that’s it. With these rules, NHibernate will now happily find and configure many-to-many relations, as well as all the others. You can wrap this in a new conventions mapper class, so that it is more easily reusable: 1: public class ManyToManyConventionModelMapper : ConventionModelMapper 2: { 3: public ManyToManyConventionModelMapper() 4: { 5: base.IsOneToMany((MemberInfo member, Boolean isLikely) => 6: { 7: return (this.IsOneToMany(member, isLikely)); 8: }); 9:  10: base.IsManyToMany((MemberInfo member, Boolean isLikely) => 11: { 12: return (this.IsManyToMany(member, isLikely)); 13: }); 14:  15: base.BeforeMapManyToMany += this.BeforeMapManyToMany; 16: base.BeforeMapSet += this.BeforeMapSet; 17: } 18:  19: protected virtual Boolean IsManyToMany(MemberInfo member, Boolean isLikely) 20: { 21: //a relation is many to many if it isn't one to many 22: Boolean isOneToMany = this.ModelInspector.IsOneToMany(member); 23: return (!isOneToMany); 24: } 25:  26: protected virtual Boolean IsOneToMany(MemberInfo member, Boolean isLikely) 27: { 28: Type sourceType = member.DeclaringType; 29: Type destinationType = member.GetMemberFromDeclaringType().GetPropertyOrFieldType(); 30:  31: //check if the property is of a generic collection type 32: if ((destinationType.IsGenericCollection() == true) && (destinationType.GetGenericArguments().Length == 1)) 33: { 34: Type destinationEntityType = destinationType.GetGenericArguments().Single(); 35:  36: //check if the type of the generic collection property is an entity 37: if (this.ModelInspector.IsEntity(destinationEntityType) == true) 38: { 39: //check if there is an equivalent property on the target type that is also a generic collection and points to this entity 40: PropertyInfo collectionInDestinationType = destinationEntityType.GetProperties().Where(x => (x.PropertyType.IsGenericCollection() == true) && (x.PropertyType.GetGenericArguments().Length == 1) && (x.PropertyType.GetGenericArguments().Single() == sourceType)).SingleOrDefault(); 41:  42: if (collectionInDestinationType != null) 43: { 44: return (false); 45: } 46: } 47: } 48:  49: return (true); 50: } 51:  52: protected virtual new void BeforeMapManyToMany(IModelInspector modelInspector, PropertyPath member, IManyToManyMapper collectionRelationManyToManyCustomizer) 53: { 54: Type destinationEntityType = member.LocalMember.GetPropertyOrFieldType().GetGenericArguments().First(); 55: //set the mapping table column names from each source entity name plus the _Id sufix 56: collectionRelationManyToManyCustomizer.Column(destinationEntityType.Name + "_Id"); 57: } 58:  59: protected virtual new void BeforeMapSet(IModelInspector modelInspector, PropertyPath member, ISetPropertiesMapper propertyCustomizer) 60: { 61: if (modelInspector.IsManyToMany(member.LocalMember) == true) 62: { 63: propertyCustomizer.Key(x => x.Column(member.LocalMember.DeclaringType.Name + "_Id")); 64:  65: Type sourceType = member.LocalMember.DeclaringType; 66: Type destinationType = member.LocalMember.GetPropertyOrFieldType().GetGenericArguments().First(); 67: IEnumerable<String> names = new Type[] { sourceType, destinationType }.Select(x => x.Name).OrderBy(x => x); 68:  69: //set inverse on the relation of the alphabetically first entity name 70: propertyCustomizer.Inverse(sourceType.Name == names.First()); 71: //set mapping table name from the entity names in alphabetical order 72: propertyCustomizer.Table(String.Join("_", names)); 73: } 74: } 75: } Conclusion Of course, there is much more to mapping than this, I suggest you look at all the events and functions offered by the ModelMapper to see where you can hook for making it behave the way you want. If you need any help, just let me know!

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  • Stumbling Through: Visual Studio 2010 (Part III)

    The last post ended with us just getting started on stumbling into text template file customization, a task that required a Visual Studio extension (Tangible T4 Editor) to even have a chance at completing.  Despite the benefits of the Tangible T4 Editor, I still had a hard time putting together a solid text template that would be easy to explain.  This is mostly due to the way the files allow you to mix code (encapsulated in <# #>) with straight-up text to generate.  It is effective to be sure, but not very readable.  Nevertheless, I will try and explain what was accomplished in my custom tt file, though the details of which are not really the point of this article (my way of saying dont criticize my crappy code, and certainly dont use it in any somewhat real application.  You may become dumber just by looking at this code.  You have been warned really the footnote I should put at the end of all of my blog posts). To begin with, there were two basic requirements that I needed the code generator to satisfy:  Reading one to many entity framework files, and using the entities that were found to write one to many class files.  Thankfully, using the Entity Object Generator as a starting point gave us an example on how to do exactly that by using the MetadataLoader and EntityFrameworkTemplateFileManager you include references to these items and use them like so: // Instantiate an entity framework file reader and file writer MetadataLoader loader = new MetadataLoader(this); EntityFrameworkTemplateFileManager fileManager = EntityFrameworkTemplateFileManager.Create(this); // Load the entity model metadata workspace MetadataWorkspace metadataWorkspace = null; bool allMetadataLoaded =loader.TryLoadAllMetadata("MFL.tt", out metadataWorkspace); EdmItemCollection ItemCollection = (EdmItemCollection)metadataWorkspace.GetItemCollection(DataSpace.CSpace); // Create an IO class to contain the 'get' methods for all entities in the model fileManager.StartNewFile("MFL.IO.gen.cs"); Next, we want to be able to loop through all of the entities found in the model, and then each property for each entity so we can generate classes and methods for each.  The code for that is blissfully simple: // Iterate through each entity in the model foreach (EntityType entity in ItemCollection.GetItems<EntityType>().OrderBy(e => e.Name)) {     // Iterate through each primitive property of the entity     foreach (EdmProperty edmProperty in entity.Properties.Where(p => p.TypeUsage.EdmType is PrimitiveType && p.DeclaringType == entity))     {         // TODO:  Create properties     }     // Iterate through each relationship of the entity     foreach (NavigationProperty navProperty in entity.NavigationProperties.Where(np => np.DeclaringType == entity))     {         // TODO:  Create associations     } } There really isnt anything more advanced than that going on in the text template the only thing I had to blunder through was realizing that if you want the generator to interpret a line of code (such as our iterations above), you need to enclose the code in <# and #> while if you want the generator to interpret the VALUE of code, such as putting the entity name into the class name, you need to enclose the code in <#= and #> like so: public partial class <#=entity.Name#> To make a long story short, I did a lot of repetition of the above to come up with a text template that generates a class for each entity based on its properties, and a set of IO methods for each entity based on its relationships.  The two work together to provide lazy-loading for hierarchical data (such getting Team.Players) so it should be pretty intuitive to use on a front-end.  This text template is available here you can tweak the inputFiles array to load one or many different edmx models and generate the basic xml IO and class files, though it will probably only work correctly in the simplest of cases, like our MFL model described in the previous post.  Additionally, there is no validation, logging or error handling which is something I want to handle later by stumbling through the enterprise library 5.0. The code that gets generated isnt anything special, though using the LINQ to XML feature was something very new and exciting for me I had only worked with XML in the past using the DOM or XML Reader objects along with XPath, and the LINQ to XML model is just so much more elegant and supposedly efficient (something to test later).  For example, the following code was generated to create a Player object for each Player node in the XML:         return from element in GetXmlData(_PlayerDataFile).Descendants("Player")             select new Player             {                 Id = int.Parse(element.Attribute("Id").Value)                 ,ParentName = element.Parent.Name.LocalName                 ,ParentId = long.Parse(element.Parent.Attribute("Id").Value)                 ,Name = element.Attribute("Name").Value                 ,PositionId = int.Parse(element.Attribute("PositionId").Value)             }; It is all done in one line of code, no looping needed.  Even though GetXmlData loads the entire xml file just like the old XML DOM approach would have, it is supposed to be much less resource intensive.  I will definitely put that to the test after we develop a user interface for getting at this data.  Speaking of the data where IS the data?  Weve put together a pretty model and a bunch of code around it, but we dont have any data to speak of.  We can certainly drop to our favorite XML editor and crank out some data, but if it doesnt totally match our model, it will not load correctly.  To help with this, Ive built in a method to generate xml at any given layer in the hierarchy.  So for us to get the closest possible thing to real data, wed need to invoke MFL.IO.GenerateTeamXML and save the results to file.  Doing so should get us something that looks like this: <Team Id="0" Name="0">   <Player Id="0" Name="0" PositionId="0">     <Statistic Id="0" PassYards="0" RushYards="0" Year="0" />   </Player> </Team> Sadly, it is missing the Positions node (havent thought of a way to generate lookup xml yet) and the data itself isnt quite realistic (well, as realistic as MFL data can be anyway).  Lets manually remedy that for now to give us a decent starter set of data.  Note that this is TWO xml files Lookups.xml and Teams.xml: <Lookups Id=0>   <Position Id="0" Name="Quarterback"/>   <Position Id="1" Name="Runningback"/> </Lookups> <Teams Id=0>   <Team Id="0" Name="Chicago">     <Player Id="0" Name="QB Bears" PositionId="0">       <Statistic Id="0" PassYards="4000" RushYards="120" Year="2008" />       <Statistic Id="1" PassYards="4200" RushYards="180" Year="2009" />     </Player>     <Player Id="1" Name="RB Bears" PositionId="1">       <Statistic Id="2" PassYards="0" RushYards="800" Year="2007" />       <Statistic Id="3" PassYards="0" RushYards="1200" Year="2008" />       <Statistic Id="4" PassYards="3" RushYards="1450" Year="2009" />     </Player>   </Team> </Teams> Ok, so we have some data, we have a way to read/write that data and we have a friendly way of representing that data.  Now, what remains is the part that I have been looking forward to the most: present the data to the user and give them the ability to add/update/delete, and doing so in a way that is very intuitive (easy) from a development standpoint.Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Stumbling Through: Visual Studio 2010 (Part III)

    The last post ended with us just getting started on stumbling into text template file customization, a task that required a Visual Studio extension (Tangible T4 Editor) to even have a chance at completing.  Despite the benefits of the Tangible T4 Editor, I still had a hard time putting together a solid text template that would be easy to explain.  This is mostly due to the way the files allow you to mix code (encapsulated in <# #>) with straight-up text to generate.  It is effective to be sure, but not very readable.  Nevertheless, I will try and explain what was accomplished in my custom tt file, though the details of which are not really the point of this article (my way of saying dont criticize my crappy code, and certainly dont use it in any somewhat real application.  You may become dumber just by looking at this code.  You have been warned really the footnote I should put at the end of all of my blog posts). To begin with, there were two basic requirements that I needed the code generator to satisfy:  Reading one to many entity framework files, and using the entities that were found to write one to many class files.  Thankfully, using the Entity Object Generator as a starting point gave us an example on how to do exactly that by using the MetadataLoader and EntityFrameworkTemplateFileManager you include references to these items and use them like so: // Instantiate an entity framework file reader and file writer MetadataLoader loader = new MetadataLoader(this); EntityFrameworkTemplateFileManager fileManager = EntityFrameworkTemplateFileManager.Create(this); // Load the entity model metadata workspace MetadataWorkspace metadataWorkspace = null; bool allMetadataLoaded =loader.TryLoadAllMetadata("MFL.tt", out metadataWorkspace); EdmItemCollection ItemCollection = (EdmItemCollection)metadataWorkspace.GetItemCollection(DataSpace.CSpace); // Create an IO class to contain the 'get' methods for all entities in the model fileManager.StartNewFile("MFL.IO.gen.cs"); Next, we want to be able to loop through all of the entities found in the model, and then each property for each entity so we can generate classes and methods for each.  The code for that is blissfully simple: // Iterate through each entity in the model foreach (EntityType entity in ItemCollection.GetItems<EntityType>().OrderBy(e => e.Name)) {     // Iterate through each primitive property of the entity     foreach (EdmProperty edmProperty in entity.Properties.Where(p => p.TypeUsage.EdmType is PrimitiveType && p.DeclaringType == entity))     {         // TODO:  Create properties     }     // Iterate through each relationship of the entity     foreach (NavigationProperty navProperty in entity.NavigationProperties.Where(np => np.DeclaringType == entity))     {         // TODO:  Create associations     } } There really isnt anything more advanced than that going on in the text template the only thing I had to blunder through was realizing that if you want the generator to interpret a line of code (such as our iterations above), you need to enclose the code in <# and #> while if you want the generator to interpret the VALUE of code, such as putting the entity name into the class name, you need to enclose the code in <#= and #> like so: public partial class <#=entity.Name#> To make a long story short, I did a lot of repetition of the above to come up with a text template that generates a class for each entity based on its properties, and a set of IO methods for each entity based on its relationships.  The two work together to provide lazy-loading for hierarchical data (such getting Team.Players) so it should be pretty intuitive to use on a front-end.  This text template is available here you can tweak the inputFiles array to load one or many different edmx models and generate the basic xml IO and class files, though it will probably only work correctly in the simplest of cases, like our MFL model described in the previous post.  Additionally, there is no validation, logging or error handling which is something I want to handle later by stumbling through the enterprise library 5.0. The code that gets generated isnt anything special, though using the LINQ to XML feature was something very new and exciting for me I had only worked with XML in the past using the DOM or XML Reader objects along with XPath, and the LINQ to XML model is just so much more elegant and supposedly efficient (something to test later).  For example, the following code was generated to create a Player object for each Player node in the XML:         return from element in GetXmlData(_PlayerDataFile).Descendants("Player")             select new Player             {                 Id = int.Parse(element.Attribute("Id").Value)                 ,ParentName = element.Parent.Name.LocalName                 ,ParentId = long.Parse(element.Parent.Attribute("Id").Value)                 ,Name = element.Attribute("Name").Value                 ,PositionId = int.Parse(element.Attribute("PositionId").Value)             }; It is all done in one line of code, no looping needed.  Even though GetXmlData loads the entire xml file just like the old XML DOM approach would have, it is supposed to be much less resource intensive.  I will definitely put that to the test after we develop a user interface for getting at this data.  Speaking of the data where IS the data?  Weve put together a pretty model and a bunch of code around it, but we dont have any data to speak of.  We can certainly drop to our favorite XML editor and crank out some data, but if it doesnt totally match our model, it will not load correctly.  To help with this, Ive built in a method to generate xml at any given layer in the hierarchy.  So for us to get the closest possible thing to real data, wed need to invoke MFL.IO.GenerateTeamXML and save the results to file.  Doing so should get us something that looks like this: <Team Id="0" Name="0">   <Player Id="0" Name="0" PositionId="0">     <Statistic Id="0" PassYards="0" RushYards="0" Year="0" />   </Player> </Team> Sadly, it is missing the Positions node (havent thought of a way to generate lookup xml yet) and the data itself isnt quite realistic (well, as realistic as MFL data can be anyway).  Lets manually remedy that for now to give us a decent starter set of data.  Note that this is TWO xml files Lookups.xml and Teams.xml: <Lookups Id=0>   <Position Id="0" Name="Quarterback"/>   <Position Id="1" Name="Runningback"/> </Lookups> <Teams Id=0>   <Team Id="0" Name="Chicago">     <Player Id="0" Name="QB Bears" PositionId="0">       <Statistic Id="0" PassYards="4000" RushYards="120" Year="2008" />       <Statistic Id="1" PassYards="4200" RushYards="180" Year="2009" />     </Player>     <Player Id="1" Name="RB Bears" PositionId="1">       <Statistic Id="2" PassYards="0" RushYards="800" Year="2007" />       <Statistic Id="3" PassYards="0" RushYards="1200" Year="2008" />       <Statistic Id="4" PassYards="3" RushYards="1450" Year="2009" />     </Player>   </Team> </Teams> Ok, so we have some data, we have a way to read/write that data and we have a friendly way of representing that data.  Now, what remains is the part that I have been looking forward to the most: present the data to the user and give them the ability to add/update/delete, and doing so in a way that is very intuitive (easy) from a development standpoint.Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • What's a good entity hierarchy for a 2D game?

    - by futlib
    I'm in the process of building a new 2D game out of some code I wrote a while ago. The object hierarchy for entities is like this: Scene (e.g. MainMenu): Contains multiple entities and delegates update()/draw() to each Entity: Base class for all things in a scene (e.g. MenuItem or Alien) Sprite: Base class for all entities that just draw a texture, i.e. don't have their own drawing logic Does it make sense to split up entities and sprites up like that? I think in a 2D game, the terms entity and sprite are somewhat synonymous, right? But I do believe that I need some base class for entities that just draw a texture, as opposed to drawing themselves, to avoid duplication. Most entities are like that. One weird case is my Text class: It derives from Sprite, which accepts either the path of an image or an already loaded texture in its constructor. Text loads a texture in its constructor and passes that to Sprite. Can you outline a design that makes more sense? Or point me to a good object-oriented reference code base for a 2D game? I could only find 3D engine code bases of decent code quality, e.g. Doom 3 and HPL1Engine.

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  • Entity system in Lua, communication with C++ and level editor. Need advice.

    - by Notbad
    Hi!, I know this is a really difficult subject. I have been reading a lot this days about Entity systems, etc... And now I'm ready to ask some questions (if you don't mind answering them) because I'm really messed. First of all, I have a 2D basic editor written in Qt, and I'm in the process of adding entitiy edition. I want the editor to be able to receive RTTI information from entities to change properties, create some logic being able to link published events to published actions (Ex:A level activate event throws a door open action), etc... Because all of this I guess my entity system should be written in scripting, in my case Lua. In the other hand I want to use a component based design for my entities, and here starts my questions: 1) Should I define my componentes en C++? If I do this en C++ won't I loose all the RTTI information I want for my editor?. In the other hand, I use box2d for physics, if I define all my components in script won't it be a lot of work to expose third party libs to lua? 2) Where should I place the messa system for my game engine? Lua? C++?. I'm tempted to just have C++ object to behave as servers, offering services to lua business logic. Things like physics system, rendering system, input system, World class, etc... And for all the other things, lua. Creation/Composition of entities based on components, game logic, etc... Could anyone give any insight on how to accomplish this? And what aproach is better?. Thanks in advance, HexDump.

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  • Is the Entity Component System architecture object oriented by definition?

    - by tieTYT
    Is the Entity Component System architecture object oriented, by definition? It seems more procedural or functional to me. My opinion is that it doesn't prevent you from implementing it in an OO language, but it would not be idiomatic to do so in a staunchly OO way. It seems like ECS separates data (E & C) from behavior (S). As evidence: The idea is to have no game methods embedded in the entity. And: The component consists of a minimal set of data needed for a specific purpose Systems are single purpose functions that take a set of entities which have a specific component I think this is not object oriented because a big part of being object oriented is combining your data and behavior together. As evidence: In contrast, the object-oriented approach encourages the programmer to place data where it is not directly accessible by the rest of the program. Instead, the data is accessed by calling specially written functions, commonly called methods, which are bundled in with the data. ECS, on the other hand, seems to be all about separating your data from your behavior.

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  • Custom bean instantiation logic in Spring MVC

    - by Michal Bachman
    I have a Spring MVC application trying to use a rich domain model, with the following mapping in the Controller class: @RequestMapping(value = "/entity", method = RequestMethod.POST) public String create(@Valid Entity entity, BindingResult result, ModelMap modelMap) { if (entity== null) throw new IllegalArgumentException("An entity is required"); if (result.hasErrors()) { modelMap.addAttribute("entity", entity); return "entity/create"; } entity.persist(); return "redirect:/entity/" + entity.getId(); } Before this method gets executed, Spring uses BeanUtils to instantiate a new Entity and populate its fields. It uses this: ... ReflectionUtils.makeAccessible(ctor); return ctor.newInstance(args); Here's the problem: My entities are Spring managed beans. The reason for this is to inject DAOs on them. Instead of calling new, I use EntityFactory.createEntity(). When they're retrieved from the database, I have an interceptor that overrides the public Object instantiate(String entityName, EntityMode entityMode, Serializable id) method and hooks the factories into that. So the last piece of the puzzle missing here is how to force Spring to use the factory rather than its own BeanUtils reflective approach? Any suggestions for a clean solution? Thanks very much in advance.

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  • Why do I get Detached Entity exception when upgrading Spring Boot 1.1.4 to 1.1.5

    - by mmeany
    On updating Spring Boot from 1.1.4 to 1.1.5 a simple web application started generating detached entity exceptions. Specifically, a post authentication inteceptor that bumped number of visits was causing the problem. A quick check of loaded dependencies showed that Spring Data has been updated from 1.6.1 to 1.6.2 and a further check of the change log shows a couple of issues relating to optimistic locking, version fields and JPA issues that have been fixed. Well I am using a version field and it starts out as Null following recommendation to not set in the specification. I have produced a very simple test scenario where I get detached entity exceptions if the version field starts as null or zero. If I create an entity with version 1 however then I do not get these exceptions. Is this expected behaviour or is there still something amiss? Below is the test scenario I have for this condition. In the scenario the service layer that has been annotated @Transactional. Each test case makes multiple calls to the service layer - the tests are working with detached entities as this is the scenario I am working with in the full blown application. The test case comprises four tests: Test 1 - versionNullCausesAnExceptionOnUpdate() In this test the version field in the detached object is Null. This is how I would usually create the object prior to passing to the service. This test fails with a Detached Entity exception. I would have expected this test to pass. If there is a flaw in the test then the rest of the scenario is probably moot. Test 2 - versionZeroCausesExceptionOnUpdate() In this test I have set the version to value Long(0L). This is an edge case test and included because I found reference to Zero values being used for version field in the Spring Data change log. This test fails with a Detached Entity exception. Of interest simply because the following two tests pass leaving this as an anomaly. Test 3 - versionOneDoesNotCausesExceptionOnUpdate() In this test the version field is set to value Long(1L). Not something I would usually do, but considering the notes in the Spring Data change log I decided to give it a go. This test passes. Would not usually set the version field, but this looks like a work-around until I figure out why the first test is failing. Test 4 - versionOneDoesNotCausesExceptionWithMultipleUpdates() Encouraged by the result of test 3 I pushed the scenario a step further and perform multiple updates on the entity that started life with a version of Long(1L). This test passes. Reinforcement that this may be a useable work-around. The entity: package com.mvmlabs.domain; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.Table; import javax.persistence.Version; @Entity @Table(name="user_details") public class User { @Id @GeneratedValue(strategy=GenerationType.AUTO) private Long id; @Version private Long version; @Column(nullable = false, unique = true) private String username; @Column(nullable = false) private Integer numberOfVisits; public Long getId() { return id; } public void setId(Long id) { this.id = id; } public Long getVersion() { return version; } public void setVersion(Long version) { this.version = version; } public Integer getNumberOfVisits() { return numberOfVisits == null ? 0 : numberOfVisits; } public void setNumberOfVisits(Integer numberOfVisits) { this.numberOfVisits = numberOfVisits; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } } The repository: package com.mvmlabs.dao; import org.springframework.data.repository.CrudRepository; import com.mvmlabs.domain.User; public interface UserDao extends CrudRepository<User, Long>{ } The service interface: package com.mvmlabs.service; import com.mvmlabs.domain.User; public interface UserService { User save(User user); User loadUser(Long id); User registerVisit(User user); } The service implementation: package com.mvmlabs.service; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import org.springframework.transaction.annotation.Propagation; import org.springframework.transaction.annotation.Transactional; import org.springframework.transaction.support.TransactionSynchronizationManager; import com.mvmlabs.dao.UserDao; import com.mvmlabs.domain.User; @Service @Transactional(propagation=Propagation.REQUIRED, readOnly=false) public class UserServiceJpaImpl implements UserService { @Autowired private UserDao userDao; @Transactional(readOnly=true) @Override public User loadUser(Long id) { return userDao.findOne(id); } @Override public User registerVisit(User user) { user.setNumberOfVisits(user.getNumberOfVisits() + 1); return userDao.save(user); } @Override public User save(User user) { return userDao.save(user); } } The application class: package com.mvmlabs; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.EnableAutoConfiguration; import org.springframework.context.annotation.ComponentScan; import org.springframework.context.annotation.Configuration; @Configuration @ComponentScan @EnableAutoConfiguration public class Application { public static void main(String[] args) { SpringApplication.run(Application.class, args); } } The POM: <?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.mvmlabs</groupId> <artifactId>jpa-issue</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>spring-boot-jpa-issue</name> <description>JPA Issue between spring boot 1.1.4 and 1.1.5</description> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.1.5.RELEASE</version> <relativePath /> <!-- lookup parent from repository --> </parent> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jpa</artifactId> </dependency> <dependency> <groupId>org.hsqldb</groupId> <artifactId>hsqldb</artifactId> <scope>runtime</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> </dependencies> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <start-class>com.mvmlabs.Application</start-class> <java.version>1.7</java.version> </properties> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project> The application properties: spring.jpa.hibernate.ddl-auto: create spring.jpa.hibernate.naming_strategy: org.hibernate.cfg.ImprovedNamingStrategy spring.jpa.database: HSQL spring.jpa.show-sql: true spring.datasource.url=jdbc:hsqldb:file:./target/testdb spring.datasource.username=sa spring.datasource.password= spring.datasource.driverClassName=org.hsqldb.jdbcDriver The test case: package com.mvmlabs; import org.junit.Assert; import org.junit.Test; import org.junit.runner.RunWith; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.test.SpringApplicationConfiguration; import org.springframework.test.context.junit4.SpringJUnit4ClassRunner; import com.mvmlabs.domain.User; import com.mvmlabs.service.UserService; @RunWith(SpringJUnit4ClassRunner.class) @SpringApplicationConfiguration(classes = Application.class) public class ApplicationTests { @Autowired UserService userService; @Test public void versionNullCausesAnExceptionOnUpdate() throws Exception { User user = new User(); user.setUsername("Version Null"); user.setNumberOfVisits(0); user.setVersion(null); user = userService.save(user); user = userService.registerVisit(user); Assert.assertEquals(new Integer(1), user.getNumberOfVisits()); Assert.assertEquals(new Long(1L), user.getVersion()); } @Test public void versionZeroCausesExceptionOnUpdate() throws Exception { User user = new User(); user.setUsername("Version Zero"); user.setNumberOfVisits(0); user.setVersion(0L); user = userService.save(user); user = userService.registerVisit(user); Assert.assertEquals(new Integer(1), user.getNumberOfVisits()); Assert.assertEquals(new Long(1L), user.getVersion()); } @Test public void versionOneDoesNotCausesExceptionOnUpdate() throws Exception { User user = new User(); user.setUsername("Version One"); user.setNumberOfVisits(0); user.setVersion(1L); user = userService.save(user); user = userService.registerVisit(user); Assert.assertEquals(new Integer(1), user.getNumberOfVisits()); Assert.assertEquals(new Long(2L), user.getVersion()); } @Test public void versionOneDoesNotCausesExceptionWithMultipleUpdates() throws Exception { User user = new User(); user.setUsername("Version One Multiple"); user.setNumberOfVisits(0); user.setVersion(1L); user = userService.save(user); user = userService.registerVisit(user); user = userService.registerVisit(user); user = userService.registerVisit(user); Assert.assertEquals(new Integer(3), user.getNumberOfVisits()); Assert.assertEquals(new Long(4L), user.getVersion()); } } The first two tests fail with detached entity exception. The last two tests pass as expected. Now change Spring Boot version to 1.1.4 and rerun, all tests pass. Are my expectations wrong? Edit: This code saved to GitHub at https://github.com/mmeany/spring-boot-detached-entity-issue

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  • IPMI sdr entity 8 (memory module) only showing 3 records?

    - by thinice
    I've got two Dell PE R710's - A has a single socket and 3 DIMMs in one bank B has both sockets and 6 (2 banks @ 3 DIMMs) filled The output from "ipmitool sdr entity 8" confuses me - according to the OpenIPMI documentation these are supposed to represent DIMM slots. Output from A (1 CPU, 3 DIMMS, 1 bank.): ~#: ipmitool sdr entity 8 Temp | 0Ah | ok | 8.1 | 27 degrees C Temp | 0Bh | ns | 8.1 | Disabled Temp | 0Ch | ucr | 8.1 | 52 degrees C Output from B (2 CPUs, 3 DIMMS in both banks, 6 total): ~#: ipmitool sdr entity 8 Temp | 0Ah | ok | 8.1 | 26 degrees C Temp | 0Bh | ok | 8.1 | 25 degrees C Temp | 0Ch | ucr | 8.1 | 51 degrees C Now, I'm starting to think this output isn't DIMMS themselves, but maybe a sensor for each bank and something else? (Otherwise, shouldn't I see 6 readings for the one with both banks active?) The CPU's aren't near 50 deg C, so I doubt the significantly higher reading is due to proximity - Is anyone able to explain what I'm seeing? Does the output from my ipmitool sdr entity 8 -v here on pastebin seem to hint at different sensors? The sensor naming conventions are poor - seems like a dell thing. Here is output from racadm racdump

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  • Add SQL Azure database to Azure Web Role and persist data with entity framework code first.

    - by MagnusKarlsson
    In my last post I went for a warts n all approach to set up a web role on Azure. In this post I’ll describe how to add an SQL Azure database to the project. This will be described with an as minimal as possible amount of code and screen dumps. All questions are welcome in the comments area. Please don’t email since questions answered in the comments field is made available to other visitors. As an example we will add a comments section to the site we used in the previous post (Länk här). Steps: 1. Create a Comments entity and then use Scaffolding to set up controller and view, and add ConnectionString to web.config. 2. Create SQL Azure database in Management Portal and link the new database 3. Test it online!   1. Right click Models folder, choose add, choose “class…” . Name the Class Comment. 1.1 Replace the Code in the class with the following: using System.Data.Entity; namespace MvcWebRole1.Models { public class Comment {    public int CommentId { get; set; }    public string Name { get; set; }      public string Content { get; set; } } public class CommentsDb : DbContext { public DbSet<Comment> CommentEntries { get; set; } } } Now Entity Framework can create a database and a table named Comment. Build your project to assert there are no build errors.   1.2 Right click Controllers folder, choose add, choose “class…” . Name the Class CommentController and fill out the values as in the example below.     1.3 Click Add. Visual Studio now creates default View for CRUD operations and a Controller adhering to these and opens them. 1.3 Open Web.config and add the following connectionstring in <connectionStrings> node. <add name="CommentsDb” connectionString="data source=(LocalDB)\v11.0;Integrated Security=SSPI;AttachDbFileName=|DataDirectory|\CommentsDb.mdf;Initial Catalog=CommentsDb;MultipleActiveResultSets=True" providerName="System.Data.SqlClient" />   1.4 Save All and press F5 to start the application. 1.5 Go to http://127.0.0.1:81/Comments which will redirect you through CommentsController to the Index View which looks like this:     Click Create new. In the Create-view, add name and content and press Create.   1: // 2: // POST: /Comments/Create 3:  4: [HttpPost] 5: public ActionResult Create(Comment comment) 6: { 7: if (ModelState.IsValid) 8: { 9: db.CommentEntries.Add(comment); 10: db.SaveChanges(); 11: return RedirectToAction("Index"); 12: } 13:  14: return View(comment); 15: } 16:    The default View() is Index so that is the View you will come to. Looking like this: 1: // 2: // GET: /Comments/ 3: 4: public ActionResult Index() 5: { 6: return View(db.CommentEntries.ToList()); 7: } Resulting in the following screen dump(success!):   2. Now, go to the Management portal and Create a new db.   2.1 With the new database created. Click the DB icon in the left most menu. Then click the newly created database. Click DASHBOARD in the top menu. Finally click Connections strings in the right menu to get the connection string we need to add in our web.debug.config file.   2.2 Now, take a copy of the connection String earlier added to the web.config and paste in web.debug.conifg in the connectionstrings node. Replace everything within “ “ in the copied connectionstring with that you got from SQL Azure. You will have something like this:   2.3 Rebuild the application, right click the cloud project and choose “Package…” (if you haven’t set up publishing profile which we will do in our next blog post). Remember to choose the right config file, use debug for staging and release for production so your databases won’t collide. You should see something like this:   2.4 Go to Management Portal and click the Web Services menu, choose your service and click update in the bottom menu.   2.5 Link the newly created database to your application. Click the LINKED RESOURCES in the top menu and then click “Link” in the bottom menu. You should get something like this. 3. Alright then. Under the Dashboard you can find the link to your application. Click it to open it in a browser and then go to ~/Comments to try it out just the way we did locally. Success and end of this story!

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  • DDD and Value Objects. Are mutable Value Objects a good candidate for Non Aggr. Root Entity?

    - by Tony
    Here is a little problem Have an entity, with a value object. Not a problem. I replace a value object for a new one, then nhibernate inserts the new value and orphan the old one, then deletes it. Ok, that's a problem. Insured is my entity in my domain. He has a collection of Addresses (value objects). One of the addresses is the MailingAddress. When we want to update the mailing address, let's say zipcode was wrong, following Mr. Evans doctrine, we must replace the old object for a new one since it's immutable (a value object right?). But we don't want to delete the row thou, because that address's PK is a FK in a MailingHistory table. So, following Mr. Evans doctrine, we are pretty much screwed here. Unless i make my addressses Entities, so i don't have to "replace" it, and simply update its zipcode member, like the old good days. What would you suggest me in this case? The way i see it, ValueObjects are only useful when you want to encapsulate a group of database table's columns (component in nhibernate). Everything that has a persistence id in the database, is better off to make it an Entity (not necessarily an aggregate root) so you can update its members without recreating the whole object graph, specially if that's a deep-nested object. Do you concur? Is it allowed by Mr. Evans to have a mutable value object? Or is a mutable value object a candidate for an Entity? Thanks

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