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POLINQ to SQL INSERT Failing
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  1. POLINQ to SQL INSERT Failing
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    copied!<p>I am experiencing a very frustrating issue when trying to insert a new record using LINQ to SQL. If I step through this code sometimes it inserts the new record but most of the time it doesn't. When it fails I seeing the following error.</p> <blockquote> <p>Cannot insert the value NULL into column 'Name', table 'EquipmentManufacturer'; column does not allow nulls. INSERT fails. The statement has been terminated.</p> </blockquote> <p>This error is complaining about the 'Name' field being null but that should not be the case. When I debug and step through this collection["Name"] has the value I entered on the form.</p> <p>Here is the table create statement.</p> <pre><code>CREATE TABLE [EquipmentManufacturer] ( [EquipmentManufacturerID] [int] IDENTITY(1,1) NOT NULL, [Name] [nvarchar](50) NOT NULL, CONSTRAINT [PK_EquipmentManufacturer] PRIMARY KEY CLUSTERED ( [EquipmentManufacturerID] ASC ) ON [PRIMARY] ) ON [PRIMARY] </code></pre> <p>Here is the ASP.NET MVC Controller and Create Action where I am trying to add a new record.</p> <pre><code>public partial class EquipmentManufacturerController : Controller { private IRepository&lt;EquipmentManufacturer&gt; reposManu; // POST: /EquipmentManufacturer/Create [AcceptVerbs(HttpVerbs.Post)] public virtual ActionResult Create(FormCollection collection) { EquipmentManufacturer entity = reposManu.New(); try { //HACK: Something screwy is going on here the entity oject doesn't always get updated correctly //UpdateModel(entity); entity.Name = collection["Name"]; reposManu.Insert(entity); reposManu.SubmitChanges(); return RedirectToAction("Details", new { id = entity.EquipmentManufacturerID }); } catch (RulesException ex) { ex.AddModelStateErrors(ModelState, "EquipmentManufacturer"); return ModelState.IsValid ? RedirectToAction("Create") : (ActionResult)View(); } } } </code></pre> <p>Here is the Create.aspx view.</p> <pre><code>&lt;asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server"&gt; &lt;h2&gt;Create&lt;/h2&gt; &lt;%= Html.ValidationSummary("Create was unsuccessful. Please correct the errors and try again.") %&gt; &lt;% using (Html.BeginForm()) {%&gt; &lt;fieldset&gt; &lt;legend&gt;Fields&lt;/legend&gt; &lt;p&gt; &lt;label for="Name"&gt;Name:&lt;/label&gt; &lt;%= Html.TextBox("Name") %&gt; &lt;%= Html.ValidationMessage("Name") %&gt; &lt;/p&gt; &lt;p&gt; &lt;input type="submit" value="Create" /&gt; &lt;/p&gt; &lt;/fieldset&gt; &lt;% } %&gt; &lt;%= Html.ClientSideValidation&lt;EquipmentManufacturer&gt;() %&gt; &lt;div&gt; &lt;%=Html.ActionLink("Back to List", "Index") %&gt; &lt;/div&gt; &lt;/asp:Content&gt; </code></pre> <p>Here is the Repository implementation I am using.</p> <pre><code>public class Repository&lt;T&gt; : IRepository&lt;T&gt; where T : class { public IDataContext DC { get; set; } public Repository(IDataContext dataContext) { DC = dataContext; } /// &lt;summary&gt; /// Return all instances of type T. /// &lt;/summary&gt; /// &lt;returns&gt;&lt;/returns&gt; public IEnumerable&lt;T&gt; All() { return GetTable; } /// &lt;summary&gt; /// Return all instances of type T that match the expression exp. /// &lt;/summary&gt; /// &lt;param name="exp"&gt;&lt;/param&gt; /// &lt;returns&gt;&lt;/returns&gt; public IQueryable&lt;T&gt; Find(Expression&lt;Func&lt;T, bool&gt;&gt; exp) { return GetTable.Where&lt;T&gt;(exp); } /// &lt;summary&gt;See IRepository&lt;/summary&gt; /// &lt;param name="exp"&gt;&lt;/param&gt; /// &lt;returns&gt;&lt;/returns&gt; public T Single(Expression&lt;Func&lt;T, bool&gt;&gt; exp) { return GetTable.SingleOrDefault(exp); } /// &lt;summary&gt;See IRepository&lt;/summary&gt; /// &lt;param name="exp"&gt;&lt;/param&gt; /// &lt;returns&gt;&lt;/returns&gt; public T First(Expression&lt;Func&lt;T, bool&gt;&gt; exp) { return GetTable.First(exp); } /// &lt;summary&gt;See IRepository&lt;/summary&gt; /// &lt;param name="entity"&gt;&lt;/param&gt; public virtual void Delete(T entity) { DC.Context.GetTable&lt;T&gt;().DeleteOnSubmit(entity); } /// &lt;summary&gt; /// Create a new instance of type T. /// &lt;/summary&gt; /// &lt;returns&gt;&lt;/returns&gt; public virtual T New() { T entity = Activator.CreateInstance&lt;T&gt;(); GetTable.InsertOnSubmit(entity); return entity; } /// &lt;summary&gt; /// Adds an insance T. /// &lt;/summary&gt; /// &lt;returns&gt;&lt;/returns&gt; public virtual void Insert(T entity) { GetTable.InsertOnSubmit(entity); } /// &lt;summary&gt; /// Update entity. /// &lt;/summary&gt; /// &lt;returns&gt;&lt;/returns&gt; public virtual void Update(T entity) { DC.Context.Refresh(System.Data.Linq.RefreshMode.KeepCurrentValues, entity); } /// &lt;summary&gt;See IRepository&lt;/summary&gt; public void SubmitChanges() { DC.SubmitChanges(); } private string PrimaryKeyName { get { return TableMetadata.RowType.IdentityMembers[0].Name; } } private System.Data.Linq.Table&lt;T&gt; GetTable { get { return DC.Context.GetTable&lt;T&gt;(); } } private System.Data.Linq.Mapping.MetaTable TableMetadata { get { return DC.Context.Mapping.GetTable(typeof(T)); } } private System.Data.Linq.Mapping.MetaType ClassMetadata { get { return DC.Context.Mapping.GetMetaType(typeof(T)); } } } </code></pre>
 

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