Unable to materialize field [LockVersion]

Hi,

I get the following exception:

Unable to materialize field [LockVersion] on type [mcSphere.WebServer.DataServices.Domain.Model.Developer]: field is type 'System.Int32' but database returned type 'System.DBNull'. Check your table has an Id column and that your mappings are correct. See inner exception for details.

I have got two tables connected via a one-to-many association.

I set for some fields an aggregate name, the one-to-many association is lazy loaded.

The LockVersion is not null at the DB.

I get this SQL logged out:

SELECT
  Developer.*
FROM
  (
    SELECT
      Developer.Id AS [Developer.Id],
      Developer.AuditChangedAt AS [Developer.AuditChangedAt],
      Developer.AuditCreatedAt AS [Developer.AuditCreatedAt],
      Developer.CompanyWebSideUrl AS [Developer.CompanyWebSideUrl],
      Developer.DotNetNukeUserId AS [Developer.DotNetNukeUserId],
      Developer.IsApproved AS [Developer.IsApproved],
      Developer.LockVersion AS [Developer.LockVersion],
      Developer.Name AS [Developer.Name],
      ROW_NUMBER() OVER(ORDER BY Developer.Name) as RowNumber
    FROM
      Developer
    WHERE
      Developer.Name LIKE 'f%' ESCAPE '\'
  )
  Developer
WHERE
  RowNumber > 0 AND
  RowNumber <= 10

If I select the entity without using "WithAggregate" the error disapears. Fur sure I get one select for each access to a lazy loaded field (the one with the aggregate name specified)

If i execute the sql at the SSMS, the Developer.LockVersion is "0".

Any Ideas?

Could you post your Developer class code please?  Thanks!

  [Serializable]
  [System.CodeDom.Compiler.GeneratedCode("LightSpeedModelGenerator", "1.0.0.0")]
  [System.ComponentModel.DataObject]
  public partial class Developer : Entity<int>
  {
    #region Fields
 
    [ValidateLength(0, 100)]
    [EagerLoad(AggregateName="EditDeveloper")]
    [EagerLoad(AggregateName="ViewDeveloperInfo")]
    private string _name;
    [ValidateLength(0, 50)]
    [ValidateUri]
    [EagerLoad(AggregateName="EditDeveloper")]
    [EagerLoad(AggregateName="ViewDeveloperInfo")]
    private string _companyWebSideUrl;
    [ValidateLength(0, 100)]
    [ValidateEmailAddress]
    [EagerLoad(AggregateName="EditDeveloper")]
    private string _eMailAddress;
    [EagerLoad(AggregateName="EditDeveloper")]
    [EagerLoad(AggregateName="ViewDeveloperInfo")]
    private bool _isApproved;
    [EagerLoad(AggregateName="EditDeveloper")]
    [EagerLoad(AggregateName="ViewDeveloperInfo")]
    private System.Nullable<int> _dotNetNukeUserId;

    #pragma warning disable 649  // "Field is never assigned to" - LightSpeed assigns these fields internally
    private readonly int _lockVersion;
    #pragma warning restore 649   
    [ValueObject]
    private Audit _audit;

    #endregion
   
    #region Field attribute and view names
   
    /// <summary>Identifies the Name entity attribute.</summary>
    public const string NameField = "Name";
    /// <summary>Identifies the CompanyWebSideUrl entity attribute.</summary>
    public const string CompanyWebSideUrlField = "CompanyWebSideUrl";
    /// <summary>Identifies the EMailAddress entity attribute.</summary>
    public const string EMailAddressField = "EMailAddress";
    /// <summary>Identifies the IsApproved entity attribute.</summary>
    public const string IsApprovedField = "IsApproved";
    /// <summary>Identifies the DotNetNukeUserId entity attribute.</summary>
    public const string DotNetNukeUserIdField = "DotNetNukeUserId";


    #endregion
   
    #region Relationships

    [EagerLoad]
    [ReverseAssociation("Developer")]
    private readonly EntityCollection<AddIn> _addIns = new EntityCollection<AddIn>();


    #endregion
   
    #region Properties

    public EntityCollection<AddIn> AddIns
    {
      get { return Get(_addIns); }
    }


    public string Name
    {
      get { return Get(ref _name, "Name"); }
      set { Set(ref _name, value, "Name"); }
    }

    public string CompanyWebSideUrl
    {
      get { return Get(ref _companyWebSideUrl, "CompanyWebSideUrl"); }
      set { Set(ref _companyWebSideUrl, value, "CompanyWebSideUrl"); }
    }

    public string EMailAddress
    {
      get { return Get(ref _eMailAddress, "EMailAddress"); }
      set { Set(ref _eMailAddress, value, "EMailAddress"); }
    }

    public bool IsApproved
    {
      get { return Get(ref _isApproved, "IsApproved"); }
      set { Set(ref _isApproved, value, "IsApproved"); }
    }

    public System.Nullable<int> DotNetNukeUserId
    {
      get { return Get(ref _dotNetNukeUserId, "DotNetNukeUserId"); }
      set { Set(ref _dotNetNukeUserId, value, "DotNetNukeUserId"); }
    }
    /// <summary>Gets the row version number for concurrency checking</summary>
    public int LockVersion
    {
      get { return _lockVersion; }
    }
    public Audit Audit
    {
      get { return Get(ref _audit); }
      set { Set(ref _audit, value, "Audit"); }
    }

    #endregion
  }

Hmm, I'm not able to reproduce this.

Is there a single or class table inheritance in play?  This kind of error can result from a known issue if you have sibling classes in the hierarchy containing fields with the same name.

Otherwise, could you provide us with a small buildable console or NUnit test project, and a sample database, that replicate the issue?  Thanks!

I send you a download link for the test project.

Thanks for the repro.  Although it is clearly an error that LightSpeed is trying to load a NULL LockVersion, and we will investigate further, the code you're using contains an uneasy mix of server-side and client-side processing, and by changing this you can easily work around the bug.

Specifically, this code:

  select
    new NameValue
      {
        Id = getTheId(d), 
        Name = getTheName(d)
      }

is using client-side Funcs rather than expressions.  Change it to:

  select
    new NameValue
      {
        Id = d.Id,
        Name = d.Name
      }

and the problem goes away (and the projection will be carried out on the server).

Alternatively, if you need to be able to use client-side Funcs, throw in an AsEnumerable():

  var tempList = (from
                    d in developers.AsEnumerable()
                  select
                    new NameValue
                      {
                        Id = getTheId(d), 
                        Name = getTheName(d)
                      }
                  )
                  .ToList();

This will be no less efficient than your current code because your select is already running client-side (and developers already has the paging bits in it).

Thanks for having a look at it.

The repo is a "striped down to the problem" version of my original code. In my orignal code I pass the IQueryable<T>, getTheId and getTheName to a function which fills up a autocompletion combobox within a web service. It looks something like that one:

public void AddItems<TEntity>(RadComboBoxData comboBoxData, IQueryable<TEntity> items, Func<TEntity, string> getTextFunc, Func<TEntity, string> getIdFunc, ...)

{

      IList<RadComboBoxItemData> toAddItems = (from
                                                 item in items
                                               select
                                                 new RadComboBoxItemData { Text = getTextFunc(item), Value = getIdFunc(item) }

                                              )
                                              .ToList();
...

}

where the calling code looks something like this:

        using (IUseCaseController<EntitiesUnitOfWork> controller = CreateNewUseCaseController())
        {
          var spec = DeveloperFactory.CreateSpecForAutoCompletionByNameService(searchTerm)
                                     .WithPagingOf(context.NumberOfItems, ItemsPerRequest);

          AddItems(result,
                   controller.SelectStatisfying(spec),
                   dev => formatDisplayText(dev, textFormat),
                   dev => dev.Id,

                   ...
                  );
        }

So I changed the function to:

public void AddItems<TEntity>(RadComboBoxData comboBoxData,IEnumerable <TEntity> items, Func<TEntity, string> getTextFunc, Func<TEntity, string> getIdFunc, ...)

and the call to:

using (IUseCaseController<EntitiesUnitOfWork> controller = CreateNewUseCaseController())
        {
          var spec = DeveloperFactory.CreateSpecForAutoCompletionByNameService(searchTerm)
                                     .WithPagingOf(context.NumberOfItems, ItemsPerRequest);

          AddItems(result,
                   controller.SelectStatisfying(spec).AsEnumerable(),
                   dev => formatDisplayText(dev, textFormat),
                   dev => dev.Id,                  

                   ...
                  );
        }

And it is working.

Thanks again!
- Sörnt