NameValueListBase using Guid and String instead of Int and String

ktran posted on Wednesday, May 07, 2008

I'm using the CSLA.NET 3.5.1 version.  I tried changing the RoleList class from Project Tracker to point to my database roles table which uses a Guid for the RoleId instead of integer.  When I use the following code in my class  I get a InvalidCastException

Unable to cast object of type 'System.Collections.Generic.List`1[Csla.NameValueListBase`2+NameValuePair[System.Int32,System.String]]' to type 'System.Collections.Generic.IList`1[Csla.NameValueListBase`2+NameValuePair[System.Guid,System.String]]'.

using Csla;
using Csla.Data;
using System;
using System.Linq;

namespace ProjectTracker.Library
{
    [Serializable()]
    public class RoleList : NameValueListBase<Guid, string>
    {
        #region  Business Methods

        public static Guid DefaultRole()
        {
            RoleList list = GetList();
            if (list.Count > 0)
                return list.Items[0].Key;
            else
                throw new NullReferenceException("No roles available; default role can not be returned");
        }

        #endregion

        #region  Factory Methods

        private static RoleList _list;

        public static RoleList GetList()
        {
            if (_list == null)
                _list = DataPortal.Fetch<RoleList>();
            return _list;
        }

        /// <summary>
        /// Clears the in-memory RoleList cache
        /// so the list of roles is reloaded on
        /// next request.
        /// </summary>
        public static void InvalidateCache()
        {
            _list = null;
        }

        private RoleList()
        { /* require use of factory methods */ }

        #endregion

        #region  Data Access

        private void DataPortal_Fetch()
        {
            this.RaiseListChangedEvents = false;
            using (var ctx = ContextManager<ProjectTracker.DalLinq.AspNetDbDataContext>.GetManager(ProjectTracker.DalLinq.Database.AspNetDb))
            {
                var data = from role in ctx.DataContext.aspnet_Roles
                           select new NameValuePair(role.RoleId, role.RoleName);
                IsReadOnly = false;
                this.AddRange(data);
                IsReadOnly = true;
            }
            this.RaiseListChangedEvents = true;
        }

        #endregion

    }
}

Any help on this matter would be greatly appreciated.

Thanks,

Kent

RockfordLhotka replied on Wednesday, May 07, 2008

ktran:

Unable to cast object of type 'System.Collections.Generic.List`1[Csla.NameValueListBase`2+NameValuePair[System.Int32,System.String]]' to type 'System.Collections.Generic.IList`1[Csla.NameValueListBase`2+NameValuePair[System.Guid,System.String]]'.

Somewhere in your code you still have a field or class declared as NameValueListBase<int,string> - the exeption is quite clear on that

In fact, it appears that your actual type must be declared as an <int, string> and your field is of <guid, string> - and of course you can't cast the former to the latter.

ktran replied on Thursday, May 08, 2008

Thanks for you reply Rocky.  To clarify are you saying that the NameValueListBase has to be a

<int, string> pair or can you use it for <guid, string> or whatever combonation of data types?  Because there is nowhere in my new project that declares NameValueListBase<int,string>.  I've checked the Dbml File for my Linq to Sql classes and the fields I'm using are the expected data types <guid, string>

kent

RockfordLhotka replied on Thursday, May 08, 2008

ktran replied on Friday, May 09, 2008

Thanks Rocky, I got it worked out, stupid mistake I overlooked.

I really appreciate your prompt replies :)

Kent