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NHibernate KeyNotFoundException

My ASP.NET application runs fine in local instance of VS 2012 but not in VS 2015. It is throwing
Systems.Collections.Generic.KeyNotFoundException occurred in mscorlib.dll but not handled in user code
The application also runs fine when deployed on the server but issue occurs only in local machine - NHibernate session key being null and breaks on the following line.
var sessionInitializer = map[sessionFactory]
My code is pasted below and I am following similar implementation as in the following link (I have everything up until the IWindsorInstaller section from the link) -
http://nhibernate.info/blog/2011/03/02/effective-nhibernate-session-management-for-web-apps.html
public class LazyNHWebSessionContext : ICurrentSessionContext
{
private readonly ISessionFactoryImplementor factory;
private const string CurrentSessionContextKey =
"NHibernateCurrentSession";
public LazyNHWebSessionContext(ISessionFactoryImplementor factory)
{
this.factory = factory;
}
/// <summary>
/// Retrieve the current session for the session factory.
/// </summary>
/// <returns></returns>
public ISession CurrentSession()
{
Lazy<ISession> initializer;
var currentSessionFactoryMap = GetCurrentFactoryMap();
if (currentSessionFactoryMap == null ||
!currentSessionFactoryMap.TryGetValue(factory, out initializer))
{
return null;
}
return initializer.Value;
}
/// <summary>
/// Bind a new sessionInitializer to the context of the sessionFactory.
/// </summary>
/// <param name="sessionInitializer"></param>
/// <param name="sessionFactory"></param>
public static void Bind(Lazy<ISession> sessionInitializer, ISessionFactory sessionFactory)
{
var map = GetCurrentFactoryMap();
map[sessionFactory] = sessionInitializer;
}
/// <summary>
/// Unbind the current session of the session factory.
/// </summary>
/// <param name="sessionFactory"></param>
/// <returns></returns>
public static ISession UnBind(ISessionFactory sessionFactory)
{
var map = GetCurrentFactoryMap();
var sessionInitializer = map[sessionFactory];
map[sessionFactory] = null;
if (sessionInitializer == null || !sessionInitializer.IsValueCreated) return null;
return sessionInitializer.Value;
}
/// <summary>
/// Provides the CurrentMap of SessionFactories.
/// If there is no map create/store and return a new one.
/// </summary>
/// <returns></returns>
private static IDictionary<ISessionFactory, Lazy<ISession>> GetCurrentFactoryMap()
{
//var contextItem = HttpContext.Current.Items[CurrentSessionContextKey];
if (HttpContext.Current == null) return null;
var currentFactoryMap = (IDictionary<ISessionFactory, Lazy<ISession>>)
HttpContext.Current.Items[CurrentSessionContextKey];
if (currentFactoryMap == null)
{
currentFactoryMap = new Dictionary<ISessionFactory, Lazy<ISession>>();
HttpContext.Current.Items[CurrentSessionContextKey] = currentFactoryMap;
}
return currentFactoryMap;
}
}

Postsharp MethodInterceptionAspect attribute throws EntrypointNotFoundException

I have recently updated PostSharp to v4.1.13 and I have started receiving this error when I try to build my solution:
The custom attribute 'True.Kentico.Caching.KenticoCacheAttribute' constructor threw the exception EntryPointNotFoundException: Entry point was not found.
This attribute implements caching, and has worked before, so I'm wondering what would be the cause of it breaking. I am using this attribute in other assemblies referencing the aspect's containing assembly, and I get that error in there as well.
The following is the code for the attribute. Apologies, it contains a number of constructors.
[Serializable]
public class KenticoCacheAttribute : MethodInterceptionAspect
{
public int CacheMinutes { get; set; }
/// <summary>
/// the string value of the cache dependency key. If it uses parameters from the method, include a {0} to format with the method parameter
/// </summary>
public string CacheDependency { get; set; }
public string[] CacheDependencyStrings { get; set; }
public KenticoCacheDependencyObtainFrom ObtainCacheDependencyFrom { get; set; }
/// <summary>
/// whether caching is enabled - default from app settings
/// </summary>
public bool CacheEnabled { get; set; }
/// <summary>
/// this is the index of the parameter that will be used to format the cachedependency, if required
/// </summary>
public int CacheDependencyParameterIndex { get; set; }
public string CacheDependencyObjectProperty { get; set; }
private string _methodName;
/// <summary>
/// initializes the cache attribute to use a static dependency
/// </summary>
/// <param name="cacheDependency"></param>
public KenticoCacheAttribute(string cacheDependency)
{
CacheMinutes = EngineContext.Current.Resolve<AppSettings>().Cache.TTL.GlobalSetting;
CacheEnabled = !EngineContext.Current.Resolve<AppSettings>().Cache.IgnoreCache;
CacheDependencyParameterIndex = -1;
CacheDependency = cacheDependency;
if (String.IsNullOrEmpty(cacheDependency))
ObtainCacheDependencyFrom = KenticoCacheDependencyObtainFrom.NoDependency;
else
{
ObtainCacheDependencyFrom = KenticoCacheDependencyObtainFrom.Static;
}
}
/// <summary>
/// initializes the cache attribute to use a static dependency using multiple depndencies
/// </summary>
/// <param name="cacheDependencystrings">an array of strings</param>
public KenticoCacheAttribute(string[] cacheDependencystrings)
{
CacheMinutes = EngineContext.Current.Resolve<AppSettings>().Cache.TTL.GlobalSetting;
CacheEnabled = !EngineContext.Current.Resolve<AppSettings>().Cache.IgnoreCache;
CacheDependencyParameterIndex = -1;
CacheDependencyStrings = cacheDependencystrings;
ObtainCacheDependencyFrom = KenticoCacheDependencyObtainFrom.MultipleDependenciesStatic;
}
/// <summary>
/// initializes the cache attribute to take the dependency from the input parameter
/// </summary>
/// <param name="cacheDependency">the static string to be used for the cache dependency. you may include {CurrentSiteName} to be replaced with the current site name, and {0} to be replaced with the value passed in as one of the method parameters</param>
/// <param name="cacheDependencyParameterIndex">the index of the parameter in the method parameters that will be used to create the cache dependency key</param>
public KenticoCacheAttribute(string cacheDependency, int cacheDependencyParameterIndex)
{
CacheMinutes = EngineContext.Current.Resolve<AppSettings>().Cache.TTL.GlobalSetting;
CacheEnabled = !EngineContext.Current.Resolve<AppSettings>().Cache.IgnoreCache;
CacheDependencyParameterIndex = cacheDependencyParameterIndex;
CacheDependency = cacheDependency;
if (String.IsNullOrEmpty(cacheDependency))
{
ObtainCacheDependencyFrom = KenticoCacheDependencyObtainFrom.MultipleDependenciesFromParameter;
}
else
{
ObtainCacheDependencyFrom = KenticoCacheDependencyObtainFrom.FromMethodParameter;
}
}
/// <summary>
/// initialize the cache attribute to obtain the cache dependency from the named property of the return object
/// </summary>
/// <param name="cacheDependency">the static string to be used for the cache dependency. you may include {CurrentSiteName} to be replaced with the current site name, and {0} to be replaced with the value in the named parameter </param>
/// <param name="cacheDependencyObjectPropertyName">the name of the property of the return object that will be used to replace the placeholder in the static string to build the cache dependency string</param>
public KenticoCacheAttribute(string cacheDependency, string cacheDependencyObjectPropertyName)
{
CacheMinutes = EngineContext.Current.Resolve<AppSettings>().Cache.TTL.GlobalSetting;
CacheEnabled = !EngineContext.Current.Resolve<AppSettings>().Cache.IgnoreCache;
CacheDependencyParameterIndex = -1;
CacheDependency = cacheDependency;
ObtainCacheDependencyFrom = KenticoCacheDependencyObtainFrom.FromReturnObject;
CacheDependencyObjectProperty = cacheDependencyObjectPropertyName;
}
/// <summary>
/// initialize the cache attribute to obtain the cache dependency from the named property of the return object
/// </summary>
/// <param name="cacheDependency">the static string to be used for the cache dependency. you may include {CurrentSiteName} to be replaced with the current site name, and {0} to be replaced with the value in the named parameter </param>
/// <param name="cacheDependencyParameterIndex"></param>
/// <param name="cacheDependencyObjectPropertyName">the name of the property of the return object that will be used to replace the placeholder in the static string to build the cache dependency string</param>
public KenticoCacheAttribute(string cacheDependency, int cacheDependencyParameterIndex, string cacheDependencyObjectPropertyName)
{
CacheMinutes = EngineContext.Current.Resolve<AppSettings>().Cache.TTL.GlobalSetting;
CacheEnabled = !EngineContext.Current.Resolve<AppSettings>().Cache.IgnoreCache;
CacheDependencyParameterIndex = cacheDependencyParameterIndex;
CacheDependency = cacheDependency;
ObtainCacheDependencyFrom = KenticoCacheDependencyObtainFrom.FromMethodParameterObjectProperty;
CacheDependencyObjectProperty = cacheDependencyObjectPropertyName;
}
public override void CompileTimeInitialize(MethodBase method, AspectInfo aspectInfo)
{
_methodName = method.Name;
}
public override void OnInvoke(MethodInterceptionArgs args)
{
var methodInfo = args.Method as MethodInfo;
if (methodInfo != null && (methodInfo.ReturnType != typeof(void) && CacheEnabled))
{
var cacheKey = BuildCacheKey(args.Arguments);
var cacheSettings = new CacheSettings(CacheMinutes, cacheKey);
var data = CacheHelper.Cache(cs => GetData(cs, args), cacheSettings);
args.ReturnValue = data;
}
else
base.OnInvoke(args);
}
private object GetData(CacheSettings cs, MethodInterceptionArgs args)
{
var data = args.Invoke(args.Arguments);
// Checks whether data was loaded and whether the data should be cached (based on the CacheSettings)
if ((data != null) && cs.Cached)
{
// Sets a cache dependency for the data
// The data is removed from the cache if the objects represented by the dummy key are modified (all user objects in this case)
var dependencyResolver = CacheDependencyFactory.GetDependecyFormatter(ObtainCacheDependencyFrom);
var dependencyString = dependencyResolver.Format(new CacheDependencyFormatParameters()
{
CacheDependencyBase = CacheDependency,
CacheDependencybaseString = CacheDependencyStrings,
InputParameterIndex = CacheDependencyParameterIndex,
ReturnParameterName = CacheDependencyObjectProperty,
InputParameterData = args,
ReturnParameterData = data
});
cs.CacheDependency = CacheHelper.GetCacheDependency(dependencyString);
}
return data;
}
private string BuildCacheKey(Arguments arguments)
{
var sb = new StringBuilder();
sb.Append(_methodName);
foreach (var argument in arguments.ToArray())
{
sb.Append(argument == null ? "_" : argument.ToString());
}
sb.Append(String.Format("{0}_{1}", SiteContext.CurrentSiteName,
SiteContext.CurrentSite.DefaultVisitorCulture));
return sb.ToString();
}
}
Any help would be appreciated!

So it turns out that the issue is with these lines of code in the constructors:
CacheMinutes = EngineContext.Current.Resolve<AppSettings>().Cache.TTL.GlobalSetting;
CacheEnabled = !EngineContext.Current.Resolve<AppSettings>().Cache.IgnoreCache;
When PostSharp runs, The dependencyInjection framework has not yet been initialised, so the execution fails. It's strange that it was working before, but hey. I moved this code into the OnInvoke method, which should only run when the DI Enginecontext has been initialised :
public override void OnInvoke(MethodInterceptionArgs args)
{
CacheMinutes = EngineContext.Current.Resolve<AppSettings>().Cache.TTL.GlobalSetting;
CacheEnabled = !EngineContext.Current.Resolve<AppSettings>().Cache.IgnoreCache;
var methodInfo = args.Method as MethodInfo;
......

Get the exact type as property in C# class

Sorry for the general title but it's a bit hard to explain in few words what is my problem currently.
So I have a simple class factory like this:
public Model Construct<T>(T param) where T : IModelable
{
new Model {Resource = param};
return n;
}
The Model class looks like this:
public class Model
{
public object Resource { get; set; }
}
The problem is, that you can see, is the Resource is currently an object. And I would like that Resource should be the type, what is get from the Construct and not lost the type-safe...
I tried to solve it with type parameter but it fails, because I can extend Model class with type parameter but what if I would like to store it to a simple class repository?
Then Construct will work, but if I would like to get the instanced class from the repository, I have to declare the type paramter again like:
Repository.Get<Model<Spaceship>>(0) .... and of course it's wrong because I would like that Model itself knows, what type of Resource has been added in Construct.
Does anybody any idea how to handle this?
The whole code currently look like this:
/// <summary>
/// Class Repository
/// </summary>
public sealed class Repository
{
/// <summary>
/// The _lock
/// </summary>
private static readonly object _lock = new object();
/// <summary>
/// The _syncroot
/// </summary>
private static readonly object _syncroot = new object();
/// <summary>
/// The _instance
/// </summary>
private static volatile Repository _instance;
/// <summary>
/// The _dict
/// </summary>
private static readonly Dictionary<int, object> _dict
= new Dictionary<int, object>();
/// <summary>
/// Prevents a default data of the <see cref="Repository" /> class from being created.
/// </summary>
private Repository()
{
}
/// <summary>
/// Gets the items.
/// </summary>
/// <value>The items.</value>
public static Repository Data
{
get
{
if (_instance == null)
{
lock (_lock)
{
if (_instance == null) _instance = new Repository();
}
}
return _instance;
}
}
/// <summary>
/// Allocates the specified id.
/// </summary>
/// <param name="id">The id.</param>
/// <param name="parameter">The parameter.</param>
/// <resource name="id">The id.</resource>
/// <resource name="parameter">The parameter.</resource>
public void Allocate(int id, object parameter)
{
lock (_syncroot)
{
_dict.Add(id, parameter);
}
}
/// <summary>
/// Gets the specified id.
/// </summary>
/// <typeparam name="T">The type of the tref.</typeparam>
/// <param name="id">The id.</param>
/// <returns>``0.</returns>
/// <resource name="id">The id.</resource>
public T Get<T>(int id)
{
lock (_syncroot)
{
return (T) _dict[id];
}
}
}
/// <summary>
/// Class IModelFactory
/// </summary>
public sealed class ModelFactory
{
/// <summary>
/// The _lock
/// </summary>
private static readonly object _lock = new object();
/// <summary>
/// The _instance
/// </summary>
private static volatile ModelFactory _instance;
/// <summary>
/// Prevents a default instance of the <see cref="ModelFactory" /> class from being created.
/// </summary>
private ModelFactory()
{
}
/// <summary>
/// Gets the data.
/// </summary>
/// <value>The data.</value>
public static ModelFactory Data
{
get
{
if (_instance == null)
{
lock (_lock)
{
if (_instance == null) _instance = new ModelFactory();
}
}
return _instance;
}
}
/// <summary>
/// Constructs the specified param.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="param">The param.</param>
/// <returns>Model{``0}.</returns>
public Model Construct<T>(T param) where T : IModelable
{
var n = new Model {Resource = param};
return n;
}
}
/// <summary>
/// Class Model
/// </summary>
/// <typeparam name="T"></typeparam>
public class Model
{
public object Resource { get; set; }
}
/// <summary>
/// Interface IModelable
/// </summary>
public interface IModelable
{
/// <summary>
/// Gets or sets the mass.
/// </summary>
/// <value>The mass.</value>
float Mass { get; set; }
}
/// <summary>
/// Class spaceship
/// </summary>
public class Spaceship : IModelable
{
/// <summary>
/// Gets or sets the mass.
/// </summary>
/// <value>The mass.</value>
public float Mass { get; set; }
}
So the problem will be lighted here:
Add to the Repository:
Repository.Data.Allocate(1, ModelFactory.Data.Construct(new Spaceship()));
It's okay, but after:
var test_variable = Repository.Data.Get<Model>(1);
So now I have a non type-safe object from a type parameter, I don't know, that what type of class has been stored with the c model construction.
I'm very thankful for the suggestions of using type paramter on the Model class as well, but than it will come up another problem, because I have to change the Get function with it:
var test_variable = Repository.Data.Get<Model<Spaceship>>(1);
But that's definitely wrong, because I won't know, that what kind of type of class has been stored in the model..., so I would like to achieve to avoid this type parameter definition when I would like to load the instance from the Repository.

You can solve this by making your Model class generic, like this:
public class Model<T>
{
public T Resource { get; set; }
}
Then, your Construct method could work like this:
public Model<T> Construct<T>(T param) where T : IModelable<T>
{
return new Model<T>() {Resource = param};
}

You probably need a generic type in the model class:
public class Model<T>
{
public T Resource { get; set; }
}

This sort of structure is one approach you could take:
public Model<T> Construct<T>(T param) where T : IModelable
{
var n = new Model<T> {Resource = param};
return n;
}
public class Model<T> : IModel<T> where T : IModelable
{
public T Resource { get; set; }
}
public interface IModel<out T> where T : IModelable
{
T Resource { get; }
}
This covariant interface allows you to refer to the types more generically where you wish, in the same way that you can pass an IEnumerable<string> into something expecting an IEnumerable<object>.
IModel<Spaceship> shipModel = // whatever
IModel<IModelable> model = shipModel;
//or even:
List<Model<Spaceship>> shipModels = // whatever
IEnumerable<IModel<IModelable>> models = shipModels;

Strange issue using PropertyInfo in C#

I have a class like so:
public class CompanyData
{
# region Properties
/// <summary>
/// string CompanyNumber
/// </summary>
private string strCompanyNumber;
/// <summary>
/// string CompanyName
/// </summary>
private string strCompanyName;
[Info("companynumber")]
public string CompanyNumber
{
get
{
return this.strCompanyNumber;
}
set
{
this.strCompanyNumber = value;
}
}
/// <summary>
/// Gets or sets CompanyName
/// </summary>
[Info("companyName")]
public string CompanyName
{
get
{
return this.strCompanyName;
}
set
{
this.strCompanyName = value;
}
}
/// <summary>
/// Initializes a new instance of the CompanyData class
/// </summary>
public CompanyData()
{
}
/// <summary>
/// Initializes a new instance of the CompanyData class
/// </summary>
/// <param name="other"> object company data</param>
public CompanyData(CompanyData other)
{
this.Init(other);
}
/// <summary>
/// sets the Company data attributes
/// </summary>
/// <param name="other">object company data</param>
protected void Init(CompanyData other)
{
this.CompanyNumber = other.CompanyNumber;
this.CompanyName = other.CompanyName;
}
/// <summary>
/// Getting array of entity properties
/// </summary>
/// <returns>An array of PropertyInformation</returns>
public PropertyInfo[] GetEntityProperties()
{
PropertyInfo[] thisPropertyInfo;
thisPropertyInfo = this.GetType().GetProperties();
return thisPropertyInfo;
}
}
A csv file is read and a collection of CompanyData objects is created
In this method I am trying to get properties and values:
private void GetPropertiesAndValues(List<CompanyData> resList)
{
foreach (CompanyData resRow in resList)
{
this.getProperties = resRow.ExternalSyncEntity.GetEntityProperties();
this.getValues = resRow.ExternalSyncEntity.GetEntityValue(resRow.ExternalSyncEntity);
}
}
Here's the problem, for the first object the GetEntityProperties() returns the CompanyNumber as the first element in the array. For the remaining objects it returns CompanyName as the first element.
Why is the sequence not consistent?
Regards.

The Type.GetProperties() does not return ordered result.
The GetProperties method does not return properties in a particular order, such as alphabetical or declaration order. Your code must not depend on the order in which properties are returned, because that order varies.
If you want to use ordered/consistent result, it is better to sort the returned array.

Disable save button when validation fails

As you can likely see from the title, I am about to ask something which has been asked many times before. But still, after reading all these other questions, I cannot find a decent solution to my problem.
I have a model class with basic validation:
partial class Player : IDataErrorInfo
{
public bool CanSave { get; set; }
public string this[string columnName]
{
get
{
string result = null;
if (columnName == "Firstname")
{
if (String.IsNullOrWhiteSpace(Firstname))
{
result = "Geef een voornaam in";
}
}
if (columnName == "Lastname")
{
if (String.IsNullOrWhiteSpace(Lastname))
{
result = "Geef een familienaam in";
}
}
if (columnName == "Email")
{
try
{
MailAddress email = new MailAddress(Email);
}
catch (FormatException)
{
result = "Geef een geldig e-mailadres in";
}
}
if (columnName == "Birthdate")
{
if (Birthdate.Value.Date >= DateTime.Now.Date)
{
result = "Geef een geldige geboortedatum in";
}
}
CanSave = true; // this line is wrong
return result;
}
}
public string Error { get { throw new NotImplementedException();} }
}
This validation is done everytime the property changes (so everytime the user types a character in the textbox):
<TextBox Text="{Binding CurrentPlayer.Firstname, ValidatesOnDataErrors=True, UpdateSourceTrigger=PropertyChanged}" VerticalAlignment="Top" Width="137" IsEnabled="{Binding Editing}" Grid.Row="1"/>
This works perfect. The validation occurs (the PropertyChanged code for the binding is done in the VM on the CurrentPlayer property, which is an object of Player).
What I would like to do now is disable the save button when the validation fails.
First of all, the easiest solutions seems to be found in this thread:
Enable Disable save button during Validation using IDataErrorInfo
If I want to follow the accepted solution, I'd have to write my
validation code twice, as I cannot simply use the indexer. Writing
double code is absolutely not what I want, so that's not a solution
to my problem.
The second answer on that thread sounded very promising as first,
but the problem is that I have multiple fields that have to be
validated. That way, everything relies on the last checked property
(so if that field is filled in correctly, CanSave will be true, even
though there are other fields which are still invalid).
One more solution I've found is using an ErrorCount property. But as I'm validating at each property change (and so at each typed character), this isn't possible too - how could I know when to increase/decrease the ErrorCount?
What would be the best way to solve this problem?
Thanks

This article http://www.asp.net/mvc/tutorials/older-versions/models-%28data%29/validating-with-the-idataerrorinfo-interface-cs moves the individual validation into the properties:
public partial class Player : IDataErrorInfo
{
Dictionary<string, string> _errorInfo;
public Player()
{
_errorInfo = new Dictionary<string, string>();
}
public bool CanSave { get { return _errorInfo.Count == 0; }
public string this[string columnName]
{
get
{
return _errorInfo.ContainsKey(columnName) ? _errorInfo[columnName] : null;
}
}
public string FirstName
{
get { return _firstName;}
set
{
if (String.IsNullOrWhiteSpace(value))
_errorInfo.AddOrUpdate("FirstName", "Geef een voornaam in");
else
{
_errorInfo.Remove("FirstName");
_firstName = value;
}
}
}
}
(you would have to handle the Dictionary AddOrUpdate extension method). This is similar to your error count idea.

I've implemented the map approach shown in my comment above, in C# this is called a Dictionary in which I am using anonymous methods to do the validation:
partial class Player : IDataErrorInfo
{
private delegate string Validation(string value);
private Dictionary<string, Validation> columnValidations;
public List<string> Errors;
public Player()
{
columnValidations = new Dictionary<string, Validation>();
columnValidations["Firstname"] = delegate (string value) {
return String.IsNullOrWhiteSpace(Firstname) ? "Geef een voornaam in" : null;
}; // Add the others...
errors = new List<string>();
}
public bool CanSave { get { return Errors.Count == 0; } }
public string this[string columnName]
{
get { return this.GetProperty(columnName); }
set
{
var error = columnValidations[columnName](value);
if (String.IsNullOrWhiteSpace(error))
errors.Add(error);
else
this.SetProperty(columnName, value);
}
}
}

This approach works with Data Annotations. You can also bind the "IsValid" property to a Save button to enable/disable.
public abstract class ObservableBase : INotifyPropertyChanged, IDataErrorInfo
{
#region Members
private readonly Dictionary<string, string> errors = new Dictionary<string, string>();
#endregion
#region Events
/// <summary>
/// Property Changed Event
/// </summary>
public event PropertyChangedEventHandler PropertyChanged;
#endregion
#region Protected Methods
/// <summary>
/// Get the string name for the property
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="expression"></param>
/// <returns></returns>
protected string GetPropertyName<T>(Expression<Func<T>> expression)
{
var memberExpression = (MemberExpression) expression.Body;
return memberExpression.Member.Name;
}
/// <summary>
/// Notify Property Changed (Shorted method name)
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="expression"></param>
protected virtual void Notify<T>(Expression<Func<T>> expression)
{
string propertyName = this.GetPropertyName(expression);
PropertyChangedEventHandler handler = this.PropertyChanged;
handler?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
/// <summary>
/// Called when [property changed].
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="expression">The expression.</param>
protected virtual void OnPropertyChanged<T>(Expression<Func<T>> expression)
{
string propertyName = this.GetPropertyName(expression);
PropertyChangedEventHandler handler = this.PropertyChanged;
handler?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
#endregion
#region Properties
/// <summary>
/// Gets an error message indicating what is wrong with this object.
/// </summary>
public string Error => null;
/// <summary>
/// Returns true if ... is valid.
/// </summary>
/// <value>
/// <c>true</c> if this instance is valid; otherwise, <c>false</c>.
/// </value>
public bool IsValid => this.errors.Count == 0;
#endregion
#region Indexer
/// <summary>
/// Gets the <see cref="System.String"/> with the specified column name.
/// </summary>
/// <value>
/// The <see cref="System.String"/>.
/// </value>
/// <param name="columnName">Name of the column.</param>
/// <returns></returns>
public string this[string columnName]
{
get
{
var validationResults = new List<ValidationResult>();
string error = null;
if (Validator.TryValidateProperty(GetType().GetProperty(columnName).GetValue(this), new ValidationContext(this) { MemberName = columnName }, validationResults))
{
this.errors.Remove(columnName);
}
else
{
error = validationResults.First().ErrorMessage;
if (this.errors.ContainsKey(columnName))
{
this.errors[columnName] = error;
}
else
{
this.errors.Add(columnName, error);
}
}
this.OnPropertyChanged(() => this.IsValid);
return error;
}
}
#endregion
}