Tag Archives: NuGet
NBuilder 6.0.0 Released

Thank you to the contributors who submitted pull requests for the issues that were important to them. A summary of the changes for NBuilder 6 are as follows:

  • Breaking Change: WithConstructor
    • No longer takes an Expression<Func<T>>.
    • Takes a Func<T>.
    • Marked [Obsolete] in favor of WithFactory
    • This change was to address an issue in which the constructor expression was not being reevaluated for each item in a list.
  • Feature: @AdemCatamak Added support for IndexOf as part of the ListBuilder implementation.
var products = new Builder()
    .IndexOf(0, 2, 5)
    .With(x => x.Title = "A special title")
  • Feature: @PureKrome Added support for DateTimeKind to RandomGenerator
var result = randomGenerator.Next(DateTime.MinValue, DateTime.MaxValue, DateTimeKind.Utc);
  • Feature: Added DisablePropertyNamingFor(PropertyInfo) overload to BuilderSettings.
  • Feature: Added TheRest as an extension to the ListBuilder.
var results = new Builder()
        .Do(row => row.String1 = "One")
        .Do(row => row.String1 = "Ten")
  • Bug: Last item in enum is never generated when generating property values randomly.
  • Bug: Lost strong name when porting to .NET Standard.
  • Bug: Non-deterministic behavior when calling TheLast multiple times for the same range.

The Problem

I’ve been struggling for awhile to figure out how to get Entity Framework to set and unset application roles in Sql Server when opening and before closing a connection. The problem is that ConnectionState does not provide a Closing state that fires before a connection is closed.

It was suggested to me to turn of connection pooling. Errrr, no. We want connection pooling for our applications. I also don’t want to have to manually open and close the connection every time I create a DbContext. That’s just messy and irritating.

The next obvious thing to do would be to create a DbConnectionDecorator to wrap the existing database connection and expose the Closing event. This proved to be very difficult because Entity Framework does not expose when and how it opens connections.


The Solution

What’s that you say? I can implement my own EntityFramework Provider? There’s a provider wrapper toolkit I can plug into to do this? Awesome!

Oh wait—that looks really, really, REALLY complicated? You mean I can’t just decorate a single object? I have to decorate a whole family of objects?


Alright, tell you what I’ll do. I’ll implement the provider wrapper using the toolkit as best I can—but then I’m going to strip away everything I don’t actually need. Besides, if I just make the various data related events observable, it’s nothing to Trace the output. And Cacheing can easily be added as a IDbContext Decorator anyway. I don’t really get why that should be done at the Provider level.

Configuring Your Application to use the Provider

To use the new provider, first install the package. At application startup, you’ll need to register the provider and tell it which other provider you are wrapping. The registration process will set the ObservableConnectionFactory as the default connection factory used by EF unless you pass the optional setAsDefault:false.

Consuming the Provider Events

ObservableConnection exposes several new events, including Opening, Opened, Failed, Closing, and Closed. However, to subscribe to those events directly requires that you cast the DbConnection exposed by EF to ObservableDbConnection, which strikes me as a little cumbersome (not to mention a violation of the LSP). My first use case demands that I handle the Opening and Closing events the same way for every DbConnection application-wide. To that end, ObservableDbConnection (and ObservableDbCommand) pushes its event messages onto a static class called Hub.


This code is brand-spanking new and it hasn’t had time to bake yet. I’m using it, but it’s entirely possible that there are unforeseen problems. Feel free to report issues to and/or contribute to the open-source project on BitBucket. Until then, know that it has been rigorously test and that it works on my machine.

works on my machine, starburst

Simple.Validation 0.4.0–Release Notes

New Features

Added an assertion api to the PropertyValidator so that the Properties<T> api can be extended by clients.

The order of operations for the Properties api is as follows: If(), Required(), Assertions().

As an example, customized support for boolean properties was added to the library using the following code:

    public static class BooleanPropertyExtensions
        public static PropertyValidator<TContext, bool> IsTrue<TContext>(this PropertyValidator<TContext, bool>  self)
            self.Assert((t, p) => p);
            return self;

        public static PropertyValidator<TContext, bool> IsFalse<TContext>(this PropertyValidator<TContext, bool> self)
            self.Assert((t, p) => !p);
            return self;

        public static PropertyValidator<TContext, bool?> IsTrue<TContext>(this PropertyValidator<TContext, bool?> self)
            self.Assert((t, p) => p.GetValueOrDefault());
            return self;

        public static PropertyValidator<TContext, bool?> IsFalse<TContext>(this PropertyValidator<TContext, bool?> self)
            self.Assert((t, p) => p.HasValue && !p.Value);
            return self;


Breaking Changes

RangePropertyValidator has been removed. It’s functionality is still available, but it has been entirely replaced by extension methods that use the new Assert() method on the PropertyValidator.

ValidationResultTypes have been completely removed. Then intent for ValidationResult.Type is that it is custom per project.

What’s new in Simple.Validation 0.3.1?

Silverlight 4

The entire Simple.Validation library has been compiled for Silverlight and included in the NuGet package.

Conditional Property Validators

An If() method has been applied to the following property validators:

When If() is called with the required Predicate, the validator will only apply when the condition specified by the Predicate is met.

        public void If_PredicateIsFalse_ShouldNotValidate()
            // Arrange
            var validator = Properties<Employee>
                .For(e => e.Age)
                .If(e => e.Age != -1)

            // Act
            var employee = new Employee()
                Age = -1
            var results = validator.Validate(employee);

            // Assert
            Assert.That(results, Is.Empty);

Simple.Validation v0.2.3

A new release of Simple.Validation is available on NuGet.

The changes include:

While Simple.Data is not intended to focus on property-level validation so much that more complex validation scenarios are difficult, it must be recognized that property-level validation accounts for a large part of validation scenarios. In keeping with the goal of simplicity, Simple.Validation provides some mechanisms for wiring up property-level validations quickly. The Fluent Properties API provides factory methods for creating validators for common property types. When used in conjunction with the CompositeValidator<T> it is a trivial task to get simple property-level validation implemented quickly.

This code is from the Personnel.Sample project included in the source code.

    public class SaveAddressValidator : CompositeValidator<Address>
        public override bool AppliesTo(string rulesSet)
            return rulesSet == RulesSets.Crud.Save;

        protected override IEnumerable<IValidator<Address>> GetInternalValidators()
            yield return Properties<Address>.
                For(a => a.Line1)
                .Length(0, 50)
                .Message("Address Line 1 is required.");

            yield return Properties<Address>
                .For(a => a.Line2)
                .Length(0, 50)
                .Message("Line 2 must be between 0 and 50 characters in length.");

            yield return Properties<Address>
                .For(a => a.Line3)
                .Length(0, 50)
                .Message("Line 3 must be between 0 and 50 characters in length.");

            yield return Properties<Address>
                .For(a => a.PostalCode)
                .Length(0, 20)
                .Message("Postal Code must be between 0 and 20 characters in length.");

            yield return Properties<Address>
                .For(a => a.Country)
                .Length(0, 3)
                .Message("Country must be between 0 and 3 characters in length.");

            yield return Properties<Address>
                .For(a => a.StateOrProvince)
                .Length(0, 50)
                .Message("StateOrProvince must be between 0 and 50 characters in length.");



In this sample, each call to Properties<T>.For() returns an instance of StringPropertyValidator. CompositeValidator will accumulate the results from each of the property-level validators and return them all as a single result set. What about non-string properties?

    public class SaveEmployeeValidator : CompositeValidator<Employee>
        public override bool AppliesTo(string rulesSet)
            return rulesSet == RulesSets.Crud.Save;

        protected override IEnumerable<IValidator<Employee>> GetInternalValidators()
            yield return Properties<Employee>
                .For(e => e.FirstName)
                .Length(3, 50)

            yield return Properties<Employee>
                .For(e => e.LastName)
                .Length(3, 50)

            yield return Properties<Employee>
                .For(e => e.Age)

            yield return Properties<Employee>
                .For(e => e.Address)

            yield return Properties<Employee>
                .For(e => e.ContactInfo)
                .Unique<ContactInfo>(c => c.Type)


Employee.Age is of type Int32. Properties<T>.For() any property that is convertible to IComparable will return an instance of RangePropertyValidator. If the property is a reference type, it will return an instance of ReferencePropertyValidator, and if it’s a collection type it will return an instance of EnumerablePropertyValidator.

ReferencePropertyValidator and EnumerablePropertyValidator are similar in that they support Cascading validation onto the reference or collection property itself. This means that Valdiator.Validate<T> will be called for the value of the reference property, or for each element of the collection property. The results will be accumulated into the overall validator results.

When performing cascade validation, there is some question about the type that should be passed to Validator.Validate<T>. Should it be the declared property type (or declared type of the elements of the collection), or should Simple.Validation use the actual type of the property value (or collection element). By default, Cascade() uses the actual type of the property value or collection element, but you can specify the usage of a base type or interface by using the Cascade<T> overload.

In the Personnel.Sample project EmailAddress inherits ContactInfo. There is an EmailAddressValidator that tests the email address against a regular expression. If an instance of EmailAddress is added to the Employee.ContactInfo collection, should it be validated using the EmailAddressValidator or the ContactInfoValidator? Calling the non-generic Cascade() method will cause it to be validated using EmailAddressValdiator. Calling Cascade<ContactInfo>() will cause it to be validated only by the SaveContactInfoValidator.

Announcing Simple.Validation

My company has graciously allowed me to develop a lightweight validation framework and publish it as open-source. There are other very nice validation frameworks available, so why another one? I wanted to be able to use something with all of the strengths and none of the weaknesses of the existing libraries. Here are my stated goals for the project:

  • Simplicity
  • Get moving with a minimum number of moving parts
  • Support dependency injection
  • Focus on object-level validation
  • Support for common property-level validation
  • Support all application types in a consistent manner
  • Support validation at all application layers in a consistent manner
  • Pluggable Architecture

The api I wanted for usage was very simple. Here’s some code from the LoanApplicationSample project:

    public class LoanApplicationDb
        public void Save(LoanApplication loanApplication)
            Validator.Enforce(loanApplication, "Save");
            // do save logic

        public void Submit(LoanApplication loanApplication)
            Validator.Enforce(loanApplication, "Save", "Submit");
            // do submit logic

Just pass your object to the Valdiator.Enforce() method along with the rules sets you wish to validate against and you are off to the races. Enforce will call Validator.Validate(), check for errors, and throw a ValidationException if it finds any. If it doesn’t find any, it just returns the results of Validate(). If you want to bypass the exception logic, just call Validate() directory.

The above code sample demonstrates how to consume the Validator API, but how do you plug into it? You need to be aware of two components. The first is the IValidator<T> implementation. Here is a sample validator that validates the LoanApplciation against the “Save” rules set.

    public class SaveLoanApplicationValidator : IValidator<LoanApplication>
        public bool AppliesTo(string rulesSet)
            return rulesSet == "Save";

        public IEnumerable<ValidationResult> Validate(LoanApplication value)
            var nameResults = Properties<LoanApplication>
                .For(e => e.Name)
                .Length(2, 100)
                .Message("Name is required.")

            var reasonResults = Properties<LoanApplication>
                .For(e => e.Reason)
                .Length(10, 500)
                .Message("Reason is required.")

            var accumulatedResults = nameResults

            return accumulatedResults;


This validator uses the built-in PropertyValidator fluent syntax. Use of the built-in validators is entirely optional. They are included as a convenience in order to provide support for common property-level validations. Simple.Validation handles the simple stuff for you Smile. Where many validation frameworks fall down is when there is some kind of complex validation. In Simple.Validation, complex scenarios are handled the same way as property-level validation. Here’s an example:

        public IEnumerable<ValidationResult> Validate(LoanApplication value)
            if (someComplexCondition)
                yield return new ValidationResult()
                                     Context = value,
                                     Message = string.Format(messageFormat, arguments),
                                     PropertyName = "PropertyName",
                                     Severity = ValidationResultSeverity.Error,
                                     Type = MyCustomValidationType.SomeComplexConditionError

The ValidationResult is a fairly rich object containing a lot of information about the validation error. The Context is the object being validated. You can (and should) provide a detailed message about the error. PropertyName is not required, but will be useful in many scenarios. Severity has levels of Error, Warning, and Informational. ValidationResult.Type is a property there for arbitrary categorization of validation results.

Okay, so now I’ve written a validator—but how does the static Validator class know about the validator I just wrote?

Validator uses an instance of IValidatorProvider to get the list of validators from the simple. Simple.Validation ships with a DefaultValidatorProvider which you can use as follows:

    public class Configuration
        public void ConfigureValidation()
            var validatorProvider = CreateValidatorProvider();

        private static void RegisterValidators(DefaultValidatorProvider validatorProvider)
            validatorProvider.RegisterValidator(new SaveLoanApplicationValidator());
            validatorProvider.RegisterValidator(new SubmitLoanApplicationValidator());

        private static DefaultValidatorProvider CreateValidatorProvider()
            var validatorProvider = new DefaultValidatorProvider();
            return validatorProvider;

The implementation of DefaultValidatorProvider is naïve, so you are encouraged to use the IValidatorProvider interface as a wrapper around your favorite Dependency Injection framework. We provide a second nuget package called Simple.Validation.Ninject that contains a NinjectValidatorProvider.

We’ve been using Simple.Valdiation internally for awhile and feel pretty good about its release. However, as it hasn’t been published on the public NuGet feed yet, we’re assigning a prelease version of 0.1. We will conform to semantic versioning conventions as outlined in this post from Phil Haack.

So, run Install-Package Simple.Validation from the Visual Studio Package Manager Console and start using the bits! As always, your feedback is much appreciated.

Happy Coding! Open-mouthed smile


I was reading some interesting blogs on the specification pattern today. I was hoping to find a NuGet package, but no such luck. So, I put together the best ideas from the blogs I read and created a new NuGet package called Isg.Specification. Much of this work is not original—my contribution is putting the work of these other developers together in an integrated way and publishing it on NuGet.

Although the write-up of the specification pattern on wikipedia doesn’t mention my specific usage goal, I want to create a parameter object that provides a specification to be used by a LINQ query in EntityFramework. In this way, I can provide a single Get<T>(ParameterObject specification) method to service all Get queries. This simplifies a service interface by removing all the various GetById, GetByName, GetByHasInvoices methods. All that differs between those methods is the predicate applied to the query, so passing the predicate into Get() as a parameter just feels natural. However, I don’t want the caller to be able to specify any predicate they want so using a parameter object that converts itself into a predicate services the purpose of limiting the callers query access as well as simplifying the query API.

Even though my target usage is EntityFramework, and the source code is in the same repository as Isg.EntityFramework, Isg.Specification in no way depends on EntityFramework.

The simplest form of the specification pattern uses simple boolean functions. However, since my target usage is EntityFramework, I needed the functions to be convertible to SQL by the EntityFramework. For this reason, my implementation of ISpecification<T> uses Expression<Func<T, bool>> instead of Func<T, bool> as its signature.

   1:      public interface ISpecification<T>
   2:      {
   3:          Expression<Func<T, bool>> IsSatisfied();
   4:      }


The simplest way to get started using the library is to inherit from CompositeSpecification<T>. Using the same sample DbContext I used for Isg.EntityFramework, here is a sample implementation of a Specification object against Customer:

   1:      public class CustomerSpecification : CompositeSpecification<Customer>
   2:      {
   3:          public string Name { get; set; }
   4:          public bool? HasInvoices { get; set; }
   6:          protected override IEnumerable<Expression<Func<Customer, bool>>> GetExpressions()
   7:          {
   8:              if (!string.IsNullOrWhiteSpace(Name))
   9:                  yield return ByName();
  11:              if (HasInvoices.HasValue)
  12:                  yield return ByHasInvoices();
  13:          }
  15:          private Expression<Func<Customer, bool>> ByHasInvoices()
  16:          {
  17:              if (HasInvoices.Value)
  18:                  return c => c.Invoices.Any();
  19:              return c => !c.Invoices.Any();
  20:          }
  22:          private Expression<Func<Customer, bool>> ByName()
  23:          {
  24:              return c => c.Name.StartsWith(Name);
  25:          }
  26:      }


Usage is pretty easy. ISpecification<T> exposes a single method called IsSatisfied(). Feed the result of this method to a LINQ Where clause and you’re off to the races. CompositeSpecification<T> aggregates the expressions provided by GetExpressions() into a single And-ed expression and uses that for the filter.

In my test cases I create 2 customers, one of whom has invoices and one who does not. You can review the test cases in full here:

Here is sample usage:

   1:          [Test]
   2:          public void HasInvoices()
   3:          {
   4:              // Arrange
   5:              var filter = new CustomerSpecification()
   6:                               {
   7:                                   HasInvoices = true,
   8:                               };
  10:              // Act
  11:              using (var context = new CustomerDbContext())
  12:              {
  13:                  var query = context.Customers
  14:                      .Where(filter.IsSatisfied())
  15:                      .ToList();
  17:                  // Assert
  18:                  Assert.That(query, Has.Count.EqualTo(1));
  19:                  var result = query.Single();
  20:                  Assert.That(result.Name, Is.EqualTo("Dagny Taggart"));
  21:              }
  22:          }
I’ve published Isg.Specification as version 0.1. As always, if you find use for my libraries I would really appreciate your feedback.
Isg.EntityFramework 0.4.2 Released to NuGet

Isg.EntityFramework.Interceptors was renamed to Isg.EntityFramework. The interceptors are still present, but I’ve added some work around EntityFramework Configuration.


  • InterceptorDbContext is obsolete. Please use Isg.EntityFramework.DbContextBase
  • DbContextBase adds support for a ModelConfigurationProvider
  • The default ModelConfigurationProvider scans the assembly that your DbContextBase subclass lives in and finds all instances of EntityTypeConfiguration<> and loads them.
  • I added some extension methods to make specifying a non-identity primary key column and computed column a little more straightforward. The EntityFramework method works fine, but isn’t very discoverable. Now it’s Property(<expression>).IsIdentity(false) and Property(<expression>).Computed().
  • Isg.EntityFramework is built against EntityFramework 4.3

Isg.EntityFramework is growing slowly but surely. I would love to hear your ideas about what features you would like to see.


Isg.Collections Now Includes EachConsecutive().

This morning at #SCNA Michael Feathers (@mfeathers) showcased an interesting Ruby function each_cons(). At first glance I didn’t think the function was all that useful, but then he showed how you could use it to see if a list is sorted. I couldn’t find a .NET implementation anywhere, so I added it to my Isg.Collections NuGet package as EachConsecutive().

The algorithm relies on knowing the count of items in its source enumerable. This requires that the enumerable be materialzied. I didn’t want to create deferred execution on Enumerable, so the extension method operates on ICollection<T> instead of IEnumerable<T>.

Here’s some sample code:

// Arrange: Declare any variables or set up any conditions // required by your test. var array = new[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };

// Act: Perform the activity under test. var isSorted = array.EachConsecutive()
    .All(pair =>
        var left = pair.First();
        var right = pair.Last();
        return left < right;

var isNotSorted = array
    .All(pair =>
                 var left = pair.First();
                 var right = pair.Last();
                 return left < right;

// Assert: Verify that the activity under test had the // expected results Assert.That(isSorted, Is.True);
Assert.That(isNotSorted, Is.False);
Installing all NuGet Packages in the Solution

The benefits of using NuGet to manage your project dependencies should be well-known by now.

If not, read this.

There’s one area where NuGet is still somewhat deficient: Team Workflow.

Ideally, when you begin work on a new solution, you should follow these steps:

1) Get the latest version of the source code.

2) Run a command to install any dependent packages.

3) Build!

It’s step 2 in this process that is causing some trouble. NuGet does offer a command to install packages for a single project, but the developer is required to run this command for each project that has package references. It would be nice if NuGet would install all packages for all projects using packages/repositories.config, but at the time of this writing it will not. However, it is fairly easy to add a powershell function to the NuGet package manager console that will do this for you.

First, you should download the NuGet executable and add its directory to your PATH Environment variable. I placed mine in C:devutilsNuGet<version>. You’ll need to be able to access the executable from the command-line.

Second, you need to identify the expected location of the NuGet Powershell profile. You can do this be launching Visual Studio, opening the Package Manager Console, type $profile, then press enter. The console will show you the expected profile path. In Windows 7 it will probably be: “C:Users<user>DocumentsWindowsPowerShellNuGet_profile.ps1”

Next you need to create a file with that name in that directory.

Next, paste the following powershell code into the file:

function Install-NuGetPackagesForSolution()
    write-host "Installing packages for the following projects:"
    $projects = get-project -all
    foreach($project in $projects)


function Install-NuGetPackagesForProject($project)
    if ($project -eq $null)
        write-host "Project is required."

    $projectName = $project.ProjectName;
    write-host "Checking packages for project $projectName"
    write-host ""
    $projectPath = $project.FullName
    $dir = [System.IO.Path]::GetDirectoryName($projectPath)
    $packagesConfigFileName = [System.IO.Path]::Combine($dir, "packages.config")
    $hasPackagesConfig = [System.IO.File]::Exists($packagesConfigFileName)
    if ($hasPackagesConfig -eq $true)
        write-host "Installing packages for $projectName using $packagesConfigFileName."
        nuget i $packagesConfigFileName -o ./packages


Restart Visual Studio 2010. After the package manager console loads, you should be able to run the Install-NuGetPackagesForSolution command. The command will iterate over each of your projects, check to see if the project contains a packages.config file, and if so run NuGet install against the packages.config.

You may also wish to do this from the PowerShell console outside of visual studio. If you are in the solution root directoy you can run the following two commands:

$files = gci -Filter packages.config -Recurse
$files | ForEach-Object {nuget i $_.FullName -o .packages}