I prefer [Fluent Validation][1]:

1. It gives me far better control of my validation rules
2. Doing conditional validation on different properties is so much easier compared to Data Annotations
3. It separates the validation from my view models
4. [Unit testing][2] is far easier compared to Data Annotations
5. It has excellent client side validation support for most standard validation rules


  [1]: https://github.com/JeremySkinner/FluentValidation
  [2]: https://github.com/JeremySkinner/FluentValidation/wiki/g.-Testing

I clearly prefer *Data Annotations* because ...

 1. all validation rules can be configured in **one place in code** (within the model metadata class) and don&#39;t need to be repeated anywhere else.
 2. there is excellent support for **client side validation** (again – without repetition of validation rules!) when using *Data Annotation* attributes.
 3. *Data Annotation* attributes can be **tested** to ensure they&#39;re there.
 4. there are nice **additional validation attributes** created by the community (e.g. [Data Annotations Extensions][1]).


  [1]: https://github.com/srkirkland/DataAnnotationsExtensions

I want to use jackson json library for a generic method as follows:

    public MyRequest&lt;T&gt; tester() {
        TypeReference&lt;MyWrapper&lt;T&gt;&gt; typeRef = new TypeReference&lt;MyWrapper&lt;T&gt;&gt;();  
        MyWrapper&lt;T&gt; requestWrapper = (MyWrapper&lt;T&gt;) JsonConverter.fromJson(jsonRequest, typeRef);
        return requestWrapper.getRequest();
    }

&lt;!--&gt;

    public class MyWrapper&lt;T&gt; {
    
        private MyRequest&lt;T&gt; request;
    
        public MyRequest&lt;T&gt; getRequest() {
            return request;
        }
    
        public void setRequest(MyRequest&lt;T&gt; request) {
            this.request = request;
        }
    }
&lt;!--&gt;
    public class MyRequest&lt;T&gt; {
         private List&lt;T&gt; myobjects;
            
         public void setMyObjects(List&lt;T&gt; ets) {
             this.myobjects = ets;
         }

         @NotNull
         @JsonIgnore
         public T getMyObject() {
             return myobjects.get(0);
         }
    }


Now the problem is that when I call getMyObject() which is inside the request object Jackson returns the nested custom object as a LinkedHashMap. Is there any way in which I specify that T object needs to be returned? For example: if I sent object of type Customer then Customer should be returned from that List?

Jackson and generic type reference

Using Javascript, I want to generate a link to a page. The parameters to the page are in a Javascript array that I serialize in JSON.

So I would like to generate a URL like that :

    http://example.com/?data=&quot;MY_JSON_ARRAY_HERE&quot;

**How do I need to escape my JSON string (array serialized) to include it as a parameter in a URL ?**

If there&#39;s a solution using JQuery I&#39;d love it.

*Note: Yes, the parameters to the page need to be in an array because there are a lot of them. I think I&#39;ll use bit.ly to shorten the links afterwards.*

How to escape a JSON string to have it in a URL?

What are the operative differences between these two validation packages when used for ASP.NET MVC validatation? They seem to have similar objects, all the way to their object names. Is one related to another? What are their differences? In what way do these differences denote different use cases?

* [Fluent Validation][1] (3rd party solution)
* [Data annotations][2] (Microsoft &quot;baked-in&quot;)


  [1]: https://github.com/JeremySkinner/FluentValidation
  [2]: http://www.asp.net/mvc/tutorials/validation-with-the-data-annotation-validators-cs

Fluent Validation vs. Data Annotations

What are the operative differences between these two validation packages when used for ASP.NET MVC validatation? They seem to have similar objects, all the way to their object names. Is one related to another? What are their differences? In what way do these differences denote different use cases?
<ul>
<li>
<a href="https://github.com/JeremySkinner/FluentValidation" target="_blank" rel="noopener noreferrer">Fluent Validation</a> (3rd party solution)
</li>
<li>
<a href="http://www.asp.net/mvc/tutorials/validation-with-the-data-annotation-validators-cs" target="_blank" rel="noopener noreferrer">Data annotations</a> (Microsoft "baked-in")
</li>
</ul>

I am able to get date and time using:

    DateTime now = DateTime.Now;

How can I get the current date and time separately in the DateTime format itself?

I am not using the DateTime picker dialog box in ASP.NET (C#).


How to get the current date without the time?

How can I get all filenames of a directory (and its subdirectorys) without the full path? 
**Directory.GetFiles(...)** returns always the full path! 

Get filenames without path of a specific directory

I don&#39;t know what&#39;s wrong with my machine, but it&#39;s a while that I&#39;m getting the following strange error from ASP.NET (for all my applications).

    Compilation Error

    Description: An error occurred during the compilation of a resource required to service this request. Please review the following specific error details and modify your source code appropriately. 

    Compiler Error Message: The compiler failed with error code -1073741502.


    Show Detailed Compiler Output:


    C:\Windows\SysWOW64\inetsrv&gt; &quot;C:\Windows\Microsoft.NET\Framework\v4.0.30319\csc.exe&quot; /t:library /utf8output /R:&quot;C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\root\75855fbd\1e953b27\assembly\dl3\2689d6b5\f0791420_961fcc01\wnvhtmlconvert.dll&quot; /R:&quot;C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System\v4.0_4.0.0.0__b77a5c561934e089\System.dll&quot; /R:&quot;C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Drawing\v4.0_4.0.0.0__b03f5f7f11d50a3a\System.Drawing.dll&quot; /R:&quot;C:\Windows\Microsoft.Net\assembly\GAC_32\System.Web\v4.0_4.0.0.0__b03f5f7f11d50a3a\System.Web.dll&quot; /R:&quot;C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Web.Entity\v4.0_4.0.0.0__b77a5c561934e089\System.Web.Entity.dll&quot; /R:&quot;C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.ServiceModel.Web\v4.0_4.0.0.0__31bf3856ad364e35\System.ServiceModel.Web.dll&quot; /R:&quot;C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.IdentityModel\v4.0_4.0.0.0__b77a5c561934e089\System.IdentityModel.dll&quot; /R:&quot;C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\root\75855fbd\1e953b27\assembly\dl3\d08c81cd\4d77c01f_961fcc01\AjaxControlToolkit.dll&quot; /R:&quot;C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.ServiceModel.Activation\v4.0_4.0.0.0__31bf3856ad364e35\System.ServiceModel.Activation.dll&quot; /R:&quot;C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Web.ApplicationServices\v4.0_4.0.0.0__31bf3856ad364e35\System.Web.ApplicationServices.dll&quot; ......AND SO ON.....

Facts:

1. Killing worker process fixes the problem temporarily
2. I even reinstalled my .NET framework! It didn&#39;t work.
3. Restarting IIS doesn&#39;t help

What can cause this problem?


ASP.NET strange compilation error

I&#39;m trying to write a regular expression to match anything that isn&#39;t &quot;foo&quot; and &quot;bar&quot;.  I found how to match anything but one word at https://stackoverflow.com/questions/406230/regular-expression-to-match-string-not-containing-a-word but I&#39;m not very skilled with regex and am unsure of how to add a second word to this critera.

Any help would be most appreciated! 


CLARIFICATION:

I wanted to match on anything that wasn&#39;t EXACTLY foo or bar.

Regex to match anything but two words

I haven&#39;t done much with NUnit before, but I just wanted to dump some text to a window in a console type fashion. For example:

```cs
Console.WriteLine(&quot;... some information...&quot;);
```

That won&#39;t work of course because NUnit is driving things.

I&#39;m in the middle of building some unit tests and want to dump a list of variable values for inspection during debug. It isn&#39;t strictly a unit test if I need to do this, I admit that, but it would be convenient.


Replace Console.WriteLine in NUnit

I&#39;m using `AutoMapper` in an `ASP.NET MVC` application. I was told that I should move the `AutoMapper.CreateMap` elsewhere as they have a lot of overhead. I&#39;m not too sure how to design my application to put these calls in just 1 place.

I have a web layer, service layer and a data layer. Each a project of its own. I use `Ninject` to DI everything. I&#39;ll utilize `AutoMapper` in both web and service layers. 

So what are your setup for `AutoMapper`&#39;s CreateMap? Where do you put it? How do you call it?

Where to place AutoMapper.CreateMaps?

I am configuring an MVC 3 project to work on a local install of IIS and came across the following 500 error:

&gt; Handler &quot;PageHandlerFactory-Integrated&quot; has a bad module
&gt; &quot;ManagedPipelineHandler&quot; in its module list.

It turns out that this is because ASP.Net was not completely installed with IIS even though I checked that box in the &quot;Add Feature&quot; dialog.  To fix this, I simply ran the following command at the command prompt

    %windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_regiis.exe -i

If I had been on a 32 bit system, it would have looked like the following:

    %windir%\Microsoft.NET\Framework\v4.0.21006\aspnet_regiis.exe -i

My question is, is there a way to install IIS on a windows 7 box to use .NET 4.0 (MVC 3) without taking this extra step?

How to fix: Handler &quot;PageHandlerFactory-Integrated&quot; has a bad module &quot;ManagedPipelineHandler&quot; in its module list

What is the most natural way to return an empty ActionResult (for child action)?

    public ActionResult TestAction(bool returnValue)
    {
       if (!returnValue)
         return View(EmptyView);
       
       return View(RealView);
    }

One option I can see is to create an empty view and reference it at EmptyView... but may be there is any built-in option?

ASP.NET MVC return empty view

Using ASP.NET MVC I am creating a custom Authorize attribute to take care of some custom authorization logic.  I have looked at a lot of examples and it is pretty straight forward but my question is which method is best to override, AuthorizeCore or OnAuthorization?  I have seen many examples overriding one or the other.  Is there a difference?  

Extend AuthorizeAttribute Override AuthorizeCore or OnAuthorization

I have the following:

    @if (Model.PageMeta.Sidebar == PageMetaSidebar.Small) { Html.RenderPartial(&quot;_SmallSidebar&quot;); }


and in my include file:

    &lt;style &quot;text/css&quot;&gt;
        #sbr { width: 193px; }
        #lft { left: 205px; top: 85px; right:  5px; bottom: 30px; }
        #top { left: 215px; top: 85px; right: 15px; }
        #btm { left: 215px; right: 15px; bottom: 30px; }
        #mdl { left: 215px; top: 85px; right: 15px; bottom: 30px; }
        @media print {
            div#lft {left:10px; right: 10px; top: 0px;}
            div#top {left:20px; right: 20px; top: 0px;}
            div#btm {left:20px; right: 20px; }
            div#mdl {left:20px; right: 20px; top: 0px;}
        }
    }
    &lt;/style&gt;

However this gives me a compile type error:

    _SmallSidebar.cshtml(7): error CS0103: The name &#39;media&#39; does not exist in the current context

Does anyone out there know how I could fix this so it accepts that @media is not something that needs to be evaluated?

How can I specify CSS @media within a razor file?

I&#39;m using `System.ComponentModel.DataAnnotations` to provide validation for my Entity Framework 4.1 project.

For example:
    
    public class Player
    {
        [Required]
        [MaxLength(30)]
        [Display(Name = &quot;Player Name&quot;)]
        public string PlayerName { get; set; }

        [MaxLength(100)]
        [Display(Name = &quot;Player Description&quot;)]
        public string PlayerDescription{ get; set; }
    }

I need to retrieve the `Display.Name` annotation value to show it in a message such as *The chosen &quot;Player Name&quot; is Frank.*

=================================================================================

Another example of why I could need to retrieve annotations:

    var playerNameTextBox = new TextBox();
    playerNameTextBox.MaxLength = GetAnnotation(myPlayer.PlayerName, MaxLength);

How can I do that?

How to retrieve Data Annotations from code? (programmatically)

I have an object graph sprinkled with DataAnnotation attributes, where some properties of objects are classes which themselves have validation attributes, and so on.

In the following scenario:

    public class Employee
    {
        [Required]
        public string Name { get; set; }
    
        [Required]
        public Address Address { get; set; }
    }
    
    public class Address
    {
        [Required]
        public string Line1 { get; set; }
    
        public string Line2 { get; set; }
    
        [Required]
        public string Town { get; set; }
    
        [Required]
        public string PostalCode { get; set; }
    }

If I try to validate an `Employee`&#39;s `Address` with no value for `PostalCode`, then I would like (and expect) an exception, but I get none. Here&#39;s how I&#39;m doing it:

    var employee = new Employee
    {
        Name = &quot;Neil Barnwell&quot;,
        Address = new Address
        {
            Line1 = &quot;My Road&quot;,
            Town = &quot;My Town&quot;,
            PostalCode = &quot;&quot; // &lt;- INVALID!
        }
    };

    Validator.ValidateObject(employee, new ValidationContext(employee, null, null));

What other options do I have with `Validator` that would ensure all properties are validated *recursively*?


DataAnnotations: Recursively validating an entire object graph

I&#39;m running EF 4.2 CF and want to create indexes on certain columns in my POCO objects.

As an example lets say we have this employee class:

    public class Employee
    {
      public int EmployeeID { get; set; }
      public string EmployeeCode { get; set; }
      public string FirstName { get; set; }
      public string LastName { get; set; }
      public DateTime HireDate { get; set; }
    }

We often do searches for employees by their EmployeeCode and since there are a lot of employees it would be nice to have that indexed for performance reasons.

Can we do this with fluent api somehow? or perhaps data annotations?

I know it is possible to execute sql commands something like this:

    context.Database.ExecuteSqlCommand(&quot;CREATE INDEX IX_NAME ON ...&quot;);

I would very much like to avoid raw SQL like that.

i know this does not exist but looking for something along those lines:

    class EmployeeConfiguration : EntityTypeConfiguration&lt;Employee&gt;
        {
            internal EmployeeConfiguration()
            {
                this.HasIndex(e =&gt; e.EmployeeCode)
                    .HasIndex(e =&gt; e.FirstName)
                    .HasIndex(e =&gt; e.LastName);
            }
        }

or maybe using `System.ComponentModel.DataAnnotations` the POCO could look like this (again i know this does not exist):
    
    public class Employee
    {
      public int EmployeeID { get; set; }
      [Indexed]
      public string EmployeeCode { get; set; }
      [Indexed]
      public string FirstName { get; set; }
      [Indexed]
      public string LastName { get; set; }
      public DateTime HireDate { get; set; }
    }


Anyone have any ideas on how to do this, or if there are any plans to implement a way to do this, the code first way?

**UPDATE:** As mentioned in the answer by Robba, this feature is implemented in EF version 6.1

Entity Framework Code First Fluent Api: Adding Indexes to columns

I&#39;m trying to use DataAnnotations in my WPF project to specify a maximum length of strings, with the following:

    using System.ComponentModel.DataAnnotations;

However, I get the error

&gt; The type or namespace name &#39;DataAnnotations&#39; does not exist in the
&gt; namespace &#39;System.ComponentModel&#39; (are you missing an assembly
&gt; reference?)

I&#39;ve seen other examples where `DataAnnotations` *does* exist in this namespace. I&#39;m using C#4. Is there any reason why I can&#39;t use this? What can I do to fix it?

Why can&#39;t I reference System.ComponentModel.DataAnnotations?

I am using Entity Framework 4.3 and using Code Fist.

I have a class 

    public class User
    {
       public int UserId{get;set;}
       public string UserName{get;set;}
    }

How do I tell Entity Framework that UserName has to be unique when creating database table?
I would prefer to use data anotations instead of configuration file if possible.


Entity Framework code first unique column

What I need is a way to conditionally validate fields depending on if other fields are filled in.

Ex. I have a dropdown and a date field that are related.  If none of the fields are set then the form should pass validation.  However, if one of the two fields are set but the other isn&#39;t then the validation should fire, requiring the other field to be set.

I have written custom validation classes but it seems that it is validates on single fields.  Is there a way to set up the validation that I need using the built in validators?  If not, Is there a good way to connect two fields using a custom validator?

Conditional Validation using Fluent Validation

I have a FluentValidator that has multiple properties like zip and county etc. I want to create a rule that takes two properties just like a RuleFor construct

    public class FooArgs
    {
        public string Zip { get; set; }
        public System.Guid CountyId { get; set; }
    }

    public class FooValidator : AbstractValidator&lt;FooArgs&gt;
    {
        RuleFor(m =&gt; m.CountyId).Must(ValidZipCounty).WithMessage(&quot;wrong Zip County&quot;);
    }

This works but I want to pass both Zip and county to the rue in order to validate. What is the best method to achieve this?

FluentValidation rule for multiple properties

I have this **model**

    public class Person
    {
        public int Id { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }  
    }
I want to create a validation where either FirstName or LastName must be filled in by user.
I installed `FluentValidation` and created a **customvalidator class**

    public class PersonValidator:AbstractValidator&lt;Person&gt;
    {
        public PersonValidator()
        {
            RuleFor((person=&gt;person.FirstName)//don&#39;t know how to check if one is empty
        }
    }
To check just one field I could just do `RuleFor(person =&gt; person.FirstName).NotNull();`

But how do I check if one of them is null.

Also, is it possible, once validation is created via `fluentValidation`, use it on the client side to show error?

**Edit1**

        protected void Application_Start()
        {
            AreaRegistration.RegisterAllAreas();

            FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
            RouteConfig.RegisterRoutes(RouteTable.Routes);
            BundleConfig.RegisterBundles(BundleTable.Bundles);
            FluentValidationModelValidatorProvider.Configure();
        }
    //creating validation
    namespace WebApplication1.Models.CustomValidator
    {
        public class PersonValidator:AbstractValidator&lt;Person&gt;
        {
            public PersonValidator()
            {
                RuleFor(m =&gt; m.FirstName).NotEmpty().When(m =&gt; string.IsNullOrEmpty(m.LastName)).WithMessage(&quot;*Either First Name or Last Name is required&quot;);
                RuleFor(m =&gt; m.LastName).NotEmpty().When(m =&gt; string.IsNullOrEmpty(m.FirstName)).WithMessage(&quot;*Either First Name or Last Name is required&quot;);
            }
        }
        
    }
    //model class
    [Validator(typeof(PersonValidator))]
    public class Person
    {
        public Person()
        {
            InterestList = new List&lt;string&gt;();
        }
        public int Id { get; set; }
        public int ContactId { get; set; }
        [RequiredIfEmpty(&quot;LastName&quot;)]
        public string FirstName { get; set; }
        [RequiredIfEmpty(&quot;FirstName&quot;)]
        public string LastName { get; set; }
        public string EmailAddress { get; set; }
        public string Phone { get; set; }
        public string Country { get; set; }
        public List&lt;string&gt; InterestList { get; set; } 
    }
    //view
    @model WebApplication1.Models.Person

    &lt;script src=&quot;@Url.Content(&quot;~/Scripts/jquery-1.8.2.min.js&quot;)&quot;&gt;&lt;/script&gt;
    &lt;script src=&quot;@Url.Content(&quot;~/Scripts/jquery.validate.min.js&quot;)&quot;&gt;&lt;/script&gt;
    &lt;script src=&quot;@Url.Content(&quot;~/Scripts/jquery.validate.unobtrusive.min.js&quot;)&quot;&gt;&lt;/script&gt;
    &lt;script src=&quot;@Url.Content(&quot;~/Scripts/jquery.unobtrusive-ajax.min.js&quot;)&quot; type=&quot;text/javascript&quot;&gt;&lt;/script&gt;
    
    @Html.ValidationSummary(true)
    @using(Html.BeginForm(&quot;AddPerson&quot;,&quot;Person&quot;,FormMethod.Post))
    {
        &lt;div class=&quot;label&quot;&gt;First Name&lt;/div&gt;
        &lt;div class=&quot;input-block-level&quot;&gt;@Html.TextBoxFor(m=&gt;m.FirstName)@Html.ValidationMessageFor(m=&gt;m.FirstName)&lt;/div&gt;
        &lt;br/&gt;
        &lt;div class=&quot;label&quot;&gt;Last Name&lt;/div&gt;
        &lt;div class=&quot;input-block-level&quot;&gt;@Html.TextBoxFor(m=&gt;m.LastName)@Html.ValidationMessageFor(m=&gt;m.LastName)&lt;/div&gt;
        &lt;button type=&quot;submit&quot; class=&quot;btn-primary&quot;&gt;Submit&lt;/button&gt;
    }

FluentValidation: Check if one of two fields are empty

I have a hierarchy of data classes

    public class Base
    {
        // Fields to be validated
    }
    
    public class Derived1 : Base
    {
        // More fields to be validated
    }
    
    public class Derived2 : Base
    {
        // More fields to be validated
    }

What would be the appropriate way to validated Derived1 and Derived2 using FluentValidation framework without duplicating rules for fields of Base class?

Content Type	Original Author	Original Content on Stackoverflow
Question	SiberianGuy	View Question on Stackoverflow
Solution 1 - .Net	Darin Dimitrov	View Answer on Stackoverflow
Solution 2 - .Net	Marius Schulz	View Answer on Stackoverflow

Fluent Validation vs. Data Annotations

.Net Problem Overview

.Net Solutions

Solution 1 - .Net

Solution 2 - .Net

How to escape a JSON string to have it in a URL?

Jackson and generic type reference

Attributions