DbEntityValidationException - How can I easily tell what caused the error

Question

I have a project that uses Entity Framework  While calling SaveChanges on my DbContext  I get the following exception      System Data Entity Validation DbEntityValidationException  Validation   failed for one or more entities  See  EntityValidationErrors  property   for more details    This is all fine and dandy  but I don t want to attach a debugger every time this exception occurs  More over  in production environments I cannot easily attach a debugger so I have to go to great lengths to reproduce these errors    How can I see the details hidden within the DbEntityValidationException

User · Answer

To quickly find a meaningful error message by inspecting the error during debugging:

Add a quick watch for:

((System.Data.Entity.Validation.DbEntityValidationException)$exception).EntityValidationErrors

Drill down into EntityValidationErrors like this:

(collection item e.g. [0]) > ValidationErrors > (collection item e.g. [0]) > ErrorMessage

User · Answer

For Azure Functions we use this simple extension to Microsoft Extensions Logging ILogger   public static class LoggerExtensions       public static void Error this ILogger logger  string message  Exception exception                if  exception is DbEntityValidationException dbException                        message      nValidation Errors                 foreach  var error in dbException EntityValidationErrors SelectMany entity   gt  entity ValidationErrors                                 message       n   Field name   error PropertyName   Error message   error ErrorMessage                                     logger LogError default EventId   exception  message             and example usage    try       do something with request and EF   catch  Exception e        log Error   Failed to create customer due to an exception   e Message    e       return await StringResponseUtil CreateResponse HttpStatusCode InternalServerError  e Message

User · Answer

I think  The actual validation errors  may contain sensitive information  and this could be the reason why Microsoft chose to put them in another place  properties   The solution marked here is practical  but it should be taken with caution   I would prefer to create an extension method  More reasons to this     Keep original stack trace Follow open closed principle  ie   I can use different messages for different kind of logs   In production environments there could be other places  ie   other dbcontext  where a DbEntityValidationException could be thrown

User · Answer

To view the EntityValidationErrors collection  add the following Watch expression to the Watch window     System Data Entity Validation DbEntityValidationException  exception  EntityValidationErrors   I m using visual studio 2013

User · Answer

While you are in debug mode within the catch       block open up the  QuickWatch  window  ctrl alt q  and paste in there     System Data Entity Validation DbEntityValidationException ex  EntityValidationErrors   This will allow you to drill down into the ValidationErrors tree  It s the easiest way I ve found to get instant insight into these errors   For Visual 2012  users who care only about the first error and might not have a catch block  you can even do     System Data Entity Validation DbEntityValidationException  exception  EntityValidationErrors First   ValidationErrors First   ErrorMessage

User · Answer

As Martin indicated  there is more information in the DbEntityValidationResult   I found it useful to get both my POCO class name and property name in each message  and wanted to avoid having to write custom ErrorMessage attributes on all my  Required  tags just for this   The following tweak to Martin s code took care of these details for me      Retrieve the error messages as a list of strings  List lt string gt  errorMessages   new List lt string gt     foreach  DbEntityValidationResult validationResult in ex EntityValidationErrors        string entityName   validationResult Entry Entity GetType   Name      foreach  DbValidationError error in validationResult ValidationErrors                errorMessages Add entityName         error PropertyName          error ErrorMessage

User · Answer

Use try block in your code like   try          Your code           Could also be before try if you know the exception occurs in SaveChanges      context SaveChanges      catch  DbEntityValidationException e        foreach  var eve in e EntityValidationErrors                Console WriteLine  Entity of type    0    in state    1    has the following validation errors                eve Entry Entity GetType   Name  eve Entry State           foreach  var ve in eve ValidationErrors                        Console WriteLine  - Property     0     Error     1                      ve PropertyName  ve ErrorMessage                       throw      You can check the details here as well   http   mattrandle me viewing-entityvalidationerrors-in-visual-studio  Validation failed for one or more entities  See   39 EntityValidationErrors  39  property for more details http   blogs infosupport com improving-dbentityvalidationexception

User · Answer

Actually  this is just the validation issue  EF will validate the entity properties first before making any changes to the database  So  EF will check whether the property s value is out of range  like when you designed the table  Table Column UserName is varchar 20   But  in EF  you entered a value that longer than 20   Or  in other cases  if the column does not allow to be a Null  So  in the validation process  you have to set a value to the not null column  no matter whether you are going to make the change on it  I personally  like the Leniel Macaferi answer  It can show you the detail of the validation issues

User · Answer

The easiest solution is to override SaveChanges on your entities class  You can catch the DbEntityValidationException  unwrap the actual errors and create a new DbEntityValidationException with the improved message    Create a partial class next to your SomethingSomething Context cs file  Use the code at the bottom of this post   That s it  Your implementation will automatically use the overriden SaveChanges without any refactor work    Your exception message will now look like this      System Data Entity Validation DbEntityValidationException  Validation   failed for one or more entities  See  EntityValidationErrors  property   for more details  The validation errors are  The field PhoneNumber   must be a string or array type with a maximum length of  12   The   LastName field is required    You can drop the overridden SaveChanges in any class that inherits from DbContext   public partial class SomethingSomethingEntities       public override int SaveChanges                 try                       return base SaveChanges                      catch  DbEntityValidationException ex                           Retrieve the error messages as a list of strings              var errorMessages   ex EntityValidationErrors                      SelectMany x   gt  x ValidationErrors                       Select x   gt  x ErrorMessage                          Join the list to a single string              var fullErrorMessage   string Join       errorMessages                          Combine the original exception message with the new one              var exceptionMessage   string Concat ex Message    The validation errors are     fullErrorMessage                          Throw a new DbEntityValidationException with the improved exception message              throw new DbEntityValidationException exceptionMessage  ex EntityValidationErrors                       The DbEntityValidationException also contains the entities that caused the validation errors  So if you require even more information  you can change the above code to output information about these entities   See also  http   devillers nl improving-dbentityvalidationexception

[c#] DbEntityValidationException - How can I easily tell what caused the error?

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