<t>To be honest I don't know how to check the content of the validation errors. Visual Studio shows me that it's an array with 8 objects, so 8 validation errors.<br/>
<br/>
Actually you should see the errors if you drill into that array in Visual studio during debug. But you can also catch the exception and then write out the errors to some logging store or the console:<br/>
<br/>
try<br/>
{<br/>
// Your code...<br/>
// Could also be before try if you know the exception occurs in SaveChanges<br/>
<br/>
context.SaveChanges();<br/>
}<br/>
catch (DbEntityValidationException e)<br/>
{<br/>
foreach (var eve in e.EntityValidationErrors)<br/>
{<br/>
Console.WriteLine("Entity of type \"{0}\" in state \"{1}\" has the following validation errors:",<br/>
eve.Entry.Entity.GetType().Name, eve.Entry.State);<br/>
foreach (var ve in eve.ValidationErrors)<br/>
{<br/>
Console.WriteLine("- Property: \"{0}\", Error: \"{1}\"",<br/>
ve.PropertyName, ve.ErrorMessage);<br/>
}<br/>
}<br/>
throw;<br/>
}<br/>
<br/>
```<br/>
<br/>
`EntityValidationErrors` is a collection which represents the entities which couldn't be validated successfully, and the inner collection `ValidationErrors` per entity is a list of errors on property level.<br/>
<br/>
These validation messages are usually helpful enough to find the source of the problem. <br/>
<br/>
**Edit**<br/>
<br/>
A few slight improvements:<br/>
<br/>
The *value* of the offending property can be included in the inner loop like so:<br/>
<br/>
```<br/>
foreach (var ve in eve.ValidationErrors)<br/>
{<br/>
Console.WriteLine("- Property: \"{0}\", Value: \"{1}\", Error: \"{2}\"",<br/>
ve.PropertyName,<br/>
eve.Entry.CurrentValues.GetValue(ve.PropertyName),<br/>
ve.ErrorMessage);<br/>
}<br/>
<br/>
```<br/>
<br/>
While debugging `Debug.Write` might be preferable over `Console.WriteLine` as it works in all kind of applications, not only console applications (thanks to @Bart for his note in the comments below).<br/>
<br/>
For web applications that are in production and that use **Elmah** for exception logging it tur<br/>
<br/>
*(Réponse tronquée)*</t>
