ASP.NET MVC Html.ValidationSummary(true) does not display model errors

I believe the way the ValidationSummary flag works is it will only display ModelErrors for string.empty as the key. Otherwise it is assumed it is a property error. The custom error you’re adding has the key ‘error’ so it will not display in when you call ValidationSummary(true). You need to add your custom error message … Read more

ModelState.AddModelError – How can I add an error that isn’t for a property?

I eventually stumbled upon an example of the usage I was looking for – to assign an error to the Model in general, rather than one of it’s properties, as usual you call: ModelState.AddModelError(string key, string errorMessage); but use an empty string for the key: ModelState.AddModelError(string.Empty, “There is something wrong with Foo.”); The error message … Read more