Set default for DisplayFormatAttribute.ConvertEmptyStringToNull to false
asp.net-mvc-5, asp.net-web-api2, c#
Solution
You need to swap out the `ModelMetadataProvider` with one that sets the `ConvertEmptyStringToNull` to `false`
Such as:
public class EmptyStringAllowedModelMetadataProvider : DataAnnotationsModelMetadataProvider
{
protected override CachedDataAnnotationsModelMetadata CreateMetadataFromPrototype(CachedDataAnnotationsModelMetadata prototype, Func<object> modelAccessor)
{
var metadata = base.CreateMetadataFromPrototype(prototype, modelAccessor);
metadata.ConvertEmptyStringToNull = false;
return metadata;
}
protected override CachedDataAnnotationsModelMetadata CreateMetadataPrototype(IEnumerable<Attribute> attributes, Type containerType, Type modelType, string propertyName)
{
var metadata = base.CreateMetadataPrototype(attributes, containerType, modelType, propertyName);
metadata.ConvertEmptyStringToNull = false;
return metadata;
}
}
You would register in your WebApiConfig like:
`config.Services.Replace(typeof(ModelMetadataProvider), new EmptyStringAllowedModelMetadataProvider());`
This was inspired by https://gist.github.com/nakamura-to/4029706
Problem
I just converted a bunch of web services to Web API2. Now my C# code blows up when the browser sends an empty string and it enters my code converted to null. I have researched global solutions and none that I have found work for me. I can of course set it manually for every string in all my Web API models, but I have scores of models so would prefer a global solution. Been here: string.empty converted to null when passing JSON object to MVC Controller and other pages and attempted to implement each solution, but to no avail. How can I globally set the default for ConvertEmptyStringToNull to false?