Automatically generating data annotations from camel case field names

Question

I am working on a project with a huge number of data tables and displaying them through ASP.net MVC screens.

I find myself writing a lot of simple data annotations like this:

 [Display(Name = "Manager Name")]
 public string ManagerName { get; set; }

 [Display(Name = "Employee Name")]
 public string EmployeeName { get; set; }

 [Display(Name = "Employee No")]
 public string EmployeeNo { get; set; }

 [Display(Name = "Manager Employee No")]
 public string ManagerEmployeeNo { get; set; }

This is getting quite tedious and was wondering if there is a way that I can either add a new attribute that says "convertFromCamel" (or something) or is there a way to override

 @Html.DisplayNameFor(m => Model.First().EmployeeNo)

So that if there is no data annotation it converts the existing field name from camel case.

thanks in advance

Its not a data annotation you need, its a custom DataAnnotationsModelMetadataProvider where you override `CreateMetadata()` to set the ModelMetatdata.DisplayName property — , May 21 '15 at 08:42

score 10 · Accepted Answer · edited May 23 '17 at 12:07

Using a combination of the information found on the blog here, and the excellent camel-case split regex here, I was able to work this out. The concept is that you create a custom flavour of the default DataAnnotationsModelMetadataProvider. In the case where a property does not have a display name already, this custom provider kicks in and creates one for you (with spaces).

First, create a class:

using System;
using System.ComponentModel;
using System.Text.RegularExpressions;
using System.Web.Mvc;

namespace MyProject.Whatever
{
    public class CustomDataAnnotationsModelMetadataProvider : DataAnnotationsModelMetadataProvider
    {
        protected override ModelMetadata GetMetadataForProperty(Func<object> modelAccessor, Type containerType, PropertyDescriptor propertyDescriptor)
        {
            ModelMetadata metadata = base.GetMetadataForProperty(modelAccessor, containerType, propertyDescriptor);
            if (metadata.DisplayName == null)
            {
                metadata.DisplayName = SplitCamelCase(metadata.GetDisplayName());
            }
            return metadata;
        }

        private string SplitCamelCase(string str)
        {
            return Regex.Replace(
                Regex.Replace(
                    str,
                    @"(\P{Ll})(\P{Ll}\p{Ll})",
                    "$1 $2"
                ),
                @"(\p{Ll})(\P{Ll})",
                "$1 $2"
            );
        }
    }
}

Now override the default DataAnnotationsModelMetadataProvider in your Global.asax.cs file by doing the following:

protected void Application_Start()
{
    //Other stuff.
    ...
    ModelMetadataProviders.Current = new CustomDataAnnotationsModelMetadataProvider();
}

Thanks Jamie. I will give that a try in the next day or so. cheers — Lobsterpants, May 21 '15 at 10:05
@Chris - No problem, hope it works for you. Let me know how you get on. — Jamie Dunstan, May 21 '15 at 10:07
thanks for this but I get Cannot implicitly convert type 'CustomDataAnnotationsModelMetadataProvider' to 'System.Web.Mvc.ModelMetadataProvider' — Lobsterpants, May 21 '15 at 10:32
@Chris what version of MVC / .net are you using? I can't seem to replicate the problem on my side. — Jamie Dunstan, May 22 '15 at 07:38
So I finally got time to look at this, the problem was some sort of corrupt references which meant it was not recognising System.Web.ModelBinding.Mvc instead was picking up System.Web.ModelBinding.ModelMetadataProviders All works great now - thanks :) — Lobsterpants, Jul 21 '15 at 11:45

Automatically generating data annotations from camel case field names

1 Answers1