How can I create a generaic ValidationAttribute in C#?
- by sabbour
I'm trying to create a UniqueAttribute using the System.ComponentModel.DataAnnotations.ValidationAttribute
I want this to be generic as in I could pass the Linq DataContext, the table name, the field and validate if the incoming value is unique or not.
Here is a non-compilable code fragment that I'm stuck at right now:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ComponentModel.DataAnnotations;
using System.Data.Linq;
using System.ComponentModel;
namespace LinkDev.Innovation.Miscellaneous.Validation.Attributes
{
public class UniqueAttribute : ValidationAttribute
{
public string Field { get; set; }
public override bool IsValid(object value)
{
string str = (string)value;
if (String.IsNullOrEmpty(str))
return true;
// this is where I'm stuck
return (!Table.Where(entity => entity.Field.Equals(str)).Any());
}
}
}
I should be using this in my model as follows:
[Required]
[StringLength(10)]
[Unique(new DataContext(),"Groups","name")]
public string name { get; set; }
