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copied!<p>Just trying to find out if there was a way to do this, only way I found so far was enforcing it myself, I created an attribute to be added to each class where you supply the name of the fields you need to be unique:</p> <pre><code> [System.AttributeUsage(System.AttributeTargets.Class, AllowMultiple=false,Inherited=true)] public class UniqueAttribute:System.Attribute { private string[] _atts; public string[] KeyFields { get { return _atts; } } public UniqueAttribute(string keyFields) { this._atts = keyFields.Split(new char[]{','}, StringSplitOptions.RemoveEmptyEntries); } } </code></pre> <p>Then in my class I'll add it:</p> <pre><code>[CustomAttributes.Unique("Name")] public class Item: BasePOCO { public string Name{get;set;} [StringLength(250)] public string Description { get; set; } [Required] public String Category { get; set; } [Required] public string UOM { get; set; } [Required] } </code></pre> <p>Finally, I'll add a method in my repository, in the Add method or when Saving Changes like this:</p> <pre><code>private void ValidateDuplicatedKeys(T entity) { var atts = typeof(T).GetCustomAttributes(typeof(UniqueAttribute), true); if (atts == null || atts.Count() < 1) { return; } foreach (var att in atts) { UniqueAttribute uniqueAtt = (UniqueAttribute)att; var newkeyValues = from pi in entity.GetType().GetProperties() join k in uniqueAtt.KeyFields on pi.Name equals k select new { KeyField = k, Value = pi.GetValue(entity, null).ToString() }; foreach (var item in _objectSet) { var keyValues = from pi in item.GetType().GetProperties() join k in uniqueAtt.KeyFields on pi.Name equals k select new { KeyField = k, Value = pi.GetValue(item, null).ToString() }; var exists = keyValues.SequenceEqual(newkeyValues); if (exists) { throw new System.Exception("Duplicated Entry found"); } } } } </code></pre> <p>Not too nice as we need to rely on reflection but this so far is the approach that works for me! =D</p>

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