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copied!<p>I'll post this as a different answer, because it is characteristically different than Code Contracts.</p> <p>One approach you can use to have declarative validation is to use a dictionary or hash table as the property store, and share a utility method to perform validation.</p> <p>For example:</p> <pre><code>// Example attribute class for MaxStringLength public class MaxStringLengthAttribute : Attribute { public int MaxLength { get; set; } public MaxStringLengthAttribute(int length) { this.MaxLength = length; } } // Class using the dictionary store and shared validation routine. public class MyDataClass { private Hashtable properties = new Hashtable(); public string CompanyName { get { return GetValue<string>("CompanyName"); } [MaxStringLength(50)] set { SetValue<string>("CompanyName", value); } } public TResult GetValue<TResult>(string key) { return (TResult)(properties[key] ?? default(TResult)); } public void SetValue<TValue>(string key, TValue value) { // Example retrieving attribute: var attributes = new StackTrace() .GetFrame(1) .GetMethod() .GetCustomAttributes(typeof(MaxStringLengthAttribute), true); // With the attribute in hand, perform validation here... properties[key] = value; } } </code></pre> <p>You can get at the calling property using reflection by working up your stack trace as <a href="http://www.csharp-examples.net/reflection-calling-method-name/" rel="nofollow noreferrer">demonstrated here</a>. Reflect the property attributes, run your validation, and <em>voila!</em> One-liner getter/setters that share a common validation routine.</p> <p>On an aside, this pattern is also convenient because you can design a class to use alternative dictionary-like property stores, such as ViewState or Session <em>(in ASP.NET)</em>, by updating only <code>GetValue</code> and <code>SetValue</code>.</p> <p>One additional note is, should you use this approach, you might consider refactoring validation logic into a validation utility class for shared use among all your types. That should help prevent your data class from getting too bulky in the <code>SetValue</code> method.</p>

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