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Categories / C# / LINQ

 

Linq Reflection

using System; using System.Linq; using System.Linq.Expressions; using System.Reflection; namespace WindowsPhoneMvp.Util {     public class Property     {         /// <summary>         /// Returns the string name of a property, this allows type / member safety         /// </summary>         /// <param name="propertyNameLambda">() => obj.Name</param>         /// <returns>Name</returns>         public static string GetFor(Expression<Func<object>> propertyNameLambda)         {             MemberExpression member;             if(propertyNameLambda.Body is UnaryExpression)                 member = ((UnaryExpression)propertyNameLambda.Body).Operand as MemberExpression;             else                 member = propertyNameLambda.Body as MemberExpression;             if (member != null)                 return member.Member.Name;             throw new ArgumentException("Could not determine property name.", "propertyNameLambda");         }         public static string[] GetFor(params Expression<Func<object>>[] propertyNameLambda)         {             return propertyNameLambda                 .Select(property => property.Body)                 .OfType<MemberExpression>()                 .Select(member => member.Member.Name)                 .Concat(propertyNameLambda                     .Select(property => property.Body)                     .OfType<UnaryExpression>()                     .Select(member => member.Operand)                     .OfType<MemberExpression>()                     .Select(member => member.Member.Name))                 .ToArray();         }         /// <summary>         /// Returns the string name of a property, this allows type / member safety         /// </summary>         /// <typeparam name="T">Type of objects who's properties to evaluate</typeparam>         /// <param name="propertyNameLambda">obj => obj.Name</param>         /// <returns>Name</returns>         public static string For<T>(Expression<Func<T, object>> propertyNameLambda)         {             var memberInfo = GetMemberInfo(propertyNameLambda);             if(memberInfo != null)                 return memberInfo.Name;             throw new ArgumentException("Could not determine property name.", "propertyNameLambda");         }         /// <summary>         /// Returns the string name of a property, this allows type / member safety         /// </summary>         /// <remarks>          /// Adding the TRetVal parameter allows more efficient Lambda expressions (doesn't create the Convert(p => p.ID) function)         /// also helps in Generic Type inference         /// </remarks>         public static string For<T, TRetVal>(Expression<Func<T, TRetVal>> propertyNameLambda)         {             var memberInfo = GetMemberInfo(propertyNameLambda);             if(memberInfo != null)                 return memberInfo.Name;             throw new ArgumentException("Could not determine property name.", "propertyNameLambda");         }         static MemberInfo GetMemberInfo<T, TRetVal>(Expression<Func<T, TRetVal>> propertyNameLambda)         {             MemberExpression member;             if(propertyNameLambda.Body is UnaryExpression)                 member = ((UnaryExpression)propertyNameLambda.Body).Operand as MemberExpression;             else                 member = propertyNameLambda.Body as MemberExpression;             return member != null ? member.Member : null;         }         public static PropertyInfo InfoFor<T>(Expression<Func<T, object>> propertyNameLambda)         {             MemberExpression member;             if (propertyNameLambda.Body is UnaryExpression)                 member = ((UnaryExpression)propertyNameLambda.Body).Operand as MemberExpression;             else                 member = propertyNameLambda.Body as MemberExpression;             if (member != null)             {                 return member.Member as PropertyInfo;             }             throw new ArgumentException("Could not determine property name.", "propertyNameLambda");         }     } }