Edit Question - KnowledgeHub

Title Body

Given that I have an IEnumerable<T> , where T is any object, how can I select a specific property from it, given that I know the name of the one of the property names at run time as a string? For example: var externalIEnumerable = DataPassedFromConsumingCode(); // `IEnumerable<T>` string knownPropertyName = "Foo"; var fooSelect = externalIEnumerable.Select(...); In essence, I'm obviously just doing externalIEnumerable.Select(x=> x.Foo); , but I need to perform this Select at runtime, when I don't have control over when it's initially created. -- ANSWER: Based on AlanT's answer, here's what I actually did: public Expression<Func<TItem, object>> SelectExpression<TItem>(string fieldName) { var param = Expression.Parameter(typeof(TItem), "item"); var field = Expression.Property(param, fieldName); return Expression.Lambda<Func<TItem, object>>(field, new ParameterExpression[] { param }); } I kept it as an Expression, because calling Compile caused the IQueryable to be Enumerated, which meant the database was hit unnecessarily. So, to use it, I just do the following: string primaryKey = _map.GetPrimaryKeys(typeof(TOriginator)).Single(); var primaryKeyExpression = SelectExpression<TOriginator>(primaryKey); var primaryKeyResults = query.Select(primaryKeyExpression).ToList();

Tags (comma-separated) Cancel