Comments on: Using Reflection in C# to Figure Out if an Integer List Has Values http://peterkellner.net/2009/06/01/csharp-reflection-integer-list-generic/ Specializing in Microsoft Web and Database and Sync Technologies Wed, 08 Sep 2010 06:48:44 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: Peter http://peterkellner.net/2009/06/01/csharp-reflection-integer-list-generic/comment-page-1/#comment-24853 Peter Tue, 02 Jun 2009 12:52:02 +0000 http://peterkellner.net/2009/06/01/csharp-reflection-integer-list-generic/#comment-24853 Thanks Geoff for the tip. My problem is that I don't know ahead of time it is of type List. Is there a way around that? Thanks Geoff for the tip. My problem is that I don’t know ahead of time it is of type List. Is there a way around that?

]]> By: geoffrey.mcgill http://peterkellner.net/2009/06/01/csharp-reflection-integer-list-generic/comment-page-1/#comment-24852 geoffrey.mcgill Tue, 02 Jun 2009 07:58:16 +0000 http://peterkellner.net/2009/06/01/csharp-reflection-integer-list-generic/#comment-24852 Here's a general purpose Lambda Expression Extension Method that simplifies the process of getting a Property value. This should also perform better. Extension Method ----------------- public static Func GetProperty(this Type self, string name) { ParameterExpression parameter = Expression.Parameter(typeof(X), "obj"); MemberExpression property = Expression.Property(parameter, name); return (Func)Expression.Lambda(typeof(Func), property, parameter).Compile(); } Usage -------------------- CompanyQuery query = new CompanyQuery { CompanyTypeIds = new List { 1, 2, 3, 4 } }; Type type = typeof(CompanyQuery); Func<CompanyQuery, List> getList = type.GetProperty<CompanyQuery, List>("CompanyTypeIds"); List ids = getList(query); bool forceNoCompile = (ids != null && ids.Count > 0); Hope this helps. Here’s a general purpose Lambda Expression Extension Method that simplifies the process of getting a Property value. This should also perform better.

Extension Method
—————–
public static Func GetProperty(this Type self, string name)
{
ParameterExpression parameter = Expression.Parameter(typeof(X), “obj”);
MemberExpression property = Expression.Property(parameter, name);
return (Func)Expression.Lambda(typeof(Func), property, parameter).Compile();
}

Usage
——————–
CompanyQuery query = new CompanyQuery { CompanyTypeIds = new List { 1, 2, 3, 4 } };

Type type = typeof(CompanyQuery);

Func<CompanyQuery, List> getList = type.GetProperty<CompanyQuery, List>(“CompanyTypeIds”);

List ids = getList(query);

bool forceNoCompile = (ids != null && ids.Count > 0);

Hope this helps.

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