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Alternative
Tip/Trick
Posted 26 Jan 2012

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Alternative to Activator.CreateInstance

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26 Jan 2012CPOL
The final solution after much debate and optimization:public class DynamicInitializer { static readonly Dictionary> list = new Dictionary>(); public static T New() where T : class { return New(typeof...

The final solution after much debate and optimization:


C#
public class DynamicInitializer
    {
        static readonly Dictionary<string, Func<object>> list = new Dictionary<string, Func<object>>();

        public static T New<T>() where T : class 
        {
            return New(typeof (T)) as T;
        }

        public static object New(Type type)
        {
            if (list.ContainsKey(type.Name)) return list[type.Name];

            Func<object> method = Expression.Lambda<Func<object>>(Expression.Block(type, new Expression[] { Expression.New(type) })).Compile();
            list.Add(type.Name, method);
            return method();
        }
    }

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

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About the Author

Dean Oliver
Software Developer BBD Johannesburg
South Africa South Africa
Bsc (Hons) Business Information Systems.
MCTS: Web Applications Development with Microsoft .NET Framework 4
MCTS: Windows Communication Foundation Development with Microsoft .NET Framework 4
MCTS: Accessing Data with Microsoft .NET Framework 4
Microsoft Certified Professional Developer Certification.

Comments and Discussions

 
GeneralRe: Perhaps it would make it completely obvious looking at the c... Pin
Andrew Rissing26-Jan-12 7:46
MemberAndrew Rissing26-Jan-12 7:46 
GeneralRe: If you use TryGetValue, it uses an out parameter to set the ... Pin
Andrew Rissing26-Jan-12 7:33
MemberAndrew Rissing26-Jan-12 7:33 
GeneralRe: thanks Andrew appreciate that. Why is it quicker though? Pin
Dean Oliver26-Jan-12 6:50
MemberDean Oliver26-Jan-12 6:50 
thanks Andrew appreciate that. Why is it quicker though?
GeneralRe: If you do update this, I'd recommend using "TryGetValue" rat... Pin
Andrew Rissing26-Jan-12 6:13
MemberAndrew Rissing26-Jan-12 6:13 
GeneralRe: No problem. Pin
Paulo Zemek26-Jan-12 6:02
mvaPaulo Zemek26-Jan-12 6:02 
GeneralI think this last version is almost OK. In fact, if you know... Pin
Paulo Zemek26-Jan-12 4:59
mvaPaulo Zemek26-Jan-12 4:59 
GeneralRe: Sorry Paulo I actually accidentally posted the incorrect ver... Pin
Dean Oliver26-Jan-12 5:42
MemberDean Oliver26-Jan-12 5:42 
GeneralBased on a comment by nonexisto, I realized that the constra... Pin
Andrew Rissing26-Jan-12 4:49
MemberAndrew Rissing26-Jan-12 4:49 

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