Why Do Extension Methods Fail with Dynamic Objects and Throw RuntimeBinderExceptions?

Dynamic Objects and Extension Method Resolution Issues

This example demonstrates why calling extension methods on dynamic objects often leads to RuntimeBinderException errors. The code attempts to use First() (presumably LINQ's First() extension method) on a dynamic object (dList) wrapping a List<int>. The failure stems from how the C# compiler and runtime handle extension methods.

In statically-typed code, the compiler meticulously searches for the appropriate extension method based on namespaces and using directives. This methodical search ensures the correct method is found.

However, dynamic objects lack this crucial compile-time information. The Dynamic Language Runtime (DLR) doesn't have access to the original compilation context, including namespaces and using statements. This prevents the DLR from accurately resolving the extension method call at runtime.

Therefore, while dynamic typing offers flexibility in accessing object members at runtime, it inherently lacks the context necessary for reliable dynamic extension method resolution. This limitation explains the RuntimeBinderException.

The above is the detailed content of Why Do Extension Methods Fail with Dynamic Objects and Throw RuntimeBinderExceptions?. For more information, please follow other related articles on the PHP Chinese website!