[英]Need help creating extension method in C# with generics and lambda expression
I'm pulling all of the advanced features together for this one, but haven't worked with generics or lambda expressions very much:我将所有的高级功能都整合到了一起,但还没有使用 generics 或 lambda 表达式:
Here's example usage of the method I want to create:这是我要创建的方法的示例用法:
MyClass mc = null;
int x = mc.TryGetOrDefault(z => z.This.That.TheOther); // z is a reference to mc
// the code has not failed at this point and the value of x is 0 (int's default)
// had mc and all of the properties expressed in the lambda expression been initialized
// x would be equal to mc.This.That.TheOther's value
Here's as far as I've gotten, but Visual Studio is complaining:这是据我所知,但 Visual Studio 抱怨:
You haven't made your method generic in TResult
.您还没有在TResult
您的方法通用。 You want something like:你想要这样的东西:
public static TResult TryGetOrDefault<TSource, TResult>
(this TSource obj, Expression<Func<TSource, TResult>> expression)
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