Func and lambda question [closed]

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I have a declaration of

void Test (Func<bool> f)

I have 开发者_运维技巧a method like bool getItem(string id)

I can call like Test ( ()=>getItem("123")), why?

I suppose that I can check I need 1 string parameter.

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Func<bool> expects a function that returns a bool. Func<T1> has one output argument, then Func<T1, T2> takes a function with input T1 and output T2. Each successive version allows an additional input argument, with the final generic type being the type of your output argument.

ex.: Func<string, string, bool> would be able to invoke bool DoStuff(string s1, string s2)

Quick Edit to clarify: Test( () => getItem("123")) works because the start of your lambda declaration exposes no input arguments, and getItem returns a boolean.

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because the signature of Test requires the argument be a method that takes no parameters and returns a boolean.

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Your method Test is defined as taking a parameter of Func<bool> which expects a method signature similar to bool Something();

Look at the other Func<> options to see which match what you're trying to accomplish. At the very least you're looking at either Action<string> or Func<bool, string>