How to set the method?

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Hi,
to figure out how to try to fill a comparison in my method.
I pass the lambda expression to the method via the parameter and then I try to compare it with the found value double.

C#

IndexMax(mapPointList, seznamIndex, point => point.X);

C#

private void IndexMax(List<MapPoint> mapPointList, List<int> seznamIndex, Func<MapPoint, double> lambda)
        {
            double hodnotaMax = mapPointList.Max(lambda);
            int index = mapPointList.FindIndex(lambda == hodnotaMax);//Error	CS0019	Operator '==' cannot be applied to operands of type 'Func<MapPoint, double>' and 'double'	
            seznamIndex.Add(index);
        }

What I have tried:

How can I write a value so that it can be applied?

Thank you

David

Posted 8-Jun-22 22:35pm

dejf111

Updated 9-Jun-22 2:47am

v2

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Richard MacCutchan 9-Jun-22 5:15am

You have not explained what is wrong with the original code and what you are trying to change.

dejf111 9-Jun-22 5:26am

Now that everything is fine, I just want to shorten the code.

Richard MacCutchan 9-Jun-22 5:43am

Shorten it to what?

dejf111 9-Jun-22 5:45am

It is stated there.

dejf111 9-Jun-22 8:30am

I remade the question

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Richard MacCutchan · Answer 1 · 2022-06-09T02:47:00

Solution 1

You need your Func to actually do something, you cannot use it to compare against a simple type. See Func<T,TResult> Delegate (System) | Microsoft Docs[^].

Posted 9-Jun-22 2:47am

Richard MacCutchan

Comments

dejf111 10-Jun-22 1:09am

Thanks, I'm still not smart about it.