[csharp-netcore] made Validate public

[GregorLamche]

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Fix for: #10408

@mandrean @frankyjuang @shibayan @Blackclaws @lucamazzanti

[Blackclaws]

Hold on, shouldn't they work anyway? Its explicitly implementing an interface.

https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/interfaces/explicit-interface-implementation

Therefore public is not necessary and you can validate it when casting it to IValidatableObject

You can't do:

ModelClassInstance.Validate();

You can do:

(ModelClassInstance as IValidatableObject).Validate();

It might be worth discussing whether the first one is something you'd want

[GregorLamche]

As there is no second interface that has a Validate() signature there is no need for explicitly implementing the interface. The opposite actually, hiding interfaces like this, and then requiring a cast every time you use it, seems like bad practice.

[Blackclaws]

Yeah, I get your point. I don't have any issue with the change, and I see no reason to keep the method private.

[wing328]

@GregTheMad thanks for the contribution, which has been merged into master.