How can I use >= on the left of a C# switch expression?

Question

I have this Enum:

public enum SIZE
{
    Small = 0,
    Medium = 1,
    Large = 2,
}

I would like to use a C# switch expression but I am not sure how to create the "case" statements:

App.devWidth = App.width switch
{

};

What I want to be able to do is to set the width as follows:

Small = App.width < 700;
Medium = App.width >= 700 && App.width < 1200;
Large = App.width >= 1200;

Is there a way I can put these tests for app width on the left side of the "=>" in a switch?

Answer 1

If you're using C# 8.0, you can use when keyword like below:

App.devWidth = App.width switch
{
    var x when x >= 0   && x < 700  => SIZE.Small,
    var x when x >= 700 && x < 1200 => SIZE.Medium,
    var x when x >= 1200            => SIZE.Large,
    _   => throw new Exception("Invalid width value")   // if width < 0
};

The above code additionally checks if App.width >= 0 and throw an exception if not (not sure whether you require this, but if not, just remove it).

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