Discard feature significance in C# 7.0?

Question

While going through new C# 7.0 features, I stuck up with discard feature. It says:

Discards are local variables which you can a

Answer 1

Many times I've done code along these lines:

TextBox.BackColor = int32.TryParse(TextBox.Text, out int32 _) ? Color.LightGreen : Color.Pink;

Note that this would be part of a larger collection of data, not a standalone thing. The idea is to provide immediate feedback on the validity of each field of the data they are entering.

I use light green and pink rather than the green and red one would expect--the latter colors are dark enough that the text becomes a bit hard to read and the meaning of the lighter versions is still totally obvious.

(In some cases I also have a Color.Yellow to flag something which is not valid but neither is it totally invalid. Say the parser will accept fractions and the field currently contains "2 1". That could be part of "2 1/2" so it's not garbage, but neither is it valid.)