[Enhancement][Converter] Add Expression property to MathExpressionConverter and MultiMathExpressionConverter

[GUOLDEV]

Summary

Add Expression property to MathExpressionConverter and MultiMathExpressionConverter. I love this Converter, but based on the way that I normally use it, it would be great to be able to set up the Expression value in the Resouce declaration.

API Changes

Added:

• public string Expression { get; set; } = string.Empty;

Intended Use Case

<xct:MathExpressionConverter x:Key="DivideByTwoConverter" Expression="x/2"  />

Who Will Do The Work?

• I am willing to take this on myself
• Just putting this out there for someone to pick up

[GUOLDEV]

I have pushed a draft PR #1609 to exemplify what I would like to activate. Thoughts? @sattew it would be great to know what you think 👍

[GUOLDEV]

@AndreiMisiukevich @brminnick please let us know what you think, once this ticket is approved I can update the docs and sample 👍

[sattew]

I have pushed a draft PR #1609 to exemplify what I would like to activate. Thoughts? @sattew it would be great to know what you think 👍

Hi)
Honestly, I have no thoughts 🙃 I got your point and I like it. We should add it, I think. Thanks!)

[AndreiMisiukevich]

Approved