How to customize a caret of TextBox in UWP?

I want to make customized TextBox and I don't know how to customize the caret in UWP.

I thought of these ways to make it:

1. Change the style of the original caret directly
2. Use a rectangle and let it blink, but how to hide the original caret or how to make the new one blink at the same time as the orignal one?
3. Remake a TextBox, but how to do it and make it support IME?

Please help!