DAX - Calculating Sales through prior month end

Hello,

I am fairly new to DAX and I am struggling in creating a measure that calculates the sum of sales through the prior month end. I have been able to calculate year to date sales but I only want my data to show through the prior month end. I want to have some visuals populate automatically in powerbi that will only show data year to date through the prior month end. Currently I would have to go in and adjust the filter on the visuals each month to get this same result.

Please let me know if you need an example of my data.

Thanks,

-Robert