How to trim spaces when copy paste?

I have multiline textbox now i copy the value from excel cell and paste to multi line textbox.Content is pasted but also paste the empty spaces also.so the content go to upside.so textbox is view like no contents are not available in textbox.

 

Double click the cell and copy the content and paste it paste correctly.but the whole cell is copied the spaces not trimmed(this is for user friendly purpose).