SQL Server adds empty spaces to value (char) when trying to set null

I am pulling data from SQL Server to my c# project. I have some textboxes that update from page-to-page. I have one textbox in particular that is set up to only accept two characters, which is setup in the database as char(2). If I were to delete those two characters and click my button to update the database and go to the next page, it stores two empty spaces. I need it to just be empty with no spaces. In my other textboxes, this issue does not occur. The database allows the data to be null. I am able to manually enter "null" in the database, but I need it to be done when erasing the two chars and updating it.