Do We Make a Blessing/Berocha When Giving Charity/Tzedaka?

This morning after I gave some charity I thought about this. Normally we make a blessing on any mitzvah we do. Like making a blessing/berocha on lighting the menorah, eating matzah, and blowing the shofar. So if giving charity is a mitzvah, why than no blessing?

The Rashba, who is a commentator on the Talmud, says that in order to make a blessing/berocha a on a mitzvah it must be entirely 100% in our hands. When we give tzedaka it is not totally up to us. We can make the blessing, and then try and hand over the money but there is no guarantee that the person we are giving to will take it. True that this is highly unlikely as most people collecting charity will gladly accept it from you, but nevertheless we can only make a blessing/berocha on that which is 100% in our hands to complete.

For example when we make a blessing on food, the food should be in our hand and at the least in front of us. More than once, when I was younger, I recall making a blessing on water and then pushing the water fountain button and no water came out. With a water fountain it is important to first push the button so we see the water and then make the berocha.