Money Convertion

Question

I am reading a value from datareader and displaying it into textbox. Say i am reading the value as 20.3421
from database and I want to display it as $20.34 in textbox (money format).
My code is given below.

txtCashAmount.Text = sdrData["cus_cur_MaximumCashAmount"];

Note: sdrData is the name of my sqldatareader