Parsing and output the results

I am working on a windows application using C#.
I have a textbox and a button named Parse. After
typing in the text and clicking the button it
should output the number of times each letter
appears

for example if I type

“Sweet”

it should output

There are 1 Ss
There are 1 Ws
There are 2 Es
There are 1 Ts

case sensitivity is not an issue. The result are to be displayed in a another UI control which is scrollable.