Allow Percentage Only at textbox

Does anyone knows how to code to format the textbox to accept only percentage. (3 digits, 1 decimal point, 2 digits) ? i also want to be able to set the limit to 100.00.

heres some code to only accept numbers and a decimal point...hope this help.

VB Code:

Dim KeyAscii As Integer
        KeyAscii = Asc(e.KeyChar)
        'only allow numbers, a single decimal point, backspace  or enter        
        Select Case KeyAscii
            Case Asc("0") To Asc("9"), Asc(ControlChars.Back), Asc("-")
                'acceptable(keystrokes)
                e.Handled = False
            Case Asc(".")
                e.Handled = False
            Case Else
                e.Handled = True
        End Select