Pangram checker

You are encouraged to solve this task according to the task description, using any language you may know.
A pangram is a sentence that contains all the letters of the English alphabet at least once.

For example:   The quick brown fox jumps over the lazy dog.



Task

Write a function or method to check a sentence to see if it is a   pangram   (or not)   and show its use.



Related tasks

   determine if a string has all the same characters
   determine if a string has all unique characters


Gui, -MinimizeBox
Gui, Add, Edit, w300 r5 vText
Gui, Add, Button, x105 w100 Default, Check Pangram
Gui, Show,, Pangram Checker
Return
 
GuiClose:
    ExitApp
Return
 
ButtonCheckPangram:
    Gui, Submit, NoHide
    Loop, 26
        If Not InStr(Text, Char := Chr(64 + A_Index)) {
            MsgBox,, Pangram, Character %Char% is missing!
            Return
        }
    MsgBox,, Pangram, OK`, this is a Pangram!
Return