Delphi - Drag and Drop .txt Files in TMemo

Question

I'm Trying to drag and drop text files into my Delphi app memo1 and load the text. Just like what notepad.exe does ! when dragging any file it loads the text inside of it. but i am trying to only load specified file extension ! to accept loading on memo1.text.

Example: when dragging text.txt file to memo1 it loads the text inside of test.txt but when dragging .exe into memo1 nothing happens or just display error message.

I searched Google and tried my self but i have no answers to my question ;c .

any help will be much appreciated since i got no idea about drag and dropping text into memo.