easy

Alt + o > Mouse > Drag Drop


now for reg mIRC

*.wav:/sound $1 $2-
*.*:/dcc send $1 $2-

is already there, what u wanna do is this

*.*:/YourAlias $1-

then for your alias

Code:
alias YourAlias {
  var %win $1
  var %Drag.drop $2-
  if $chan(%win) { 
     ;chan stuff here
  }
  if $query(%win) { 
     ;query stuff here
  }
  if $chat(%win) { 
     ;chatstuff here
  }
  ; and so on and so forth
}