DELPHI - How to show enum name as string (TFieldType)

Add System.TypInfo to your uses statement:

var
  i : integer;
  pColumn : TcxGridDBColumn;
begin
  ...
  for i := 0 to pGridView.VisibleColumnCount - 1 do
    begin
      pColumn := TcxGridDBColumn( pGridView.VisibleColumns[i] );

      ShowMessage( pColumn.DataBinding.FieldName + ' , ' + 
                   GetEnumName( TypeInfo(TFieldType), 
                                ord( pColumn.DataBinding.Field.DataType ) ) );
    end;
  ...

Output: