FilesDragDrop

Type POINTAPI
    x As Long
    y As Long
End Type

Type MSG
    hWnd As Long
    message As Long
    wParam As Long
    lParam As Long
    time As Long
    pt As POINTAPI
End Type

'4. You now need to add the following Windows API calls to 
'   the module. Make sure that each API is on one line

Declare Sub DragAcceptFiles Lib "shell32.dll" (ByVal hWnd As Long, ByVal fAccept As Long)
Declare Sub DragFinish Lib "shell32.dll" (ByVal hDrop As Long)
Declare Function DragQueryFile Lib "shell32.dll" Alias "DragQueryFileA" (ByVal hDrop As Long, ByVal UINT As Long, ByVal lpStr As String, ByVal ch As Long) As Long
Declare Function PeekMessage Lib "user32" Alias "PeekMessageA" (lpMsg As MSG, ByVal hWnd As Long, ByVal wMsgFilterMin As Long, ByVal wMsgFilterMax As Long, ByVal wRemoveMsg As Long) As Long
Public Const PM_NOREMOVE = &H0
Public Const PM_NOYIELD = &H2
Public Const PM_REMOVE = &H1
Public Const WM_DROPFILES = &H233

'5. You will now need to add the following procedures to the
'   module.

' This is the sub main procedure, that is called
' for any of the forms are loaded.

Sub Main()
    ' In order for this to function properly you should
    ' place of of your program execution code in
    ' the Sub Main(), Make sure you change the project
    ' startup to sub Main
    Form1.Show
    ' This must be the last line! Nothing gets called
    ' after this
    WatchForFiles
End Sub

Public Sub WatchForFiles()
    ' This subroutine watchs for all of your WM_DROPFILES
    ' messages
    ' Dim Variables
    Dim FileDropMessage As MSG ' Msg Type
    Dim fileDropped As Boolean ' True if Files where dropped
    Dim hDrop As Long ' Pointer to the dropped file structure
    Dim filename As String * 128 ' the dropped filename
    Dim numOfDroppedFiles As Long ' the amount of dropped files
    Dim curFile As Long ' the current file number
    ' loop to keep checking for files
    ' NOTE : Do any code you want to execute before this set
    Do
    ' check for Dropped file messages
    fileDropped = PeekMessage(FileDropMessage, 0, _
        WM_DROPFILES, WM_DROPFILES, PM_REMOVE Or PM_NOYIELD)
    If fileDropped Then
        ' Get the pointer to the dropped file structure
        hDrop = FileDropMessage.wParam
        
        ' Get the toal number of files
        numOfDroppedFiles = DragQueryFile(hDrop, True, _
            filename, 127)
        
        For curFile = 1 To numOfDroppedFiles
            ' Get the file name
            
            ret% = DragQueryFile(hDrop, curFile - 1, filename, 127)
            ' at this pointer you can do what you want with the
            ' filename the filename will be a full qalified path
            
            Form1.lblNumDropped = LTrim$(Str$(numOfDroppedFiles))
            Form1.List1.AddItem filename
        Next curFile
        
        ' We are now done with the structure, tell windows
        ' to discard it
        DragFinish (hDrop)
    End If
    DoEvents
Loop
End Sub

'6. Open up form one. Draw the following 3 command buttons
    1 list box 2 labels - one called "lblNumDropped"

'7. Now open up the code window for form1 and type the 
    following

Private Sub Command1_Click()
' You can turn the form's / controls ability
' to accept the files by passing the hWnd as
' the first parameter and True/False as the
' Second
If Command1.Caption = "&Accept Files" Then
    ' allow the application to accept files
    DragAcceptFiles Form1.hWnd, True
    Command1.Caption = "&Do Not Accept"
Else
    DragAcceptFiles Form1.hWnd, False
    Command1.Caption = "&Accept Files"
End If
End Sub

Private Sub Command2_Click()
' Clears the contents of the list box
List1.Clear
End Sub

Private Sub Command3_Click()
' End the program
End
End Sub

Private Sub Form_Unload(Cancel As Integer)
End
End Sub

Private Sub List1_Click()
Dim x, y, z
Dim AnyString, MyStr
z = Right(List1.Text, 3) ' Define string.
If z = "EXE" Then
    y = List1.Text
    x = Shell(y, vbNormalFocus)
Else
    y = "Explorer " & List1.Text
    x = Shell(y, vbNormalFocus)
End If
End Sub

Private Sub Form_Load()
  Command1.caption = "&Accept Files"
  Command2.caption = "Clear"
  Command3.caption = "End"
  Label1.caption = "The number of files that were " & "last dropped on the list box"
End Sub

'8. Go into the Project Properties dialog box and change the
'   Startup Object to Sub Main.

'9. Now run the project. Click on the Accept files command 
'   button. Now drag some files and folder on the list box. They will be disaplyed in the list box. If you click on a file or folder in the list box the folder or file will be opened.
 In this article I will carry on from last week when I showed
you how to search you computer for a specified program. 
This week I will show you how to allow the user to be able 
to drag a file or folder onto a list box or textbox and it 
will display the relative path and file name if you dragged 
a file. It will also tell you how many files you last 
dropped to the control on the form.
This is very useful, when you want a number of files, say to
check the integrity of the specified file. It also can be 
used for many other functions, including the path of where 
certain files are. This can be accomplished by using four

Windows API's. Which are:
DragAcceptFile
DragFinish
DragQueryFile
PeekMessage

If you would like any more detailed information then you can
contact me at my email address (steve@microweird.demon.co.uk)

Sample Project

1. Start a new standard EXE project in Visual Basic. 
   Form one is created by default

2. Add a normal module to the project, by clicking on the 
   Project menu and choosing insert module.

3. You will need to declare the following types, by typing 
   the following in to the beginning of the module

Type POINTAPI
x As Long
y As Long
End Type

Type MSG
hWnd As Long
message As Long
wParam As Long
lParam As Long
time As Long
pt As POINTAPI
End Type

'4. You now need to add the following Windows API calls to

' the module. Make sure that each API is on one line

Declare Sub DragAcceptFiles Lib "shell32.dll" (ByVal hWnd As Long, ByVal fAccept As Long)
Declare Sub DragFinish Lib "shell32.dll" (ByVal hDrop As Long)
Declare Function DragQueryFile Lib "shell32.dll" Alias "DragQueryFileA" (ByVal hDrop As Long, ByVal UINT As Long, ByVal lpStr As String, ByVal ch As Long) As Long
Declare Function PeekMessage Lib "user32" Alias "PeekMessageA" (lpMsg As MSG, ByVal hWnd As Long, ByVal wMsgFilterMin As Long, ByVal wMsgFilterMax As Long, ByVal wRemoveMsg As Long) As Long
Public Const PM_NOREMOVE = &H0
Public Const PM_NOYIELD = &H2
Public Const PM_REMOVE = &H1
Public Const WM_DROPFILES = &H233

'5. You will now need to add the following procedures to the

' module.

' This is the sub main procedure, that is called

' for any of the forms are loaded.

Sub Main()
' In order for this to function properly you should

' place of of your program execution code in

' the Sub Main(), Make sure you change the project

' startup to sub Main

Form1.Show
' This must be the last line! Nothing gets called

' after this

WatchForFiles
End Sub

Public Sub WatchForFiles()
' This subroutine watchs for all of your WM_DROPFILES

' messages

' Dim Variables

Dim FileDropMessage As MSG ' Msg Type
Dim fileDropped As Boolean ' True if Files where dropped
Dim hDrop As Long ' Pointer to the dropped file structure
Dim filename As String * 128 ' the dropped filename
Dim numOfDroppedFiles As Long ' the amount of dropped files
Dim curFile As Long ' the current file number
' loop to keep checking for files

' NOTE : Do any code you want to execute before this set

Do
' check for Dropped file messages

fileDropped = PeekMessage(FileDropMessage, 0, _
WM_DROPFILES, WM_DROPFILES, PM_REMOVE Or PM_NOYIELD)
If fileDropped Then
' Get the pointer to the dropped file structure

hDrop = FileDropMessage.wParam

' Get the toal number of files

numOfDroppedFiles = DragQueryFile(hDrop, True, _
filename, 127)

For curFile = 1 To numOfDroppedFiles
' Get the file name

ret% = DragQueryFile(hDrop, curFile - 1, filename, 127)
' at this pointer you can do what you want with the

' filename the filename will be a full qalified path

Form1.lblNumDropped = LTrim$(Str$(numOfDroppedFiles))
Form1.List1.AddItem filename
Next curFile

' We are now done with the structure, tell windows

' to discard it

DragFinish (hDrop)
End If
DoEvents
Loop
End Sub

'6. Open up form one. Draw the following 3 command buttons

1 list box 2 labels - one called "lblNumDropped"

'7. Now open up the code window for form1 and type the

following

Private Sub Command1_Click()
' You can turn the form's / controls ability

' to accept the files by passing the hWnd as

' the first parameter and True/False as the

' Second

If Command1.Caption = "&Accept Files" Then
' allow the application to accept files

DragAcceptFiles Form1.hWnd, True
Command1.Caption = "&Do Not Accept"
Else
DragAcceptFiles Form1.hWnd, False
Command1.Caption = "&Accept Files"
End If
End Sub

Private Sub Command2_Click()
' Clears the contents of the list box

List1.Clear
End Sub

Private Sub Command3_Click()
' End the program

End
End Sub

Private Sub Form_Unload(Cancel As Integer)
End
End Sub

Private Sub List1_Click()
Dim x, y, z
Dim AnyString, MyStr
z = Right(List1.Text, 3) ' Define string.
If z = "EXE" Then
y = List1.Text
x = Shell(y, vbNormalFocus)
Else
y = "Explorer " & List1.Text
x = Shell(y, vbNormalFocus)
End If
End Sub

Private Sub Form_Load()
Command1.caption = "&Accept Files"
Command2.caption = "Clear"
Command3.caption = "End"
Label1.caption = "The number of files that were " & "last dropped on the list box"
End Sub

'8. Go into the Project Properties dialog box and change the

' Startup Object to Sub Main.

'9. Now run the project. Click on the Accept files command

' button. Now drag some files and folder on the list box. They will be disaplyed in the list box. If you click on a file or folder in the list box the folder or file will be opened.

In this article I will carry on from last week when I showed
you how to search you computer for a specified program.
This week I will show you how to allow the user to be able
to drag a file or folder onto a list box or textbox and it
will display the relative path and file name if you dragged
a file. It will also tell you how many files you last
dropped to the control on the form.
This is very useful, when you want a number of files, say to
check the integrity of the specified file. It also can be
used for many other functions, including the path of where
certain files are. This can be accomplished by using four

Windows API's. Which are:
DragAcceptFile
DragFinish
DragQueryFile
PeekMessage

If you would like any more detailed information then you can
contact me at my email address (steve@microweird.demon.co.uk)

Sample Project

1. Start a new standard EXE project in Visual Basic.
Form one is created by default

2. Add a normal module to the project, by clicking on the
Project menu and choosing insert module.

3. You will need to declare the following types, by typing
the following in to the beginning of the module