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Posted 25 Jul 2007

Create Open File Dialog for Windows Mobile 6 (SmartPhone) Devices

, 25 Jul 2007
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Create an Open File Dialog for a Windows Mobile 6 (SmartPhone) devices.

Introduction

While working on the project of converting and upgrading Siccolo for Windows Mobile 5 to Siccolo for Windows Mobile 6 for Smartphones, I realized that Windows Mobile 6 for Smartphone edition is missing OpenFilDlg and SaveFileAsDlg controls. By default, a Smartphone does not include a File Explorer application and there are no common file dialog boxes available to the developer.

Some of the features of Siccolo include ability to browse and select SQL Script on mobile device, and be able to save SQL Script in a given folder on the mobile device.
This article shows how to create a form to allow select file for opening, or to "Save File As":

Code

Now, the code part. In my case, I wanted to create a form that:

  • Looks and works like standard file explorer in Windows Mobile 6
  • Allows to switch between "Open File" and "Save File As" dialog mode - allows to select a file to open, or to select a folder and enter a file name for saving
  • Exposes SelectedFileName as a property
  • Allows to "filter" files to display

To display folders and files on the mobile device, I'm using the TreeView control. To allow one form to behave as "Open File Dialog" and "Save File As Dialog", I added text box (hidden/shown during run-time based on selection):

Public Enum DialogMode As Integer
     OpenFile = 0
     SaveFileAs = 1
 End Enum
 Private m_DialogMode As DialogMode = DialogMode.OpenFile
 Public Property Mode() As DialogMode
     Get
         Return m_DialogMode
     End Get
     Set(ByVal value As DialogMode)
         m_DialogMode = value

         If m_DialogMode = DialogMode.SaveFileAs Then
             txtFileName.Visible = True
             lblFileName.Visible = True
             trwFileExplorer.Height = _
         trwFileExplorer.Height - txtFileName.Height - 10
         End If
     End Set
 End Property

and to display such form:

 ...
 ...
Dim dlgOpenFile As New frmOpenFileDialogSP
dlgOpenFile.Filter = "*.sql"
dlgOpenFile.Mode = frmOpenFileDialogSP.DialogMode.OpenFile

If dlgOpenFile.ShowDialog() = Windows.Forms.DialogResult.OK Then
 ...
 ...

In the TreeView, I wanted to display just "one level", and as soon as the user selects a folder, TreeView will display contents (sub-folders and files) of the selected folder:

In order to populate TreeView with sub folders and files for a given folder:

Private Sub AddSubFolders(ByVal ParentPath As String)
     Try

         Dim ParentFolder As New DirectoryInfo(stripExtraSlash(ParentPath))

         'loop in directories
         Dim DirInfoComparer As DirectoryInfoComparer =
                     New DirectoryInfoComparer()
         Dim DirList() As DirectoryInfo = ParentFolder.GetDirectories()
         Array.Sort(DirList, DirInfoComparer)

         Dim dirInfo As DirectoryInfo

         For Each dirInfo In DirList 'ParentFolder.GetDirectories()
             Dim DirectoryNode As New TreeNode
             DirectoryNode.Text = dirInfo.Name ' name of file or dir
             DirectoryNode.Tag = dirInfo.FullName
             DirectoryNode.ImageIndex = 0 'folder
             trwFileExplorer.Nodes.Add(DirectoryNode)
         Next

         'loop in files:
         Dim FileInfoComparer As FileInfoComparer = New FileInfoComparer()

         If m_Filter = "" Then m_Filter = "*.*"
         Dim FileList() As FileInfo = ParentFolder.GetFiles(m_Filter)
         Array.Sort(FileList, FileInfoComparer)

         Dim fileInfo As FileInfo
         Dim AddFile As Boolean = True

         For Each fileInfo In FileList   'ParentFolder.GetFiles()
             Dim FileNode As New TreeNode
             FileNode.Text = fileInfo.Name
             FileNode.Tag = fileInfo.FullName
             FileNode.ImageIndex = 1 'file
             FileNode.SelectedImageIndex = 1 'file
             trwFileExplorer.Nodes.Add(FileNode)
         Next

     Catch ex_add_subfolder As Exception
         ' handle error here....
     End Try
 End Sub

In the above code:

  1. First, get a folder we're in: Dim ParentFolder As New DirectoryInfo(stripExtraSlash(ParentPath)), where stripExtraSlash() function :

    Private Function stripExtraSlash(ByVal str As String) As String
         ' —-strip away the extra "\" for
         ' subdirectories. e.g. \\My documents
         Dim path As String = str
         If path.Length > 1 And (Mid(path, 1, 1) = "\") Then
             path = Mid(path, 2, path.Length - 1)
         End If
    
         Return path
     End Function
    

  2. Then, get sub-folders, using ParentFolder.GetDirectories(). But because I wanted to present a list of folders and files sorted, I had to add "custom" comparer for sorting:

     ...
    <code>Dim DirInfoComparer As DirectoryInfoComparer =
                     New DirectoryInfoComparer()
    Dim DirList() As DirectoryInfo = ParentFolder.GetDirectories()
    Array.Sort(DirList, DirInfoComparer)
     ...
    

    where DirectoryInfoComparer() and FileInfoComparer():

    Imports System.IO
    
    Public Class DirectoryInfoComparer _
            Implements System.Collections.IComparer
    
        Public Function Compare(ByVal objDirInfo1 As Object, _
                ByVal objDirInfo2 As Object) As Integer _
                Implements IComparer.Compare
            Dim DirInfo1 As System.IO.DirectoryInfo = _
                CType(objDirInfo1, System.IO.DirectoryInfo)
            Dim DirInfo2 As System.IO.DirectoryInfo = _
                CType(objDirInfo2, System.IO.DirectoryInfo)
    
            Return String.Compare(DirInfo1.Name, DirInfo2.Name, True)
        End Function
    End Class
    
    Public Class FileInfoComparer   Implements System.Collections.IComparer
        Public Function Compare(ByVal objFileInfo1 As Object, _
                ByVal objFileInfo2 As Object) As Integer _
                Implements IComparer.Compare
            Dim FileInfo1 As System.IO.FileInfo = _
                CType(objFileInfo1, System.IO.FileInfo)
            Dim FileInfo2 As System.IO.FileInfo = _
                CType(objFileInfo2, System.IO.FileInfo)
    
            Return String.Compare(FileInfo1.Name, FileInfo2.Name, True)
        End Function
    End Class

  3. Once folders are "sorted" in a better way, we can add them to the TreeView:

     ...
    For Each dirInfo In DirList 'ParentFolder.GetDirectories()
                 Dim DirectoryNode As New TreeNode
                 DirectoryNode.Text = dirInfo.Name ' name of file or dir
                 DirectoryNode.Tag = dirInfo.FullName
                 DirectoryNode.ImageIndex = 0 'folder
                 trwFileExplorer.Nodes.Add(DirectoryNode)
    Next
    
     ...
    

Notice, as a folder node is added to TreeView, node tag contains full name of a direcory being added.
And files are the same way - get them with ParentFolder.GetFiles(), sort them using FileInfoComparer(), add them to TreeView using Nodes.Add(). We can also provide "filtering" with ParentFolder.GetFiles(searchPattern).

When the user selectes a folder (using "enter" key on smartphone), TreeView is populated with contents of that folder:

Private Sub frmOpenFileDialogSP_KeyDown(ByVal sender As System.Object, _
     ByVal e As System.Windows.Forms.KeyEventArgs) _
         Handles MyBase.KeyDown
     ...
     If (e.KeyCode = System.Windows.Forms.Keys.Enter) Then
         'Enter:
         'do we have file selected?
         If trwFileExplorer.SelectedNode Is Nothing Then
             Exit Sub
         End If

         If trwFileExplorer.SelectedNode.ImageIndex <> 1 Then
             <code>Dim Path As String = _
                     System.IO.Path.Combine(trwFileExplorer.Tag, _
             trwFileExplorer.SelectedNode.FullPath)
             trwFileExplorer.BeginUpdate()
             'delete nodes:
             trwFileExplorer.Nodes.Clear()
             'selected is folder - open it!
             AddTopFolder(Path)
             'done
             trwFileExplorer.EndUpdate()
             Exit Sub
         End If

     ...
     ...

     End If

     ...
     ...
 End Sub

Where AddTopFolder() function:

Private Sub AddTopFolder(ByVal InitialPath As String)

     Dim strPath As String = IIf(InitialPath = "", "\", InitialPath)

     'check if path given is valid:
     Try
         Dim TopFolder As New DirectoryInfo(stripExtraSlash(strPath))

         ChangeTopFolder(TopFolder)

         mnuUp.Enabled = Not (TopFolder.Parent Is Nothing)

     Catch ex As Exception

         MessageBox.Show("Invalid Path [" & InitialPath & "]" & vbCrLf & _
                        "-----------------------------------" & vbCrLf & _
                        ex.Message & vbCrLf & _
                        "-----------------------------------", _
                        "Siccolo SP", _
                        MessageBoxButtons.OK, _
                        MessageBoxIcon.Exclamation, _
                 MessageBoxDefaultButton.Button1)

         Me.DialogResult = Windows.Forms.DialogResult.Cancel
         Me.Close()

     End Try


     'Dim newNode As Windows.Forms.TreeNode = New TreeNode
     'newNode = trwFileExplorer.Nodes.Add(strNode)
     'newNode.Tag = strNode
     '************************************************************
     'add sub folders, under root folder:
     AddSubFolders(strPath)
     '************************************************************
 End Sub

And ChangeTopFolder():

Private Sub ChangeTopFolder(ByVal Folder As DirectoryInfo)
    lblPath.Text = Folder.Name
    <code>trwFileExplorer.Tag = Folder.FullName
End Sub

So, anytime the ParentFolder is changed - TreeView keeps directory name in Tag property - to get the full path of a selected folder in TreeView, we just need to combine Path.Combine(trwFileExplorer.Tag, trwFileExplorer.SelectedNode.FullPath).
Then, we just need to allow the user to go up one level (as in standard Windows Mobile File Explorer):

Private Sub mnuUp_Click(ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles mnuUp.Click
    'can we go Up?!:
    Try
        Dim Path As String = trwFileExplorer.Tag
        Dim ParentFolder As DirectoryInfo = New DirectoryInfo(Path)
        If ParentFolder.Parent Is Nothing Then Exit Sub

        Path = ParentFolder.Parent.FullName

        trwFileExplorer.BeginUpdate()
        'delete nodes:
        trwFileExplorer.Nodes.Clear()
        'selected is folder - open it!
        AddTopFolder(Path)
        'done
        trwFileExplorer.EndUpdate()

    Catch ex_go_up As Exception
    End Try
End Sub

To "go up" - because TreeView.Tag property contains the full directory path of the current folder, based on that we create New DirectoryInfo(Path), and by referencing ParentFolder.Parent, we get full the directory path of "up" folder.

To handle "Save File As":

  • txtFileName is shown:

     ...
    If m_DialogMode = DialogMode.SaveFileAs Then
                 <codetxtFileName.Visible = True
                 lblFileName.Visible = True
                 trwFileExplorer.Height = _
             trwFileExplorer.Height - txtFileName.Height - 10
    End If
     ...
    

  • and, to allow user "jump" from TreeView to text box txtFileName, to enter a "Save File As" file name:

    Private Sub frmOpenFileDialogSP_KeyDown(ByVal sender As System.Object, _
            ByVal e As System.Windows.Forms.KeyEventArgs) _
                        Handles MyBase.KeyDown
            <code>If (e.KeyCode = System.Windows.Forms.Keys.Left) Then
                'Left
                If m_DialogMode = DialogMode.SaveFileAs Then
                    'move focus to text box
                    txtFileName.Focus()
                End If
            End If
    
            If (e.KeyCode = System.Windows.Forms.Keys.Right) Then
                'right
                If m_DialogMode = DialogMode.SaveFileAs Then
                    'move focus to text box
                    txtFileName.Focus()
                End If
            End If
        
            If (e.KeyCode = System.Windows.Forms.Keys.Enter) Then
                'Enter:
                'do we have file selected?
                If trwFileExplorer.SelectedNode Is Nothing Then
                    Exit Sub
                End If
    
                If trwFileExplorer.SelectedNode.ImageIndex <> 1 Then
                    Dim Path As String = _
                System.IO.Path.Combine(trwFileExplorer.Tag, _
                    trwFileExplorer.SelectedNode.FullPath)
                    trwFileExplorer.BeginUpdate()
                    'delete nodes:
                    trwFileExplorer.Nodes.Clear()
                    'selected is folder - open it!
                    AddTopFolder(Path)
                    'done
                    trwFileExplorer.EndUpdate()
                    Exit Sub
                End If
    
                'else - selected is file - exit
                If m_DialogMode = DialogMode.OpenFile Then
                    'set properties:
                    m_FullPath = trwFileExplorer.Tag
                    m_SelectedFileName = trwFileExplorer.SelectedNode.Text
                    m_SelectedFullFileName = System.IO.Path.Combine_
                        (m_FullPath, m_SelectedFileName)
    
                    Me.DialogResult = Windows.Forms.DialogResult.OK
                    Me.Close()
    
                Else
                    'move focus to text box
                    txtFileName.Focus()
                End If
            End If
    
    End Sub

And finally, when the user "clicks" the enter key:

Private Sub frmOpenFileDialogSP_KeyDown(ByVal sender As System.Object, _
     ByVal e As System.Windows.Forms.KeyEventArgs) Handles MyBase.KeyDown
 ...

         If m_DialogMode = DialogMode.OpenFile Then
             'set properties:
             m_FullPath = trwFileExplorer.Tag
             m_SelectedFileName = trwFileExplorer.SelectedNode.Text
             m_SelectedFullFileName = System.IO.Path.Combine_
                 (m_FullPath, m_SelectedFileName)

             Me.DialogResult = Windows.Forms.DialogResult.OK
             Me.Close()

         Else
             'move focus to text box
             txtFileName.Focus()
         End If
 ...
 end sub

 Private Sub txtFileName_KeyDown(ByVal sender As Object, _
         ByVal e As System.Windows.Forms.KeyEventArgs) _
     Handles txtFileName.KeyDown
     If (e.KeyCode = System.Windows.Forms.Keys.Enter) Then
         If m_DialogMode = DialogMode.SaveFileAs Then
             'set properties:
             m_FullPath = trwFileExplorer.Tag
             m_SelectedFileName = txtFileName.Text
             m_SelectedFullFileName = System.IO.Path.Combine_
                 (m_FullPath, m_SelectedFileName)

             Me.DialogResult = Windows.Forms.DialogResult.OK
             Me.Close()
         End If
     End If
 End Sub

The result:

More on this subject

Points of Interest

If you would like to read more on this story - please take a look at Siccolo - Free Mobile Management Tool For SQL Server and more articles at Siccolo Articles.

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

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About the Author

aleksisa
United States United States
No Biography provided

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Comments and Discussions

 
GeneralMy vote of 1 Pin
bjren9913-Jan-10 18:34
memberbjren9913-Jan-10 18:34 
QuestionDownload available ? Pin
HaydenGill10-Sep-08 21:15
memberHaydenGill10-Sep-08 21:15 
GeneralExcellent Pin
Syed M Hussain27-Jul-07 11:25
memberSyed M Hussain27-Jul-07 11:25 
GeneralRe: Excellent Pin
aleksisa27-Jul-07 11:32
memberaleksisa27-Jul-07 11:32 
Thank you. check out Siccolo at http://wwww.siccolo.com

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