Various ways to display multiple photographs
You can use an array of PictureBox controls to display multiple photographs or other images. The sample below subclasses the PictureBox control and puts an array of them on a form. You need to change the PixPath to point to a directory with your digital photos.
(For an easy way to run the sample, see Use temporary projects in Visual Studio)
For years, I’ve had the capability to display an array of images on my Fox custom photo viewer application. When I ran the initial version of the code below, it was painfully slow. Even changing it to use dynamic thumbnails was much slower than the Fox version. Upon further investigation, the Fox version uses a separate related table of thumbnails that have already been generated.
You can use Spy++ from Visual studio to see that the PictureBox indeed has its own hWnd, and thus is a Windows Window.
An even faster alternative is to subdivide the Form’s hWnd into rectangles and draw the images in each rect. (next blog post)
The code also shows how to use lots of memory by using the ImageLocation property directly for the photo, or to create a thumbnail first, which is much faster and memory efficient.
I have all my 25,000 digital photos in a table (the size of which is about 2 photos), which can be queried easily using the VFP OleDB driver.
See also Sharing Digital Pictures of your friend's
Imports System.Data.OleDb
Module Myvars
Public dt As New DataTable
Public fUseDBF As Boolean = False
Public fPixPathPrefix As String = "d:\pictures\"
Public fUseLotsOfMemory As Boolean = False
End Module
Public Class Form1
Dim xpix As Integer = 8
Dim ypix As Integer = 8
Dim aPic(xpix, ypix) As PictureBox
'Change pixPath to point to a dir tree with many pictures
Dim PixPath As String = "d:\pictures\2006\08"
'Dim PixPath As String = "c:\windows\help\tours\htmltour"
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'This code puts an array (xpix by ypix) of PictureBoxes on form
Dim nRow, nCol As Integer
If fUseDBF Then
Dim da As New OleDb.OleDbDataAdapter("Select 'd:\pictures\'+fullname from mypix where 'tyler'$lower(notes) and '.JPG'$fullname", "Provider=VFPOLEDB.1;Data Source=d:\pictures\mypix.dbf")
da.Fill(dt)
Else
dt.Columns.Add(New DataColumn("path", GetType(String)))
For Each sFile As String In My.Computer.FileSystem.GetFiles(PixPath, FileIO.SearchOption.SearchAllSubDirectories, "*.jpg")
dt.Rows.Add(sFile)
Next
End If
Me.Text = dt.Rows.Count.ToString
Me.WindowState = FormWindowState.Maximized
For nCol = 0 To ypix - 1
For nRow = 0 To xpix - 1
Dim xx As Integer
xx = Me.Width / xpix.ToString
aPic(nRow, nCol) = New MyPictureBox '(Int(Me.Width / xpix), Int(Me.Height / ypix))
With aPic(nRow, nCol)
.Visible = True
.Height = Me.Height / ypix
.Width = Me.Width / xpix
.Top = nCol * .Height
.Left = nRow * .Width
.SizeMode = PictureBoxSizeMode.StretchImage
.Tag = nCol * ypix + nRow ' store the index in the tag
Me.Controls.Add(aPic(nRow, nCol)) ' add the control to the form
End With
Next
Next
End Sub
End Class
Class MyPictureBox
Inherits PictureBox
Private Sub MyPictureBox_MouseEnter(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.MouseEnter
If fUseLotsOfMemory Then
Me.FindForm.Text = Me.ImageLocation
Else
Me.FindForm.Text = dt.Rows(Me.Tag).Item(0).ToString.Trim
End If
End Sub
Private Sub MyPictureBox_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles Me.Paint
Dim nIndex As Integer = Me.Tag
If nIndex < dt.Rows.Count Then
If fUseLotsOfMemory Then ' GDI+ uses LOTS of memory!
If Me.ImageLocation Is Nothing Then
Me.ImageLocation = dt.Rows(nIndex).Item(0).ToString.Trim
End If
Else
If Me.Image Is Nothing Then ' use much less memory with dynamically created thumbnails
Dim imgBig As Image = New Bitmap(dt.Rows(nIndex).Item(0).ToString.Trim)
Me.Image = imgBig.GetThumbnailImage(Me.Width, Me.Height, Nothing, Nothing)
imgBig.Dispose() ' release the memory
End If
End If
End If
End Sub
End Class