Visual Basic

18-Jun-04 10:09

Earlier I asked the question about displaying the contents of a selected folder in a ListView. After Dave’s response and hours of searching books and the Internet I can’t seem to find anything about this.

What I’m looking for is something that will react in the same way that Windows Explorer does when the main window is set to ‘Thumbnails’; when a folder is opened in the TreeView, the main window displays all images as thumbnails.

How do I make this:
ListBox1.DataSource = Directory.GetFiles("C:\")
display the thumbnail images in the directory?

Does anybody have any idea how this can be accomplished?

Thanks
Brad

tanstaafl2819-Jun-04 10:10

19-Jun-04 10:10

I misunderstood what you were trying to do. Here's a thumbnail viewer you can download from this very site:

http://www.codeproject.com/csharp/thumbgenerator.asp

Brad Fackrell21-Jun-04 5:21

21-Jun-04 5:21

Thanks.

That looks great for making thumbnails. That’s not exactly what I’m looking for but it will come in handy latter on.

I’m actually trying to create an Explorer-Style Application. I’ve figured out how to create the application but what I can’t figure out how to do is set it to display thumbnail images of any image file that is located in the directory that is currently open in the TreeView.

I know it’s possible because, in Windows Explorer, when you click ‘Thumbnails’ under the ‘View’ option, thumbnail images are displayed.

Have you ever seen the code for this before?

Thanks
Brad

tanstaafl2821-Jun-04 8:31

21-Jun-04 8:31

I have not reached the level of experience necessary to directly answer your question, however, I've been looking into this as a learning exercise for myself. Perhaps in my thought processes, there will be a thread you can expand upon.

I have been looking for a way to programmatically evoke the thumbnail view, even if it had to be done by opening a specific folder path and making the setting changes via the built-in menu, but I am not seeing this option.

The System.Windows.Forms.OpenFileDialog does allow you to filter specific file types, so you can limit your view to just the image files if you wanted. The question is where is the option to view those files as thumbnails?

If it isn't a built-in class, I am thinking it should be possible to create a class to do this. When I was learning VBA, I would simply run the macro recorder and manually do what it was I wanted to code and then edit the recorded code to fit my specifications.

I am confident that there is a way to do this, it is just that we have not yet found the right set of method(s) to make it happen.

Still coaxing software out of the can after all these years...

Brad Fackrell21-Jun-04 8:39

21-Jun-04 8:39

Thanks again Smile | :)

Any input that you can provide will be helpful.

When I figure this out, assuming that I have an ounce of life left in me Dead | X|

, I will post the result for everybody. I’ve been doing a lot of research and there just doesn’t seem to be any information about this that can be found.

Thanks
Brad

tanstaafl2821-Jun-04 9:07

21-Jun-04 9:07

I did find some interesting stuff, but I don't know how related it is to exactly what you are looking to do. You may find that ASP has as much to do with the solution as VB.NET. You may be able to reverse engineer something like this to get what you need:

Dim sPath, ot, oFSO, sFolderName, i, iNode<br />
	<br />
	<br />
	' Get Folder Path and Folder Name.<br />
	<br />
	sPath = Server.MapPath(Request.ServerVariables("Path_INFO"))<br />
	Do Until Right(sPath, 1) = "\"<br />
		sPath = Left(sPath, Len(sPath) - 1)<br />
	Loop<br />
	i = Len(sPath) - 1<br />
	Do Until Mid(sPath, i, 1) = "\"<br />
		sFolderName = Mid(sPath, i, Len(sPath) - i)<br />
		i = i - 1<br />
	Loop<br />
	' You can set path and folder name like this:<br />
	' sPath = "C:\Inetpub\wwwroot\obout\treeview\AspTreeView\"<br />
	' sFolderName = "AspTreeView"<br />
	<br />
	' Create objects.<br />
	<br />
	Set oFSO = CreateObject("Scripting.FileSystemObject")<br />
	Set ot = Server.CreateObject("obout_aspTreeview_Pro.tree")<br />
	<br />
	' Populate first node manually. In Classic first node is "root".<br />
	ot.Add "", "root", " 0, 0, 128, 1)">" & sFolderName & "", True, "book.gif" <br />
	<br />
	' Show folders and files.<br />
	Call AddFolder(sPath, "../" & Escape(sFolderName), "root")<br />
	<br />
	' Write treeview to page.<br />
	Response.Write ot.HTML<br />
	Set ot = Nothing <br />
	Set oFSO = Nothing<br />
<br />
<br />
	<br />
Function AddFolder(pth, dpt, parentID)<br />
	Dim oF, oFolder, oFile, oSubFolder, oItem<br />
<br />
	Set oFolder = oFSO.GetFolder(pth)<br />
	Set oSubFolder = oFolder.SubFolders<br />
	Set oFile = oFolder.Files<br />
	<br />
	' Display Subfolders.<br />
	For Each oItem In oSubFolder <br />
		iNode = iNode + 1<br />
		ot.Add parentID, "z" & iNode, "<span onclick='ob_os(this)'> " & oItem.Name & "</span>"<br />
		Call AddFolder(oItem.Path, dpt & "/" & Escape(oItem.Name), "z" & iNode)<br />
	Next<br />
	<br />
	' Display Files.<br />
	For Each oF In oFile<br />
		iNode = iNode + 1<br />
		ot.Add parentID, "z" & iNode, " <a href=" & dpt & "/" & Escape(oF.Name) & ">" & oF.Name & "</a>", , "page.gif" <br />
	Next<br />
End Function<br />

http://www.obout.com/obout/treeview/asptreeview/explorer.asp

Some other promising links:

Explorer shell extension software downloads

http://www.brightdownloads.com/software/6531.htm

Still coaxing software out of the can after all these years...

tanstaafl2821-Jun-04 9:14

21-Jun-04 9:14

I found a link here that might be helpful:

http://www.codeproject.com/books/1930110286_10.asp

Still coaxing software out of the can after all these years...

Brad Fackrell21-Jun-04 9:43

21-Jun-04 9:43

Thanks again!

I’m jumping back-and-fourth right but I’ll be back to this TreeView thing latter. It looks like the article that you suggested just might do the trick! Big Grin | :-D

Thanks
Brad

tanstaafl2821-Jun-04 12:20

21-Jun-04 12:20

I happen to have the book entitled 101 Visual Basic .NET Applications and application # 35 is "Create an Explorer-Style Application," however, it contains everything except a thumbnail view option.

All 101 code samples are available for download under "Companion Content" at the following URL:

http://www.microsoft.com/mspress/books/companion/6510.asp

I also poked around in the Object Browser and found this:

Image.GetThumbnailImage Method

<br />
Public Function GetThumbnailImage( _<br />
   ByVal thumbWidth As Integer, _<br />
   ByVal thumbHeight As Integer, _<br />
   ByVal callback As Image.GetThumbnailImageAbort, _<br />
) As Image<br />

Still coaxing software out of the can after all these years...

Brad Fackrell21-Jun-04 13:00

21-Jun-04 13:00

tanstaafl28 wrote:
I happen to have the book entitled 101 Visual Basic .NET Applications

I actually just bought that same book over the weekend. The Explorer-Style Application is exactly what caught my eye. But, as you also know, it doesn’t describe the one little thing that I’m looking for...I guess that they can’t cover everything. Roll eyes | :rolleyes:

It is a great book though. I’ve looked at it several times in the book store so I finally decided to buy it.

tanstaafl2822-Jun-04 4:06

22-Jun-04 4:06

Brad, I have another idea for you. It was one of those things where I wasn't looking for anything in particular, but I was thumbing through my copy of Windows XP Annoyances when I came to a section called: "Turn File Icons into Thumbnail Previews." The instructions are straightforward:

Open Explorer, and locate any folder that contains at least one graphic image file (.jpg, gif, or bmp). Select Thumbnails from the View menu (This option may not be available unless you have Internet Explorer integration disabled). Select one of the other view modes (such as details or Large icons) to resture the display to normal.
If you've configured Explorer to display hidden files, you'll notice a new hidden file thumbs.db (which contains the thumbnail data), in any folder you view. As long as this file is present, the folder's view will always be set to Thumbnails. If you delete the file, and then re-open the folder, it should be back to the standard details or large icons view.

Windows XP Annoyances pp 147-48.

Everything but the last part works in 2k (I have view hidden files and folders and I don't see that thumbs.db anywhere), so all you need to do is find a way to programmatically mimic this and you'll be good to go.

There is also some mention of looking in the registry for HKEY_CLASSES_ROOT\Paint.Pictures\
DefaultIcon and changing the default value to %1. This seems to apply to bitmaps only, but there has to be an iconic reference in the registry for other graphical files as well.

I was thinking that there is a way to filter file views by specific types in VB.NET, if this can be combined with the listview/treeview commands and then the above thumbnail info included, you'd be good to go.

Oh, and Annoyances.org is the Windows Annoyances website, lots of good references and ideas on how to figure out built-in Windows functions and how to access them there.

Still coaxing software out of the can after all these years...

Brad Fackrell22-Jun-04 4:34

22-Jun-04 4:34

tanstaafl28 wrote:
Everything but the last part works in 2k

I get the same result that you get.

tanstaafl28 wrote:
so all you need to do is find a way to programmatically mimic this

Do you mean that I need to find a way to create the thumbs.db?

If I understand you, it seems that you think that the key is to generate (on the fly) code that will make thumb nails and display them in place of the default thumbnail image. Is that right?

Brad

tanstaafl2822-Jun-04 9:25

22-Jun-04 9:25

If I understand you, it seems that you think that the key is to generate (on the fly) code that will make thumb nails and display them in place of the default thumbnail image. Is that right?

I'm thinking this might be a solution you can try. The idea is that VB.NET is powerful enough to do just about anything Windows can do, so it should be possible to create a custom Windows form that utilizes the built-in functions of Windows to perform the desired task. Its the "don't try to reinvent the wheel" approach. The problem is that for some reason, the thumbnail option seems to be missing from the view options. All the other ones are there.

What keeps going through my mind is a simple "Image Browser" which would include a dynamic array "stack" that would fill up with all the image file types in that folder and the user would "view" them one at a time by using a "Previous" and "Next" command button and a picture window. Of course this starts to sound just like IrfanView, which is someone else's idea of an image browser.

It might be easier still if you could skip the listview/treeview form all together and just call up the actual explorer dialog that does have the option to view as thumbnails. If that is possible.

Still coaxing software out of the can after all these years...

Brad Fackrell22-Jun-04 9:37

22-Jun-04 9:37

tanstaafl28 wrote:
It might be easier still if you could skip the listview/treeview form all together and just call up the actual explorer dialog

That might be the route to take for now. I can perfect it latter on. Do you know if it is possible to run explorer from within another application? Not open independently but as part of the application that I’m creating. Hmmm...maybe I'm getting a bit carried away now. Roll eyes | :rolleyes:

When I get home tonight, I'm going to see if I can generate the thumbs.db on an XP machine. Maybe the key lies within that little guy.;)

Thanks for all of your help! Smile | :)

tanstaafl2822-Jun-04 10:42

22-Jun-04 10:42

Hey no problem Brad, I learned all sorts of things by just tossing out ideas. The law of averages being what it is, there's a good possibility that one of them will lead to something you can use.

Running Explorer from another application, hmmm...it depends greatly on the application. I can think of about a half dozen programs that use some version of scripting or VBA to provide customization options.

Better stick to one problem at a time. Crack this nut first.

Still coaxing software out of the can after all these years...

Trying an Excel Interop

tanstaafl2818-Jun-04 7:57

18-Jun-04 7:57

I'm following along with this book and it says to add a reference library to Excel. In the book it has Excel 10, but I have Excel 11, which I suspect is irrelevant, but when I try to add a variable based upon Excel.Application, Visual Studio acts as if I haven't added the reference. Squiggly blue line under Excel.Application. The code below is
the click event where the Excel.Application is called:

Private Sub btnCalculate_Click(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles btnCalculate.Click
Dim xlApp As Excel.Application
Dim LoanPayment As Single
xlApp = CType(CreateObject("Excel.Application"), Excel.Application)
LoanPayment = xlApp.WorksheetFunction.Pmt _
(txtInterest.Text / 12, txtMonths.Text, txtPrincipal.Text)
MsgBox("The monthly payment is " & _
Format(Abs(LoanPayment), "$#.##"), , "Mortgage")
xlApp.Quit()
End Sub
End Class

Not only do I have Office 2003, but I have Visual Studio Tools for the Microsoft Office System 2003 installed. Why isn't my reference working?

Still coaxing software out of the can after all these years...

tanstaafl2818-Jun-04 8:18

18-Jun-04 8:18

I was able to use the book as a reference, but what I had to do to get this interop to work was a bit different:

Private Sub btnCalculate_Click(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles btnCalculate.Click
1:
Dim xlApp As Microsoft.Office.Interop.Excel.Application

Dim LoanPayment As Single
xlApp = CType(CreateObject("Excel.Application"), _
Microsoft.Office.Interop.Excel.Application)
LoanPayment = xlApp.WorksheetFunction.Pmt _
(txtInterest.Text / 12, txtMonths.Text, txtPrincipal.Text)

MsgBox("The Monthly Payment is " & _
Format(Abs(LoanPayment), "$#.##"), , "Mortgage")
xlApp.Quit()

End Sub
End Class

Why did I have to specify more precisely than the book suggested?

Dave Kreskowiak18-Jun-04 8:34

Dave Kreskowiak

18-Jun-04 8:34

Try putting this at the top of your code:

Imports Microsoft.Office.Interop

You should then be able to make it look just like the book.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

tanstaafl2818-Jun-04 9:05

18-Jun-04 9:05

Thanks Dave.

The book was set up for use with Excel 2002, is there that big of a difference between Excel 10 and Excel 11? Smile | :)

Still coaxing software out of the can after all these years...

Dave Kreskowiak18-Jun-04 9:06

Dave Kreskowiak

18-Jun-04 9:06

Yes, there is. Starting with Office XP, Microsoft is putting out Primary Interop Assemblies that allow for easier integration with .NET Framework apps.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

tanstaafl2818-Jun-04 9:09