I am trying to convert the regular sized images in a directory to
thumbnails and then display the thumbnails in a datalist. My code
below is displaying the first image and nothing else after it. What
do I have to do to have the thumbnails displayed in my datalist?
Thanks.
Dim strFile As String
Dim pics As ArrayList = New ArrayList
' Get image folder path on server - use "\" string if root
Dim strServerPath As String = Server.MapPath( "photos\")
For Each strFile In System.IO.Direc tory.GetFiles(s trServerPath,
"*.jpg")
' Get the regular sized image
Dim FullSizeImg As System.Drawing. Image
FullSizeImg = System.Drawing. Image.FromFile( strFile)
' Create the delegate
Dim dummyCallBack As System.Drawing. Image.GetThumbn ailImageAbort
dummyCallBack = New
System.Drawing. Image.GetThumbn ailImageAbort(A ddressOf
ThumbnailCallba ck)
' Create the thumbnail
Dim ThumbNailImg As System.Drawing. Image
ThumbNailImg = FullSizeImg.Get ThumbnailImage( 160, 120,
dummyCallBack, IntPtr.Zero)
ThumbNailImg.Sa ve(Response.Out putStream,
System.Drawing. Imaging.ImageFo rmat.Jpeg)
pics.Add(ThumbN ailImg)
Next
DataList1.DataS ource = pics
DataList1.DataB ind() 3 1010
Hi John
First, in the item template of the datalist you need an image control
Second, the image control needs a url (either src= or imageurl=, depending on whether it's a server control)
Third, you can do the url the easy way or the harder-but-cooler way
Easier way: Don't store your thumbnails in the array, instead write them to disk with temp names and store just the names in the array, then bind the source url to those names and you're off
Harder way: Keep your images in the arraylist, but now you need a url that returns each image from memory. Consider GetImage.aspx, which returns a byte stream the browser will interpret as an image, with something like this in PageLoad
Dim bmp As Image = New Bitmap(Server.M apPath("images\ myfile.jpg")
Dim thumb as image = bmp.GetThumbnai lImage, etc
Response.Conten tType = "image/jpeg
bmp.Save(Respon se.OutputStream , Imaging.ImageFo rmat.Jpeg
Now you bind the source url to GetImage.aspx and the thumbnail is fed from memory rather than disk
Finally, in my example GetImage returns the *same* image each time, so if your directory has 30 images you'd get the same one each time...not good. A few ways to go about it, buy maybe the easiest is that you build your arraylist with just the file names, pass the file name to GetImage.aspx in a query string, and let GetImage convert it to a thumbnail and stream it back
hth
Bil
P.S. If you're serious about it, there's a great discussion in Dino Esposito's book, Programming Microsoft ASP.NET
----- John wrote: ----
I am trying to convert the regular sized images in a directory t
thumbnails and then display the thumbnails in a datalist. My cod
below is displaying the first image and nothing else after it. Wha
do I have to do to have the thumbnails displayed in my datalist?
Thanks
Dim strFile As Strin
Dim pics As ArrayList = New ArrayLis
' Get image folder path on server - use "\" string if roo
Dim strServerPath As String = Server.MapPath( "photos\"
For Each strFile In System.IO.Direc tory.GetFiles(s trServerPath
"*.jpg"
' Get the regular sized imag
Dim FullSizeImg As System.Drawing. Imag
FullSizeImg = System.Drawing. Image.FromFile( strFile
' Create the delegat
Dim dummyCallBack As System.Drawing. Image.GetThumbn ailImageAbor
dummyCallBack = Ne
System.Drawing. Image.GetThumbn ailImageAbort(A ddressO
ThumbnailCallba ck
' Create the thumbnai
Dim ThumbNailImg As System.Drawing. Imag
ThumbNailImg = FullSizeImg.Get ThumbnailImage( 160, 120
dummyCallBack, IntPtr.Zero
ThumbNailImg.Sa ve(Response.Out putStream
System.Drawing. Imaging.ImageFo rmat.Jpeg
pics.Add(ThumbN ailImg
Nex
DataList1.DataS ource = pic
DataList1.DataB ind(
Thanks Bill. That was what I needed.
Bill Borg <an*******@disc ussions.microso ft.com> wrote in message news:<0F******* *************** ************@mi crosoft.com>... Hi John,
First, in the item template of the datalist you need an image control.
Second, the image control needs a url (either src= or imageurl=, depending on whether it's a server control).
Third, you can do the url the easy way or the harder-but-cooler way.
Easier way: Don't store your thumbnails in the array, instead write them to disk with temp names and store just the names in the array, then bind the source url to those names and you're off.
Harder way: Keep your images in the arraylist, but now you need a url that returns each image from memory. Consider GetImage.aspx, which returns a byte stream the browser will interpret as an image, with something like this in PageLoad:
Dim bmp As Image = New Bitmap(Server.M apPath("images\ myfile.jpg")) Dim thumb as image = bmp.GetThumbnai lImage, etc. Response.Conten tType = "image/jpeg" bmp.Save(Respon se.OutputStream , Imaging.ImageFo rmat.Jpeg)
Now you bind the source url to GetImage.aspx and the thumbnail is fed from memory rather than disk.
Finally, in my example GetImage returns the *same* image each time, so if your directory has 30 images you'd get the same one each time...not good. A few ways to go about it, buy maybe the easiest is that you build your arraylist with just the file names, pass the file name to GetImage.aspx in a query string, and let GetImage convert it to a thumbnail and stream it back.
hth,
Bill
P.S. If you're serious about it, there's a great discussion in Dino Esposito's book, Programming Microsoft ASP.NET.
----- John wrote: -----
I am trying to convert the regular sized images in a directory to thumbnails and then display the thumbnails in a datalist. My code below is displaying the first image and nothing else after it. What do I have to do to have the thumbnails displayed in my datalist? Thanks.
Dim strFile As String Dim pics As ArrayList = New ArrayList
' Get image folder path on server - use "\" string if root Dim strServerPath As String = Server.MapPath( "photos\")
For Each strFile In System.IO.Direc tory.GetFiles(s trServerPath, "*.jpg") ' Get the regular sized image Dim FullSizeImg As System.Drawing. Image FullSizeImg = System.Drawing. Image.FromFile( strFile)
' Create the delegate Dim dummyCallBack As System.Drawing. Image.GetThumbn ailImageAbort dummyCallBack = New System.Drawing. Image.GetThumbn ailImageAbort(A ddressOf ThumbnailCallba ck)
' Create the thumbnail Dim ThumbNailImg As System.Drawing. Image ThumbNailImg = FullSizeImg.Get ThumbnailImage( 160, 120, dummyCallBack, IntPtr.Zero) ThumbNailImg.Sa ve(Response.Out putStream, System.Drawing. Imaging.ImageFo rmat.Jpeg) pics.Add(ThumbN ailImg) Next
DataList1.DataS ource = pics DataList1.DataB ind()
P.S. In Esposito's book, he skips the dummy callback and just does this (which worked for me too)
Dim bmp As Image = New Bitmap(Server.M apPath("images\ myimage.jpg")
Dim newbmp As Image = bmp.GetThumbnai lImage(20, 20, *Nothing*, IntPtr.Zero
Enjoy
----- John wrote: ----
Thanks Bill. That was what I needed.
Bill Borg <an*******@disc ussions.microso ft.com> wrote in message news:<0F******* *************** ************@mi crosoft.com>.. Hi John First, in the item template of the datalist you need an image control Second, the image control needs a url (either src= or imageurl=, depending on whether it's a server control) Third, you can do the url the easy way or the harder-but-cooler way Easier way: Don't store your thumbnails in the array, instead write them to disk with temp names and store just the names in the array, then bind the source url to those names and you're off Harder way: Keep your images in the arraylist, but now you need a url that returns each image from memory. Consider GetImage.aspx, which returns a byte stream the browser will interpret as an image, with something like this in PageLoad Dim bmp As Image = New Bitmap(Server.M apPath("images\ myfile.jpg") Dim thumb as image = bmp.GetThumbnai lImage, etc Response.Conten tType = "image/jpeg bmp.Save(Respon se.OutputStream , Imaging.ImageFo rmat.Jpeg Now you bind the source url to GetImage.aspx and the thumbnail is fed from memory rather than disk Finally, in my example GetImage returns the *same* image each time, so if your directory has 30 images you'd get the same one each time...not good. A few ways to go about it, buy maybe the easiest is that you build your arraylist with just the file names, pass the file name to GetImage.aspx in a query string, and let GetImage convert it to a thumbnail and stream it back hth Bil P.S. If you're serious about it, there's a great discussion in Dino Esposito's book, Programming Microsoft ASP.NET ----- John wrote: ---- I am trying to convert the regular sized images in a directory t thumbnails and then display the thumbnails in a datalist. My cod below is displaying the first image and nothing else after it. Wha do I have to do to have the thumbnails displayed in my datalist? Thanks Dim strFile As Strin Dim pics As ArrayList = New ArrayLis ' Get image folder path on server - use "\" string if roo Dim strServerPath As String = Server.MapPath( "photos\" For Each strFile In System.IO.Direc tory.GetFiles(s trServerPath "*.jpg" ' Get the regular sized imag Dim FullSizeImg As System.Drawing. Imag FullSizeImg = System.Drawing. Image.FromFile( strFile ' Create the delegat Dim dummyCallBack As System.Drawing. Image.GetThumbn ailImageAbor dummyCallBack = Ne System.Drawing. Image.GetThumbn ailImageAbort(A ddressO ThumbnailCallba ck ' Create the thumbnai Dim ThumbNailImg As System.Drawing. Imag ThumbNailImg = FullSizeImg.Get ThumbnailImage( 160, 120 dummyCallBack, IntPtr.Zero ThumbNailImg.Sa ve(Response.Out putStream System.Drawing. Imaging.ImageFo rmat.Jpeg pics.Add(ThumbN ailImg Nex DataList1.DataS ource = pic DataList1.DataB ind( This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics |
by: John |
last post by:
I am trying to convert the regular sized images in a directory to
thumbnails and then display the thumbnails in a datalist. My code
below is displaying the first image and nothing else after it. What
do I have to do to have the thumbnails displayed in my datalist?
Thanks.
Dim strFile As String
Dim pics As ArrayList = New ArrayList
' Get image folder path on server - use "\" string if root
|
by: John |
last post by:
I am trying to convert the regular sized images in a directory to
thumbnails and then display the thumbnails in a datalist. My code
below is displaying the first image and nothing else after it. What
do I have to do to have the thumbnails displayed in my datalist?
Thanks.
Dim strFile As String
Dim pics As ArrayList = New ArrayList
' Get image folder path on server - use "\" string if root
|
by: John |
last post by:
I am trying to convert the regular sized images in a directory to
thumbnails and then display the thumbnails in a datalist. My code
below is displaying the first image and nothing else after it. What
do I have to do to have the thumbnails displayed in my datalist?
Thanks.
Dim strFile As String
Dim pics As ArrayList = New ArrayList
' Get image folder path on server - use "\" string if root
|
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Hi all. I'm using a simple thumbnail generating script in VB.NET/GDI.
It uses the GetThumbnailImage method.
It works great when resizing gifs. But when I resize a jpeg the
quality looks terrible. Here's a code snippet. Thanks.
Dim fullSizeImg as System.Drawing.Image
fullSizeImg =
System.Drawing.Image.FromFile(Server.MapPath(imageUrl))
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