Problem populating RasterImageList

I'm using Leadtools V15 with VS 2005 SP1.<br>
I'm reading several images from database and populating a rasterimageviewer control,<br>
I was using rasterimage paging but due the number of images (over the 500, <br>this was causing out of memory on the leadtools control, when reaching 300 image, it was using already 1.9 GB of RAM), <br>I decided to keep the images in a byte array
and have only one image at the time on the <br>rasterimageviewer control (using near 500MB RAM).<br><br>
After this change the rasterimagelist is throwing error when the load event finish.<br><br>

I noticed that after adding the image on the imagelist and initializing (next cycle of loop) the RstImageViewer the <br>
rasterImageLst.Items[previouspage].image is throwing execption when I watch the <br>variable on the QuickWatch.<br><br>

What am I doing wrong? <br>
<br>
while (db2dreader.Read())<br>
{<br>
i++;<br>
RstImgViewer.Image = null;<br>
// create byte array to retrieve the image from the recordset<br>
byteimg[i] = (Byte[])<br>db2dreader.GetDB2Blob(db2dreader.GetOrdinal("evalue")).Value;<br>
mstream = new MemoryStream(byteimg[i]);<br>

// insert the image (memory stream) in the rasterimage control <br>
RstImgViewer.Image = rasterCodecs.Load(mstream);<br>

// add on the thumbnails<br>
tempItem = new RasterImageListItem();<br>
tempItem.Image=RstImgViewer.Image;<br>
tempItem.Text=i.ToString();<br>
rasterImageLst.Items.Add(tempItem);<br>

mstream.Close();<br>
mstream = null;<br>
}<br>


<br>
-----------------------------------------------<br>
Object reference not set to an instance of an object.<br>


at Leadtools.RasterImage.GetImageWidthDpi(Boolean useDpi)<br>
at Leadtools.WinForms.RasterImageList.a(Graphics A_0, RasterImageListItem A_1, Rectangle A_2)<br>
at Leadtools.WinForms.RasterImageList.b(Graphics A_0, RasterImageListItem A_1, Rectangle A_2)<br>
at Leadtools.WinForms.RasterImageList.e(Graphics A_0, RasterImageListItem A_1, Rectangle A_2)<br>
at Leadtools.WinForms.RasterImageList.OnPaint(PaintEventArgs e)<br>
at System.Windows.Forms.Control.PaintWithErrorHandling(PaintEventArgs e, Int16 layer, Boolean disposeEventArgs)<br>
at System.Windows.Forms.Control.WmPaint(Message& m)<br>
at System.Windows.Forms.Control.WndProc(Message& m)<br>
at Leadtools.WinForms.RasterImageList.WndProc(Message& m)<br>
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)<br>
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)<br>
at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)<br>
at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)<br>
at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData)<br>
at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)<br>
at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)<br>
at System.Windows.Forms.Application.Run(Form mainForm)<br>
at WindowsApplication1.Program.Main() in Z:\Visual Csharp\scanmgr\WindowsApplication1\Program.cs:line 19<br><br>

Please create a small working project (not your full application) that shows the problem. Send the project in a new email to support@leadtools.com and mention this forum post in your email.

Please put it in a ZIP or RAR file to ensure our servers accept it.

Thanks,
Maen Badwan
LEADTOOLS Technical Support

Was this issue ever solved. I am getting the same error. I'm using this code snip-it right out of the sample project.

if (_viewer.Image == null)
{
_viewer.Image = e.Image;
}
else
{
_viewer.Image.AddPage(e.Image);
_viewer.Image.Page = _viewer.Image.PageCount;
}

However on the second pass it always throws an object reference error. I checked both objects before calling the addpage() methods and they look valid, but that method fails every time and I get this stack trace.

at Leadtools.RasterImage.GetImageWidthDpi(Boolean useDpi)
at Leadtools.WinForms.RasterImageViewer.b(Object A_0, RasterImageChangedEventArgs A_1)
at Leadtools.RasterImage.AddPage(RasterImage image)
at TestMultipage.MainForm._twain_AcquirePage(Object sender, TwainAcquirePageEventArgs e) in D:\Projects\...\MainForm.cs:line 202

I don't know what version are you using but on V15 the way to add a new page to a rasterimageviwer is using .InsertPage (at least the way that work for me ;-) )

something like...

if (_viewer.Image == null)
{
_viewer.Image = e.Image;
}
else
{
_viewer.Image.InsertPage(Pagecounter++,e.image)
_viewer.Image.Page = Pagecounter
}


and btw my issue on the rasterimagelist was resolved using RstImgViewer.AutoDisposeImages = false; which is true by default....


Carlos

I tried making the changes you suggested but it looks like Insert() just calls addpage().
Here is the new stack trace:
at Leadtools.RasterImage.GetImageWidthDpi(Boolean useDpi)
at Leadtools.WinForms.RasterImageViewer.b(Object A_0, RasterImageChangedEventArgs A_1)
at Leadtools.RasterImage.OnChanged(RasterImageChangedEventArgs e)
at Leadtools.RasterImage.AddPage(RasterImage image)
at Leadtools.RasterImage.InsertPage(Int32 index, RasterImage image)

I am using version 16. I also tried the AutoDisposeImages, but had not luck.

Thanks for trying to help me out, I appreciate it. Hopefully I will hear from a LeadTools support associate and get to the bottom of this.

Thanks,
-Chris

Looks like using this solved the issue.
_viewer.Image = new RasterImage(e.Image);

I was trying to use this based off the sample application (TwainMultiScan)
_viewer.Image = e.Image;