Scanning with TWAIN in Silverlight 5 in-browser application

#1 Posted : Friday, February 17, 2012 6:39:27 AM(UTC)

Carlos_LEAD

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Attached is a project which demonstrates using TWAIN in-browser with Silverlight 5 via a COM object created with Leadtools’ .NET Twain DLLs. There are a few important things to note:

1.) In order for our Silverlight Controls to function properly in Silverlight 5 (for example the RasterImageViewer in this sample application), you have to make sure you reference System.Windows.Controls.dll version 5 in your project.

2.) Using COM objects in-browser will require elevated trust for the in-browser application. Instructions can be found here on how to enable Trusted Applications to run inside the browser: http://msdn.microsoft.com/en-us/library/gg192793(v=vs.95).aspx

Here are some detailed instructions for setting this up:
(***Please note that you need to perform all of these steps to get the example running)

To set the registry:

go to your start menu and search for “regedit”.
Open this program and navigate down to HKEY_LOCAL_MACHINE\Software\Microsoft\Silverlight\ (if you’re on a 32 bit OS) or HKEY_LOCAL_MACHINE\Software\Wow6432Node\Microsoft\Silverlight\ (if you’re on a 64 OS)
Now right click on the “Silverlight” registry and go to New->DWORD. Set the name of the dword to “AllowElevatedTrustAppsInBrowser” and set it’s value to 1 (0x00000001).

To create and install a test certificate:

(***Please note that this must be done in the project properties for the Silverlight Application—not the COM-Wrapper)

Open the properties of your project and under the “Signing” tab check the “sign the Xap file” box. Now click “Create Test Certificate” choose a password and click OK.
Click on “More Details… -> Install Certificate”. In the window that comes up, click “Next” and then select “Place all certificates in the following store”. Browse for the “Trusted Publisher” store and Finish. Now repeat this last step and install to the “Trusted Root Certification Authorities” store.
Go to the “Silverlight” Tab in your projects settings. First check the “Enable running application out of browser” button. Open the “Out-Of-Browser-Settings” and check the “Require elevated trust when running outside the browser” box. Click OK. Now disable the “Enable running application out of the browser button”. Finally enable the “Require elevated trust when running in-browser” box.

3.) As shown in the above instructions enabling the application to run as a trusted in-browser application requires that it also be trusted as an out of browser application. You can toggle running in browser/out of browser by checking/unchecking the “Enable running application out of browser” box. Just make sure that both in-browser and out of browser settings require elevated trust.

4.) Deploying in-browser applications which use COM objects in this manner will require end users to set the registry permissions manually (registry entries cannot be changed from within the browser).

File Attachment(s):

COM_TWAIN_SL5 .zip (19kb) downloaded 300 time(s).


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Scanning with TWAIN in Silverlight 5 in-browser application