June 2009 - Posts - Mel Balsamo

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Mel Balsamo

June 2009 - Posts

  • How to make an InfoPath control read-only after signing with the Electronic Signature Template Part

    Electronic Signatures allow you to add signatures to your solutions without the hassle of setting up digital certificates. Qdabra packaged the Electronic Signature template part so that you can reuse it in all of your forms. This blog post describes Qdabra’s Electronic Signature template part in full detail. If you have not learned about this XTP, please read that blog post before continuing.

    This document demonstrates an example of making a field un-editable after signing it with a signature image stored in a SharePoint library.

    Below is an image of a simple InfoPath form template that uses the Electronic Signature template part:


    In the main data source, we have:


    And in Preview mode:


    Notice that I can place my cursor inside the CompanyName field, which shows that it is not in read-only mode.

    If you have previously used Qdabra’s Electronic Signature template part in your solutions, you’re probably aware that the UserName and the PIN fields become hidden right after your signature image appears – that is, after you have entered the correct and valid credentials. Let’s see what the conditional formatting for our UserInfo section (which holds the UserName and the PIN fields) looks like.
     1. Double-click on the UserInfo section to see its properties.
     2. Go to the Display tab and click Conditional Formatting.
     3. You will see that there is only one conditional formatting set up for the UserInfo section. Click Modify.


    The condition “Signature is not blank” is the same as saying that the signature has a value – meaning, a signature image was successfully retrieved because the user entered valid credentials, and there is an existing signature image for that user in the SharePoint library. If that is true, then the UserInfo section becomes hidden. We will apply the same condition to make our CompanyName field read-only.

     4. Click OK three times to close all the open dialog boxes.
     5. Double-click on the CompanyName text box to open its properties.
     6. Go to the Display tab and click Conditional Formatting, then click Add.
     7. In the Conditional Format dialog’s first dropdown, select “Select a field or group”, and expand the nodes to get to Signature (/my:myFields/my:qESxtp/my:Sign/my:Signature), then click OK.
     8. In the second dropdown, select “is not blank”.
     9. Check the box that says “Read-only”.


     10. Click OK three times to close the dialogs.
     11. Preview your form template and fill it out, including the Company Name.


     12. When done, sign it with your electronic signature by entering your UserName and PIN, and checking the “Sign this document” checkbox.


    At this point, I can only highlight the Company Name and can no longer place my cursor inside the text box to edit it.

    This technique will prevent tampering with the data once a form has been signed, hence the security – yet another advantage of using Qdabra’s Electronic Signature template part.

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