Dynamics CRM 2011: restricting multiple attachments to an entity’s Notes

Requirement was very simple: to be able to add a single document to the notes control of an entity – but no more than one document.

There may be a more elegant way to accomplish this, but the way I found was to

• go to customize the entity's form
• configure Tab to open when the form opens
• add jQuery to the form's libraries list.
• put the following code in a web resource and add that web resource to the form's libraries list:

function EnforceSingleNote() {
    EnforceSingleNoteImpl();
    setInterval("EnforceSingleNoteImpl()", 500);
}

function EnforceSingleNoteImpl() {
    var notesInput = $(document.getElementById('notescontrol').contentWindow.document.getElementById('noteTextInput-create'));
    var notesContainer = notesInput.closest('.notesContainerScrollDiv');
    var nAttachments = notesContainer.find('.attachment').length;
    var notesTextBoxDivs = notesContainer.find('.notesTextBoxDiv');
    if (nAttachments > 0 && notesTextBoxDivs.length > 0) {
        notesTextBoxDivs.hide();
    }
    var notesTextCreate = notesContainer.find('.ms-crm-Note-Text-create');
    if (nAttachments > 0 && notesTextCreate.length > 0) {
        notesTextCreate.hide();
    }
}

• add an OnLoad event for the Notes control pointing to the EnforceSingleNote function in the web resource created before.

Basically, once every half a second, it checks whether there’s a note with an attachment. If there is, then it hides de controls where user can enter a new note.

You may be wondering why setInterval() instead of setTimeout(). Well, when you add a file, Dynamics creates on the fly a new “Enter a Note” textarea. The click handler needs to be set to that new textarea, too. Running this code once every second should be enough, and its perf hit should be minimal.