Easy and convenient way for getting a client number would be using the Session
object for example. As long as you have a table column for this number in your database you can set it for every appointment as attribute from the code behind. This way it will use that value instead of the "23"
as shown in the sample project.
The provided solution will not require each user to select or type this client number since this approach is not creating a resource field to your advanced form.
Hope that this will lead you into right direction.
the Telerik team
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