
Replacement Parameter provides a great way to pass parameter to the Configuration in Unified Service Desk. The Parameter can be value of any key value pair within the context. Replacement Parameter is used to replace the current value of the Key value dictionary during execution time.
Replacement Parameter is used to pull data throughout the application from data element that has been captured during execution of Unified Service Desk. The context consists of Name value parameter use change during the different steps of the application execution.
Replacement parameter can be used in various places such as scriptlets, session lines, session overview, entity search, CTI, generating querystring, hosted controls, action call, etc. Replacement parameter has a specific syntax.
- - View the Replacement Parameters in Unified Service Desk
- - Replacement parameter can be viewed inside the Debugger window in Unified Service Desk. Below are the steps:
- - Open Unified Service Desk with a sample package installed.

As shown below, click on the Debug Menu, then system will open Debugger Hosted control in the MainPanel.

In the Debugger, click Data Parameters to view the replacement parameters.
System Replacement Parameters
There are few predefined Replacement Parameters available in Unified Service Desk. The names of the predefined Replacement Parameters start with $. USD has the following predefined Replacement Parameters:
- - $Context
- - $Debug
- - $Global
- - $Panel
- - $Resources
- - $Return
- - $Session
- - $Settings
- - $Subject
- - $User
Replacement Keys
One of the Key concept of Replacement Parameter is Replacement Keys. Replacement Key is normally used in conjunction with Replacement Parameter which gives extra meaning to the Replacement Parameter as below:
Replacement Key |
Description |
+ |
This key, when present, will replace a null or non-existent key with an empty string.
For example: In the scenario where account.name is undefined, calling [[account.name]] would result in a “Not all parameters in action call are available, aborting action call.” error. This will stop processing the rule or line item being executed.
However, [[account.name]+] will return a blank, and not raise the replacement key error.
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Few Replacement Parameter tips:
- - If a value might return a null, use [[afield]+], as this will handle nulls correctly.
- - If you are constructing a url, use the “]u]”, as this adds %20 for spaces etc.
- - If the string might contain “special” characters such as “<“, the use “]x]” to ensure they display correctly.
- - You can combine combinations, like “[[telephone1]+x]”, for a telephone number that might be null and might contain “special” characters.
Few Replacement Parameter examples:
- - To return the start time of a session use [[$Session.StartTime]g]
- - Use this [[$User.fullname]g] to return the name of the current user. (Useful in agent scripts etc.)
- - This will return the number of open sessions [[$Session.Count]g], and this [[$Global.maxNumberOfSessions]] will return the maximum number of session possible.
For more details and list of Replacement Keys and Specialized handlers, please visit https://msdn.microsoft.com/en-us/library/dn864934.aspx
