A screen is called as a result of a hyperlink. This may be a button click, a call from the recent list or any other selection from the interface. A URL of a Case's Summary Screen will look something like this:
http://localhost/CRM/eware.dll/Do?SID=198369875659391 &Act=281 &Mode=1 &CLk=T &Key0=8 &Key1=43 &Key2=57 &Key8=46 &T=Case
The URL contains a set of name/value pairs which are passed to the eware.dll to create the screen. The most important elements are the
- SID (Session ID)
- Act (Action Code)
- Key Values (Contextual Information)
The Key Values have been discussed in the article "Key Values in URLs".
The Session ID is created at logon is used to maintain the user session. No Sage CRM URL is valid without a valid SID.
The numeric Act code represents the internal action that is required to create the screen. The Action code triggers CRM to assemble the screen partially from Meta Data blocks and partially from hard coded elements.
The concept of the block has been discussed in the article "What is a Block in Sage CRM?".
Some screens have elements like "Pipeline" graphics which seem hardcoded and not at all based on Meta Data but as we can see from the discussion of the customization the Opportunity Pipeline contained in the article "Customizing the Opportunity Pipeline Summary Information" it may consist of metadata behaviours that we can access.