Use custom functions of Crystal Reports for code reuse

 

Generally, we can use formulas to implement some special functions, but for some situations that need to be processed repeatedly
User-defined functions can be used for implementation.

On the formula editing page, you can see two items in the upper left corner:

Report user-defined functions and reserve User-Defined Functions

A report user-defined function is only available in a single report template. Different templates cannot be shared.
The custom function of the repository is unavailable for separate Crystal Reports and. Net versions. This is a function of the Crystal Report Server version or BOE.
After the function is converted to a custom function of the repository, the function is stored in the system database, so that different reports can be used for function sharing.
However, there is no impact on a single function.

Now let's talk about the use of user-defined functions in combination with an instance.
There is a proposition that shows a Date Field October 28, 2008]
This effect cannot be achieved using a custom date format. Although we can use a formula, it is very troublesome to write formulas for multiple such fields each time.
So here we choose to use a custom function.

Switch to the formula Editor interface, right-click [report user-defined functions], and create a function named mydate.
Switch the syntax to Basic (you can also use the Crystal syntax), and then write the function body.

I will not explain the specific function content. Here I use two functions to implement this function.
Another function is ChNumber, which is used to process reuse in mydate.

The function body is as follows:

 

'For date conversion
Function myDate (date1 as date)
Dim sY as string
Dim sM as string
Dim sD as string
'Retrieve year, month, and day
SY = totext (year (date1), 0)
SM = totext (month (date1), 0)
SD = totext (day (date1), 0)
MyDate = chNumber (sY, "0") & "year" & chNumber (sM, "1") & "month" & chNumber (sD, "1") & "day"
End Function

 

The type of the parameter t to be processed. 0 is the year, replace the characters one by one, 1 is the month and date, and 10 carry
Function ChNumber (s as string, t as string)
Dim s0 as string
'Replace all first
S0 = Replace (s ,",","")
S0 = Replace (s0, "0", "0 ")
S0 = Replace (s0, "1", "1 ")
S0 = Replace (s0, "2", "2 ")
S0 = Replace (s0, "3", "3 ")
S0 = Replace (s0, "4", "4 ")
S0 = Replace (s0, "5", "5 ")
S0 = Replace (s0, "6", "6 ")
S0 = Replace (s0, "7", "7 ")
S0 = Replace (s0, "8", "8 ")
S0 = Replace (s0, "9", "9 ")
'Perform decimal processing on the day of the month
If t = "1" then
'Decimal processing, adding a 10 character to the middle of two digits
If Len (s0) = 2 Then
S0 = left (s0, 1) & "10" & right (s0, 1)
'Processing is just 10, 20, 30.
If left (s0, 1) = "1" then s0 = replace (s0, "10", "10 ")
If right (s0, 1) = "zero" then s0 = replace (s0, "zero ","")
End if
End if
ChNumber = s0
End Function

 

Then let's do a simple test:

Create a date parameter xx,

Create a formula yy with the following content: mydate ({? Xx })

Shown as: January 1, October 28, 2008