User`s guide

Null values in the data returned by the list of values are displayed as "null" in the drop-down list for that
prompt. Your users can select these values, and any parameters associated with that prompt receive
the null value. You can test for this functionality in the Crystal Reports formula language with the IsNull
function.
For more information, see "IsNull (fld)" in the online help.
21.8.5 Long lists of values
Because the number of items in a list of values (LOV) can be very large, numbering in the hundreds or
thousands, Crystal Reports handles these long LOVs by retrieving smaller batches of values at a time.
Crystal Reports displays a single batch of LOVs, and provides two options to the user to control the
list: the batch number and a simple text filter for limiting the number of items in the list.
The default number of items per batch retrieved in a long LOV is 200; however, you can change this
default number.
Changing the number of items in a long LOV
There are two methods for changing the number of items in a long LOVs.
When prompting the user, Crystal Reports retrieves the long LOV batch size from this Windows registry
location:
HKEY_CURRENT_USER\Software\Business Objects\Suite 12.0\Crystal Reports\Re
portView
If it does not already exist, create the DWord value called PromptingLOVBatchSize, and set the
value to the number of items in a batch.
Note:
Be careful to select Decimal as the base value before entering the batch size.
You can create or change a parameter in the Tomcat configuration file to set the batch size for long
LOVs. Open the following file:
{CR_install_folder}/Tomcat/webapps/CrystalReports/WEB-INF/web.xml
If it does not already exist, create this parameter:
<context-param>
<param-name>crystal_max_number_list_of_values</param-name>
<param-value>{number}</param-value>
</context-param>
Where {number} in the above example is the number of items in the batch.
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Parameter Fields and Prompts