Parameter Properties

Table 10.2 outlines several properties of parameters.

Table 10.2. Parameter Properties

Property Name	Expected Value	Description
Name	String	The actual and unique name of the parameter within the scope of the report. This is what the parameter is referred to when referencing it in the Globals collection.
Parameter Type	Enum :String (default), Integer, DateTime, Boolean, Float	The data type in which to expect the parameter. It defaults to string, but you can choose a different data type from the drop-down list. If the report parameter values come from a query, the return type for the query must match the type specified here. Because .NET CLR is a strongly typed system, SSRS is as well. It returns an error if a string is passed in for what is supposed to be a number value. For a Boolean value, the Report Server simply creates a radio button list with true/false as the only options.
Prompt	String	A friendly message to pass to the user who enters the parameter data. If it is left empty, and a default value is specified for the parameter, the user is not asked to input the value because the report will use the defaulted value. If the prompt is empty, and no default value is specified, the report will not run.
MultiValue	Boolean	New in SSRS 2005; this option allows you to select multiple values by checking check boxes in a drop-down list, instead of displaying a single text box or drop-down list.
Hidden	Boolean	The value of this should not appear in the report, but it can still be set at runtime.
Internal	Boolean	A parameter that cannot be changed at runtime. A consumer of a published report will never see this as a parameter.
Allow Null	Boolean	A parameter that can have a null value.
Allow Empty string	Boolean	An empty string is a valid value.

Later on in the chapter, you will walk through creating report parameters. For now, all you need to know is that to create parameters, simply click the Add button in the Report Parameters dialog box and simply fill in the values.