Bug 177439 Need an easy way to determine default value for a dynamic parameter
Currently, I have to bring up the data set editor, preview the results in the data set and make a mental note of the value to use for a report parameter that depends on a data set. It would be nice to have a drop down on the default value field, such as <Select value> which when selected queries the data set and presents me with a list to select from.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/ParameterDialog.java
FormatBuilder formatBuilder = new FormatBuilder( style );
		formatBuilder.setInputFormat( formatCategroy, formatPattern );
		formatBuilder.setPreviewText( defaultValue );
		if ( formatBuilder.open( ) == OK )
		{
			formatCategroy = ( (String[]) formatBuilder.getResult( ) )[0];
			formatPattern = ( (String[]) formatBuilder.getResult( ) )[1];
			updateFormatField( );
			if ( refresh )
			{
				refreshValueTable( );
			}
		}
	}
	private boolean canBeBlank( )
	{
		boolean canBeBlank = false;
		if ( PARAM_CONTROL_LIST.equals( getSelectedControlType( ) )
				|| DesignChoiceConstants.PARAM_CONTROL_TEXT_BOX.equals( getSelectedControlType( ) ) )
		{
			if ( dirtyProperties.containsKey( CHECKBOX_ISREQUIRED ) )
			{
				canBeBlank = !( ( (Boolean) dirtyProperties.get( CHECKBOX_ISREQUIRED ) ).booleanValue( ) );
			}
			else
			{
				canBeBlank = !( inputParameter.isRequired( ) );
			}
		}
		return canBeBlank;