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/CascadingParametersDialog.java
|| DesignChoiceConstants.DATETIEM_FORMAT_TYPE_CUSTOM.equals( formatCategroy ) )
		{
			return true;
		}
		return false;
	}
	private void doPreview( String pattern )
	{
		String type = getSelectedDataType( );
		String formatStr = ""; 
		if ( DesignChoiceConstants.PARAM_TYPE_STRING.equals( type ) )
		{
			formatStr = new StringFormatter( pattern, ULocale.getDefault( ) ).format( DEFAULT_PREVIEW_STRING );
		}
		else if ( DesignChoiceConstants.PARAM_TYPE_DATETIME.equals( type ) )
		{
			formatStr = new DateFormatter( pattern ).format( new Date( ) );
		}
		else if ( DesignChoiceConstants.PARAM_TYPE_DECIMAL.equals( type )
				|| DesignChoiceConstants.PARAM_TYPE_FLOAT.equals( type ) )
		{
			formatStr = new NumberFormatter( pattern ).format( DEFAULT_PREVIEW_NUMBER );
		}
		else if ( DesignChoiceConstants.PARAM_TYPE_INTEGER.equals( type ) )
		{
			formatStr = new NumberFormatter( pattern ).format( DEFAULT_PREVIEW_INTEGER_NUMBER );
		}
		previewLable.setText( UIUtil.convertToGUIString( formatStr ) );
	}
	private String getColumnName( ScalarParameterHandle handle, String column )