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
{
				ExpressionBuilder expressionBuilder = new ExpressionBuilder( getExpression( columnChooser.getText( ) ) );
				expressionBuilder.setExpressionProvier( new ParameterExpressionProvider( inputParameter,
						dataSetChooser.getText( ) ) );
				if ( expressionBuilder.open( ) == OK )
				{
					setExpression( columnChooser, expressionBuilder.getResult( )
							.trim( ) );
				}
			}
		} );
		
		createLabel( composite, LABEL_SELECT_DISPLAY_TEXT );
		
		
		displayTextChooser = new Combo( composite, SWT.BORDER | SWT.DROP_DOWN );
		displayTextChooser.setLayoutData( new GridData( GridData.FILL_HORIZONTAL ) );
		Button displayTextExprButton = new Button( composite, SWT.PUSH );
		
		setExpressionButtonImage( displayTextExprButton );
		displayTextExprButton.setToolTipText( Messages.getString( "ParameterDialog.toolTipText.OpenExprButton" ) );
		displayTextExprButton.addSelectionListener( new SelectionAdapter( ) {
			public void widgetSelected( SelectionEvent event )
			{
				ExpressionBuilder expressionBuilder = new ExpressionBuilder( getExpression( displayTextChooser.getText( ) ) );
				expressionBuilder.setExpressionProvier( new ParameterExpressionProvider( inputParameter,
						dataSetChooser.getText( ) ) );
				if ( expressionBuilder.open( ) == OK )
				{
					setExpression( displayTextChooser,