Using the sizeToPage attribute to format pages

A PrintDataGrid page consists of the rows that are visible in the control’s current view. Suppose, for example, that a PrintDataGrid control has a height of 130 pixels. The total height of each row and header is 30 pixels, and the control’s data provider has 10 rows. In this situation, the printed PrintDataGrid page contains only three complete data rows, plus the header. ThesizeToPageproperty specifies whether to include a fourth and partial data row.

ThesizeToPageproperty, which istrueby default, causes the PrintDataGrid control to remove any partially visible or empty rows and to resize itself to include only complete rows in the current view. For the data grid described in the preceding paragraph, when this property istrue, the DataGrid shrinks to show three complete data rows, and no incomplete rows; if the attribute isfalse, the grid includes a partial row at the bottom.

The following properties provide information on page sizing that are affected by thesizeToPageproperty:

currentPageHeight

originalHeight

In most applications, you leave thesizeToPageattribute at its default value (true), and use theheightproperty to determine the grid height.

ThesizeToPageproperty does not affect the way the page breaks when a single PrintDataGrid control page is longer than a print page. To print multipage data grids without splitting rows, you must divide the grid items into multiple views by using thenextPage()method, as described in the following section.

Using the nextPage() method and validNextPage property to print multiple pages

ThevalidNextPageproperty istrueif the PrintDataGrid control has data beyond the rows that fit on the current print page. You use it to determine whether you need to format and print an additional page.

ThenextPage()method lets you page through the data provider contents by setting the first row of the PrintDataGrid control to be the data provider row that follows the last row of the previous PrintDataGrid page. In other words, thenextPage()method increases the grid’sverticalScrollPositionproperty by the value of the grid’srowCountproperty.

The following code shows a loop that prints a grid using multiple pages, without having rows that span pages:

// Queue the first page. printJob.addObject(thePrintView); // While there are more pages, print them. while (thePrintView.myDataGrid.validNextPage) {     //Put the next page of data in the view.     thePrintView.myDataGrid.nextPage();     //Queue the additional page.     printJob.addObject(thePrintView); }

The section Example: Printing with multipage PrintDataGrid controls shows how to use thenextPage()method to print a report with a multipage data grid.

Updating the PrintDataGrid layout

When you use a PrintDataGrid control to print a single data grid across multiple pages, you queue each page of the grid individually. If your application customizes each page beyond simply using thenextPage()method to page through the PrintDataGrid, you must call thevalidateNow()method to update the page layout before you print each page, as shown in Print output component.

The following code shows the multipage print application file:

<?xml version="1.0"?><!-- printing\MultiPagePrint.mxml --><s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"     xmlns:s="library://ns.adobe.com/flex/spark"     xmlns:mx="library://ns.adobe.com/flex/mx"     initialize="initData();">    <fx:Script>    <![CDATA[        import mx.printing.*;        import mx.collections.ArrayCollection;        // Import the MXML custom print view control.        import myComponents.FormPrintView;        // Declare variables and initialize simple variables.        // The dgProvider ArrayCollection is the DataGrid data provider.        // It must be bindable because you change its contents dynamically.        [Bindable]        public var dgProvider:ArrayCollection;        public var footerHeight:Number = 20;        public var prodIndex:Number;        public var prodTotal:Number = 0;                // Data initialization, called when the application initializes.        public function initData():void {            // Create the data provider for the DataGrid control.            dgProvider = new ArrayCollection;         }                // Fill the dgProvider ArrayCollection with the specified items.        public function setdgProvider(items:int):void {             // First initialize the index and clear any existing data.            prodIndex=1;            dgProvider.removeAll();                        // Fill the ArrayCollection, and calculate a product total.            // For simplicity, it increases the Index field value by            // 1, and the Qty field by 7 for each item.            for (var z:int=0; z<items; z++)             {                var prod1:Object = {};                prod1.Qty = prodIndex * 7;                prod1.Index = prodIndex++;                prodTotal += prod1.Qty;                 dgProvider.addItem(prod1);            }        }        // The function to print the output.        public function doPrint():void {            // Create a FlexPrintJob instance.            var printJob:FlexPrintJob = new FlexPrintJob();                        // Start the print job.            if (printJob.start()) {                // Create a FormPrintView control                 // as a child of the application.                var thePrintView:FormPrintView = new FormPrintView();                addElement(thePrintView);                                // Set the print view properties.                thePrintView.width=printJob.pageWidth;                thePrintView.height=printJob.pageHeight;                thePrintView.prodTotal = prodTotal;                                // Set the data provider of the FormPrintView                 // component‘s DataGrid to be the data provider of                 // the displayed DataGrid.                thePrintView.myDataGrid.dataProvider =                     myDataGrid.dataProvider;                                // Create a single-page image.                thePrintView.showPage("single");                                // If the print image‘s DataGrid can hold all the                  // data provider‘s rows, add the page to the print job.                 if(!thePrintView.myDataGrid.validNextPage)                {                    printJob.addObject(thePrintView);                }                // Otherwise, the job requires multiple pages.                else                {                    // Create the first page and add it to the print job.                    thePrintView.showPage("first");                    printJob.addObject(thePrintView);                    thePrintView.pageNumber++;                                        // Loop through the following code                     // until all pages are queued.                    while(true)                    {                        // Move the next page of data to the top of                         // the PrintDataGrid.                        thePrintView.myDataGrid.nextPage();                        // Try creating a last page.                        thePrintView.showPage("last");                          // If the page holds the remaining data, or if                         // the last page was completely filled by the last                          // grid data, queue it for printing.                        // Test if there is data for another                         // PrintDataGrid page.                        if(!thePrintView.myDataGrid.validNextPage)                         {                            // This is the last page;                             // queue it and exit the print loop.                            printJob.addObject(thePrintView);                            break;                        }                        else                        // This is not the last page. Queue a middle page.                         {                            thePrintView.showPage("middle");                            printJob.addObject(thePrintView);                            thePrintView.pageNumber++;                        }                    }                }                // All pages are queued; remove the FormPrintView                 // control to free memory.                removeElement(thePrintView);            }            // Send the job to the printer.            printJob.send();        }    ]]>    </fx:Script>    <!-- The form that appears on the user‘s system.-->    <mx:Form id="myForm" width="80%">        <mx:FormHeading label="Product Information"/>                <mx:DataGrid id="myDataGrid" dataProvider="{dgProvider}">                <mx:columns>                    <mx:DataGridColumn dataField="Index"/>                    <mx:DataGridColumn dataField="Qty"/>                </mx:columns>            </mx:DataGrid>        <mx:Text width="100%"             text="Specify the number of lines and click Fill Grid first.             Then you can click Print."/>        <mx:TextInput id="dataItems" text="35"/>        <mx:HBox>            <mx:Button id="setDP"                 label="Fill Grid"                click="setdgProvider(int(dataItems.text));"/>            <mx:Button id="printDG"                 label="Print"                 click="doPrint();"/>        </mx:HBox>    </mx:Form></s:Application>

The executing SWF file for the previous example is shown below:

The following lines show the FormPrintView.mxml custom component file:

<?xml version="1.0"?><!-- printing\myComponents\FormPrintView.mxml --><mx:VBox xmlns:fx="http://ns.adobe.com/mxml/2009"     xmlns:s="library://ns.adobe.com/flex/spark"     xmlns:mx="library://ns.adobe.com/flex/mx"     xmlns:MyComp="myComponents.*"     backgroundColor="#FFFFFF"    paddingTop="50" paddingBottom="50" paddingLeft="50">    <fx:Script>        <![CDATA[            import mx.core.*                        // Declare and initialize the variables used in the component.            // The application sets the actual prodTotal value.            [Bindable]            public var pageNumber:Number = 1;            [Bindable]            public var prodTotal:Number = 0;            // Control the page contents by selectively hiding the header and            // footer based on the page type.            public function showPage(pageType:String):void {                if(pageType == "first" || pageType == "middle") {                    // Hide the footer.                    footer.includeInLayout=false;                    footer.visible = false;                }                if(pageType == "middle" || pageType == "last") {                    // The header won‘t be used again; hide it.                    header.includeInLayout=false;                    header.visible = false;                }                if(pageType == "last") {                    // Show the footer.                    footer.includeInLayout=true;                    footer.visible = true;                }                //Update the DataGrid layout to reflect the results.                validateNow();            }        ]]>    </fx:Script>    <!-- The template for the printed page,         with the contents for all pages. -->    <mx:VBox width="80%" horizontalAlign="left">        <mx:Label text="Page {pageNumber}"/>    </mx:VBox>    <MyComp:FormPrintHeader id="header"/>        <!-- The sizeToPage property is true by default, so the last        page has only as many grid rows as are needed for the data. -->    <mx:PrintDataGrid id="myDataGrid" width="60%" height="100%">    <!-- Specify the columns to ensure that their order is correct. -->        <mx:columns>            <mx:DataGridColumn dataField="Index" />            <mx:DataGridColumn dataField="Qty" />        </mx:columns>    </mx:PrintDataGrid>        <!-- Create a FormPrintFooter control         and set its prodTotal variable. -->    <MyComp:FormPrintFooter id="footer" pTotal="{prodTotal}"/></mx:VBox>

The following lines show the FormPrintHeader.mxml file.

<?xml version="1.0"?><!-- printing\myComponents\FormPrintHeader.mxml --><mx:VBox xmlns:fx="http://ns.adobe.com/mxml/2009"     xmlns:s="library://ns.adobe.com/flex/spark"     xmlns:mx="library://ns.adobe.com/flex/mx"     width="60%"    horizontalAlign="right" >    <mx:Label text="This is a placeholder for first page contents"/></mx:VBox>

The following lines show the FormPrintFooter.mxml file:

<?xml version="1.0"?><!-- printing\myComponents\FormPrintFooter.mxml --><mx:VBox xmlns:fx="http://ns.adobe.com/mxml/2009"     xmlns:s="library://ns.adobe.com/flex/spark"     xmlns:mx="library://ns.adobe.com/flex/mx"     width="60%"    horizontalAlign="right">        <!-- Declare and initialize the product total variable. -->    <fx:Script>        <![CDATA[            [Bindable]            public var pTotal:Number = 0;        ]]>        </fx:Script>    <mx:Label text="Product Total: {pTotal}"/></mx:VBox>

[Bindable]private var dpHierarchy:ArrayCollection = new ArrayCollection([  {Region:"Southwest", children: [     {Region:"Arizona", children: [         {Territory_Rep:"Barbara Jennings", Actual:38865, Estimate:40000},         {Territory_Rep:"Dana Binn", Actual:29885, Estimate:30000}]},       {Region:"Central California", children: [         {Territory_Rep:"Joe Smith", Actual:29134, Estimate:30000}]},       {Region:"Nevada", children: [         {Territory_Rep:"Bethany Pittman", Actual:52888, Estimate:45000}]},       {Region:"Northern California", children: [         {Territory_Rep:"Lauren Ipsum", Actual:38805, Estimate:40000},         {Territory_Rep:"T.R. Smith", Actual:55498, Estimate:40000}]},       {Region:"Southern California", children: [         {Territory_Rep:"Alice Treu", Actual:44985, Estimate:45000},         {Territory_Rep:"Jane Grove", Actual:44913, Estimate:45000}]}  ]}]);