private static void GetPrintPreviewPage(object sender, GetPreviewPageEventArgs e)
{
Interlocked.Exchange(ref currentPreviewPage, e.PageNumber - 1);
PageLoadState pageLoadState = printPreviewPages[e.PageNumber - 1];
if (!pageLoadState.Ready)
{
// Notify the user that some content is not available yet
// Apps may also opt to don't show preview untill everything is complete and just use await IsReadyAsync
//rootPage.NotifyUser("Image loading not complete, previewing only text", NotifyType.ErrorMessage);
}
// Set the preview even if images failed to load properly
printDocument.SetPreviewPage(e.PageNumber, pageLoadState.Page);
}
private static RichTextBlockOverflow AddOnePrintPreviewPage(RichTextBlockOverflow lastRTBOAdded, PrintPageDescription printPageDescription)
{
// Create a cavase which represents the page
Canvas page = new Canvas();
page.Width = printPageDescription.PageSize.Width;
page.Height = printPageDescription.PageSize.Height;
PageLoadState pageState = new PageLoadState(page, printPreviewPages.Count);
pageState.ReadyAction = async(pageNumber, currentPage) =>
{
// Ignore if this is not the current page
if (Interlocked.CompareExchange(ref currentPreviewPage, currentPreviewPage, pageNumber) == pageNumber)
{
await Window.Current.Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal, () =>
{
//await new Windows.UI.Popups.MessageDialog("Content loaded").ShowAsync();
printDocument.SetPreviewPage(pageNumber + 1, currentPage);
});
}
};
// Create a grid which contains the actual content to be printed
Grid content = new Grid();
// Get the margins size
// If the ImageableRect is smaller than the app provided margins use the ImageableRect
double marginWidth = Math.Max(printPageDescription.PageSize.Width - printPageDescription.ImageableRect.Width,
printPageDescription.PageSize.Width * ApplicationContentMarginLeft * 2);
double marginHeight = Math.Max(printPageDescription.PageSize.Height - printPageDescription.ImageableRect.Height,
printPageDescription.PageSize.Height * ApplicationContentMarginTop * 2);
// Set content size based on the given margins
content.Width = printPageDescription.PageSize.Width - marginWidth;
content.Height = printPageDescription.PageSize.Height - marginHeight;
// Set content margins
content.SetValue(Canvas.LeftProperty, marginWidth / 2);
content.SetValue(Canvas.TopProperty, marginHeight / 2);
// Add the RowDefinitions to the Grid which is a content to be printed
RowDefinition rowDef = new RowDefinition();
rowDef.Height = new GridLength(2.5, GridUnitType.Star);
content.RowDefinitions.Add(rowDef);
rowDef = new RowDefinition();
rowDef.Height = new GridLength(3.5, GridUnitType.Star);
content.RowDefinitions.Add(rowDef);
rowDef = new RowDefinition();
rowDef.Height = new GridLength(1.5, GridUnitType.Star);
content.RowDefinitions.Add(rowDef);
// If lastRTBOAdded is null then we know we are creating the first page.
bool isFirstPage = lastRTBOAdded == null;
FrameworkElement previousLTCOnPage = null;
RichTextBlockOverflow rtbo = new RichTextBlockOverflow();
// Create the linked containers and and add them to the content grid
if (isFirstPage)
{
// The first linked container in a chain of linked containers is is always a RichTextBlock
RichTextBlock rtbl = new RichTextBlock();
rtbl.SetValue(Grid.RowProperty, 0);
rtbl = AddContentToRTBl(rtbl);
int a = rtbl.Blocks.Count();
rtbl.Foreground = new SolidColorBrush(Windows.UI.Colors.Black);
content.Children.Add(rtbl);
// Save the RichTextBlock as the last linked container added to this page
previousLTCOnPage = rtbl;
}
else
{
// This is not the first page so the first element on this page has to be a
// RichTextBoxOverflow that links to the last RichTextBlockOverflow added to
// the previous page.
rtbo = new RichTextBlockOverflow();
rtbo.SetValue(Grid.RowProperty, 0);
content.Children.Add(rtbo);
// Keep text flowing from the previous page to this page by setting the linked text container just
// created (rtbo) as the OverflowContentTarget for the last linked text container from the previous page
lastRTBOAdded.OverflowContentTarget = rtbo;
// Save the RichTextBlockOverflow as the last linked container added to this page
previousLTCOnPage = rtbo;
}
if (ShowText)
{
// Create the next linked text container for on this page.
rtbo = new RichTextBlockOverflow();
rtbo.SetValue(Grid.RowProperty, 1);
// Add the RichTextBlockOverflow to the content to be printed.
content.Children.Add(rtbo);
// Add the new RichTextBlockOverflow to the chain of linked text containers. To do this we much check
// to see if the previous container is a RichTextBlock or RichTextBlockOverflow.
if (previousLTCOnPage is RichTextBlock)
{
((RichTextBlock)previousLTCOnPage).OverflowContentTarget = rtbo;
}
else
{
((RichTextBlockOverflow)previousLTCOnPage).OverflowContentTarget = rtbo;
}
// Save the last linked text container added to the chain
previousLTCOnPage = rtbo;
// Create the next linked text container for on this page.
rtbo = new RichTextBlockOverflow();
rtbo.SetValue(Grid.RowProperty, 2);
content.Children.Add(rtbo);
// Add the new RichTextBlockOverflow to the chain of linked text containers. We don't have to check
// the type of the previous linked container this time because we know it's a RichTextBlockOverflow element
((RichTextBlockOverflow)previousLTCOnPage).OverflowContentTarget = rtbo;
}
// We are done creating the content for this page. Add it to the Canvas which represents the page
page.Children.Add(content);
// Add the newley created page to the printing root which is part of the visual tree and force it to go
// through layout so that the linked containers correctly distribute the content inside them.
PrintingRoot.Children.Add(page);
PrintingRoot.InvalidateMeasure();
PrintingRoot.UpdateLayout();
// Add the newley created page to the list of pages
printPreviewPages.Add(pageState);
// Return the last linked container added to the page
return(rtbo);
}
