Instructor s Notes Programming Logic Printing Reports. Programming Logic. Printing Custom Reports

Transcription

1 Instructor s Programming Logic Printing Reports Programming Logic Quick Links & Text References Printing Custom Reports Printing Overview Page 575 Linking Printing Objects No book reference Creating a Print Document Pages Sharing the Event Argument No book reference Setting Page Defaults No book reference Adding Text Pages Defining Fonts No book reference Adding Images No book reference Drawing Lines No book reference Drawing Thick Lines (Filled Rectangles) No book reference Creating Multipage Reports No book reference Other Print Methods No book reference MarginBounds No book reference Check Boxes No book reference String Width No book reference Page 1 of 9

2 Instructor s Programming Logic Printing Reports Printing Objects The primary object required is a print document Contains the results of print commands Ability to print text, images, graphics objects Most applications also implement a preview dialog that allows the user to preview the document before printing I always force users to preview before they print Preview includes a Print button that allows the user to print directly from the preview window to the default printer Need a print dialog to allow the user to change printer or printer settings. The preview and print dialogs must both be linked to the print document so the dialogs know what to print Print Document Print Preview To add the required printing objects, first open the Printing group in the VB toolbox Add the following items to your form These items will appear in the Component Tray at the bottom of the window I use the pd prefix followed by the name of the report when naming the object I always call this object dlgpreview (optional) dlgprint Include this if you want to give the user a way to select printers or change printer settings Note there is also a Page Setup Dialog. I don t normally use this because my reports are always custom built to fit the page just one way. Page 2 of 9

3 Instructor s Programming Logic Printing Reports Linking Print Objects Select dlgpreview Change Document property to the name of your print document Repeat for dlgprint if you included one This can actually be done in code, allowing you to use dlgpreview to display various reports. Private Sub btnprint_click(byval sender As System.Object, _ ByVal e As System.EventArgs) _ Handles btnprint.click SetPageDefaults() dlgpreview.printpreviewcontrol.startpage = 0 dlgpreview.document = pdmyreport dlgpreview.windowstate = FormWindowState.Maximized 'Note: WindowState doesn't appear in properties list dlgpreview.showdialog() End Sub SetPageDefaults sets the margins and orientation of the report (see below). This is procedure you must write, though you can name it anything you want. dlgpreview remembers the last page number you were viewing. When you view a different document, it shows the same page in that document. The StartPage command above ensures every document starts by displaying the first page. dlgpreview.document = pdmyreport links the print document (pdmyreport) to the report preview dialog box (using the Document property) Most reports are quite wide and long. Setting the WindowState makes the preview dialog appear full screen. The user can still restore/resize it, but it starts out maximized. Creating a Print Document Double-click the print document control This opens the PrintPage event Add Imports.System.Drawing.Printing to the form code (above the Public Class statement) Add code to the PrintPage event The parameter e contains all the routines you need to add text, pictures, lines etc. to the page. Page 3 of 9

4 Instructor s Programming Logic Printing Reports Sharing the Event Argument Most of the reports I ve created are fairly complex so I break the code into procedures. However, the e parameter to PrintPage is needed by all those procedures. To share the e parameter, I first declare a form-level variable to hold a copy of e 'Save access event arguments for all procedures Private ev As PrintPageEventArgs Then, I copy the contents of e into ev as the very first line in PrintPage 'Make event arguments available to other procedures ev = e I then use ev (instead of e) to access the Graphics object to add things to the report. Setting Page Defaults Before adding items to the print document, you should set its margins This example also includes code to define commonly used page positions With pd.defaultpagesettings ' L R T B.Margins = New Margins(50, 50, 50, 50) 'All measurements in 100ths of an inch '.Landscape = True 'Determine location of center and right margin. 'Bounds defines the total width of page centerpos =.Bounds.Width / 2.0F rightpos =.Bounds.Right -.Margins.Right 'Width and right seem to be the same End With 'Used to center align strings on a point centerformat.alignment = StringAlignment.Center 'Used to right align strings on a point rightformat.alignment = StringAlignment.Far Page 4 of 9

5 Instructor s Programming Logic Printing Reports I usually place this code in a procedure and invoke it on form load In the first example on page 3, I called it SetPageDefaults Note we are changing the print document s (pd) default page settings The example above sets ½ inch margins all around (50 / 100) Page settings can also change the page orientation centerpos and rightpos can be used to center or right align objects when placing them on the print document These are form-level variables (Single or Double) Bounds is actually the width and height of the page Margins refers to the margin settings set previously centerformat and rightformat allow you to quickly change the alignment of text These are form-level variables of type StringFormat (from import file) Adding Text to the Print Document Tip: Save yourself some typing: put ev.graphics in a With statement. ev.graphics.drawstring(text, font, color, x, y, [alignment]) text: the text (variable or literal) you want added to the document font: the font that should be used for this text I define different font variables for titles, normal text, headings, etc. Dim nfont As New Font("Times New Roman", 12) 'Normal font Dim nbfont As New Font("Times New Roman", 12, FontStyle.Bold) Then, place the font name (nfont, nbfont) in this parameter location Define a font variable for every different font (or different font size, or different font style) in your report (I often have 10 or more) I normally define these as form-level variables so all procedures have access to them. Color: the font color Use the Brushes collection (from import) to choose a color Brushes.Black Brushes.Maroon x, y: the position on the page (measured in 1/100s of an inch) where the text should start. Change x to centerpos (see defaults) to center text on the page Change x to rightpos (see defaults) to align the text to the right margin x, y designate the upper left corner of the text Alignment: optional. Designates whether text should be left-aligned on x, centered on x or right-aligned on x Use centerformat or rightformat (see defaults) as appropriate Normally set x differently as well Page 5 of 9

6 Instructor s Programming Logic Printing Reports Tips Use a variable (y) to keep track of how far down the page you are Initialize to e.marginbounds.top Increment to start a new line Use fontvariable.height to determine how far to move down to start a new line Height includes the necessary space between lines ev.graphics.drawstring( Volker Gaul,nbFont, Brushes.Blue, 100, 100) y += nbfont.height or y += nbfont.height * 2 Double space There s really no requirement to draw the page from top to bottom, but it sometimes simplifies the logic. Adding Images to the Print Document ev.graphics.drawimage(image.fromfile( filename and path ), x, y) Image.FromFile is a VB function that takes a image filename and returns an image in VB format Path is optional if the image is in the same folder as the executable. If not, you ll have to list the complete path to the file. UNLESS, the folder that contains the image is in the same folder as the executable. Designate folder name, then filename If I m using lots of images, I create an images folder in the folder with the executable. Example: ev.graphics.drawimage(imagefromfile("images\myphoto.jpg"), 100, 100) Page 6 of 9

7 Instructor s Programming Logic Printing Reports Adding Lines to the Print Document You can add lines using underscore characters, but for longer lines, the DrawLine method makes more sense. ev.graphics.drawline(color, x, y, x1, y1) color: Color of the line to draw. Use the Pens collection (Pens.Black) x: x coordinate of the line s starting point (100ths of inches) y: y coordinate of the line s starting point (100ths of inches) x1: x coordinate of the line s ending point (100ths of inches) y1: y coordinate of the line s ending point( 100ths of inches) Note drawing lines is different than drawing rectangles (see below). The DrawLine method wants the starting point and the end point of the line (not the starting point and height/width like the rectangle). One thing I ve discovered: if you are using very precise measurements to layout your page, a line drawn using DrawLine is 1 pixel high (or wide). This is not the same as 1/100 of an inch. This subtle fact caused me a lot of stress trying to get things aligned properly using code. Adding Thicker Lines (Rectangles) to the Print Document To add thicker than 1-point lines to the document, you actually draw filled rectangles You can also use filled rectangles to add shading behind text Draw the shaded rectangle, then add the text ev.graphics.fillrectangle(fillcolor, x, y, w, h) fillcolor: color to fill the rectangle with (use Brushes.color) x: x coordinate of the upper left corner of the rectangle y: y coordinate of the upper left corner of the rectangle w: width of the rectangle h: height of the rectangle Note if you draw a rectangle over a portion of the report that already contains printed objects, the rectangle will cover the existing objects. To get text on (in) a rectangle, generate the rectangle first, then generate the text on top of it. Note that Graphics includes the ability to draw other shapes as well (filled or unfilled). Tip: I ve used white, filled rectangles to erase previously drawn objects on a report. Page 7 of 9

8 Instructor s Programming Logic Printing Reports Creating Multipage Reports One really confusing aspect of generating reports using the Print Document object is how multiple page documents are created. The PrintPage event calls itself to generate subsequent pages of the report. You have to let PrintPage know there are additional pages to print ev.hasmorepages = True The really confusing part is when PrintPage executes this command it calls itself basically starting over from the first command in the event module. Because PrintPage calls itself (actually it calls a clone of itself) you ll need to code a way for the clones to communicate with each other so the clone doesn t print the same page the original did. I use form-level, Boolean variables to do this. Here s a basic example: If Not printingsecondpage Then 'Print the first page stuff here Else 'Print the second page stuff here End If If Not printingsecondpage Then ev.hasmorepages = True 'Let PrintPage know there s another page printingsecondpage = True 'Designate it s time to print 2 nd page Else printingsecondpage = False 'Reset the page flag End If Of course if your document has more pages, it gets even more complicated When there re more than 2 pages, I normally use a page counter variable. I then use the contents of this variable to let PrintPage know which page to create Note that the page flag is reset at the end of the sample code. This is critical. The Print Preview dialog box has a printer icon that allows the user to print directly from the preview dialog. When the user clicks this icon, it calls PrintPage. If you don t reset the page flag (or the page counter), the program will print the last page and only the last page. Page 8 of 9

9 Instructor s Programming Logic Printing Reports Other Print Methods ev.marginbounds.left Designates the x-coordinate of the left edge of the document adjusted by the left margin Usually the same as the left margin ev.marginbounds.right Designates the x-coordinate of the right edge of the document adjusted by the right margin This is NOT the same as the right margin. A right margin set to ½ inch would have a value of 50 (hundredths of an inch). MarginBounds.Right (given a page width of 8 ½ inches) would be 800 ( ) (width right margin) Note these are not part of the Graphics object. Check boxes Create a WingDings font variable Use these character codes in combination with the WingDings font to display checked or unchecked boxes. Dim CHECKEDBOX As String = Chr(254) Dim UNCHECKEDBOX As String = Chr(168) Determining width of a string ev.graphics.measurestring("text to Measure", FStextBold).Width Note you must provide both the text and the font MeasureString returns the width of the string in hundredths of inches. This command returns a value of type Single. Convert to Integer if necessary. Page 9 of 9