Your First Printing Application

We just saw how the printing process works in the .NET Framework. Now let's talk about how to write your first simple printing application. In this application we will send the text "Hello Printer!" to the printer from a Windows application. To create this application, follow the simple steps described here.

Using Visual Studio .NET, create a Windows application project named HelloPrinterSamp, as shown in Figure 11.6.

Figure 11.6. Creating a Windows application

After we create the project, we add the following line to it:

using System.Drawing.Printing;

Then we add controls for a label, a combo box, and a button to the form. We change the Text and Name properties of the form and these controls. (See the online source code for more details.) The final form should look like Figure 11.7.

Figure 11.7. Your first printing application

When you run this application, the combo box will display the available printers on your machine. You can select any printer from this list, and when you click the Hello Printer button, it will print "Hello Printer!" on your printer.

We load the available printers on the form's load event handler. The PrinterSettings.InstalledPrinters property returns the installed printers on a machine. PrinterSettings.InstalledPrinters.Count returns the total number of printers. In Listing 11.2 we check if printers are installed on the machine, read them, and add them to the printer list combo box.

Listing 11.2 Getting all installed printers

private void Form1_Load(object sender, System.EventArgs e) { // See if any printers are installed if( PrinterSettings.InstalledPrinters.Count <= 0) { MessageBox.Show("Printer not found!"); return; } // Get all available printers and add them to the // combo box foreach(String printer in PrinterSettings.InstalledPrinters) { printersList.Items.Add(printer.ToString()); } }

The next step is to add code to the Hello Printer button click event handler (see Listing 11.3). This code is responsible for printing. We create a PrintDocument object and set the PrintDocument.PrinterSettings. PrinterName property to the printer selected from the printer list combo box. Then we add a print-page event handler and call the PrintDocument.Print method, which prints the document.

Listing 11.3 The Hello Printer button click event handler

private void HelloPrinterBtn_Click(object sender, System.EventArgs e) { // Create a PrintDocument object PrintDocument pd = new PrintDocument(); // Set PrinterName as the selected printer // in the printers list pd.PrinterSettings.PrinterName = printersList.SelectedItem.ToString(); // Add PrintPage event handler pd.PrintPage += new PrintPageEventHandler(pd_PrintPage); // Print the document pd.Print(); }

The last step is to add the print-page event handler code (see Listing 11.4). This code is responsible for creating a Graphics object for the printer. It calls the DrawString method, which is responsible for drawing text. First we create a Graphics object from PrintPageEventArgs.Graphics. Then we create Font and SolidBrush objects and call DrawString to draw some text on the printer. The DrawString method takes a string that represents the text to be drawn; the font; a brush; and a layout rectangle that represents the starting point, width, and height of a rectangle for the text.

Note

See Chapter 3 for more detail on the DrawString method. And for more about solid brushes and fonts, see Chapters 4 and 5, respectively.

Listing 11.4 The print-page event handler

// The PrintPage event handler public void pd_PrintPage(object sender, PrintPageEventArgs ev) { // Get the Graphics object Graphics g = ev.Graphics; // Create a font Arial with size 16 Font font = new Font("Arial", 16); // Create a solid brush with black color SolidBrush brush = new SolidBrush(Color.Black); // Draw "Hello Printer!" g.DrawString("Hello Printer!", font, brush, new Rectangle(20, 20, 200, 100)); }

Now you can run the application, select a printer from the list, and click the Hello Printer button. You should see "Hello Printer!" on your printed page.