Common dialog boxes for printing

The C# Column - Yashawant Kanetkar

In this article we will see how to print a multi-page document using common dialog boxes of printing such as PrintPreview, Print and PageSetup. For these dialog boxes .NET has provided the PrintPreviewDialog control, the PrintDialog control and the PageSetupDialog control.

To illustrate the use of these dialog boxes let us create a Windows Form application called prntdlg. We also added a widely used OpenFileDialog control to the form along with two textboxes—filename and mytext-and five buttons—a ‘Browse’ button named browse, an ‘Open’ button named open, a ‘PageSetup’ button named pgsetup, a ‘Print Preview’ button named preview, and a ‘Print’ button named print. Next we added five components to the component tray and changed their names as shown below:

The UI of the prntdlg application is shown in the following figure.

Next we have added Click event handlers for all the five buttons. The handler for the browse button is given below.

private void browse_Click (object sender,
System.EventArgs e)
{
myopendlg.Filter = "Text Files ( *.txt ) | *.txt" ;
myopendlg.ShowDialog( ) ;
if (myopendlg.FileName != "" )
filename.Text = myopendlg.FileName ;
}

The ‘Browse’ button lets the user select a file for printing. The user selects the file from the standard Open File dialog box. We have displayed the dialog box in this handler. The selected file name is displayed in the text box.

As soon as the user clicks the ‘Open’ button the following handler gets called:

private void open_Click ( object sender,
System.EventArgs e )
{
StreamReader reader = new StreamReader
( filename.Text ) ;
mytext.Text = reader.ReadToEnd( ) ;
reader.Close( ) ;
}

Here we have read the file contents with the help of an object of the StreamReader class and displayed them on the mytext textbox. Now if the user wants to change the page settings he needs to click the ‘Page Settings’ button. On doing so the following handler gets called:

private void pgsetup_Click ( object sender,
System.EventArgs e )
{
try
{
mypgsdlg.PageSettings = ps ;
mypgsdlg.ShowDialog( ) ;
}
catch ( Exception ex )
{
MessageBox.Show ( ex.Message ) ;
}
}

We have added an object referred to by ps of the PageSettings class as a data member of the form class as follows:

PageSettings ps = new PageSettings( ) ;

The zero-argument constructor of this class creates an object of the PageSetting class for the default printer. The default constructor initialises all fields to their default values. Next we have set the PageSettings property of the PageSetupDialog class to ps. Then we have displayed the Page Setup Dialog box using the ShowDialog( ) method.

The user can also preview the page to be printed by clicking on the ‘Print Preview’ button. On doing so the following handler gets called:

private void preview_Click ( object sender,
System.EventArgs e )
{
try
{
str = mytext.Text ;
mypdoc.DefaultPageSettings = ps ;
mypreviewdlg.Document = mypdoc ;
mypreviewdlg.ShowDialog( ) ;
}
catch ( Exception ex )
{
MessageBox.Show ( ex.Message ) ;
}
}

Here first we have collected the string in mytext textbox in str. We have added str of type string as a data member of the form class. Next we set the DefaultPageSettings property of the PrintDocument class to ps. Then we set the Document property of the PrintPreviewDialog class to mypdoc, which specifies the document to be previewed. Next we have displayed the dialog using the ShowDialog( ) method. The PrintPreviewDialog is shown in the following figure:

On clicking the ‘Print’ button the following handler gets called.

private void print_Click ( object sender,
System.EventArgs e )
{
try
{
mypdoc.DefaultPageSettings = ps ;
str = mytext.Text ;
myprintdlg.Document = mypdoc ;
if (myprintdlg.ShowDialog( ) == DialogResult.OK)
mypdoc.Print( ) ;
}
catch ( Exception ex )
{
MessageBox.Show ( ex.Message ) ;
}
}

Here we have first set the DefaultPageSettings property of the PrintDocument class to ps. Next we have collected the text of mytext textbox, which is to be printed in str. The document to be printed is then set to the Document property of the PrintDialog class. Next we displayed the PrintDialog box using the ShowDialog( ) method and if the result happens to be DialogResult.OK, i.e if the user clicks OK, we call the Print( ) method of the PrintDocument class.

On calling the Print( ) method the following handlers get invoked:

private void mypdoc_BeginPrint ( object sender,
System.Drawing.Printing.PrintEventArgs e )
{
f = new Font ( "Arial", 12 ) ;
b = new SolidBrush ( Color.Black ) ;
strformat.Trimming = StringTrimming.Word ;
}
private void mypdoc_PrintPage ( object sender,
System.Drawing.Printing.PrintPageEventArgs e )
{
RectangleF myrect = new RectangleF
(e.MarginBounds.Left, e.MarginBounds.Top,
e.MarginBounds.Width, e.MarginBounds.Height ) ;
SizeF sz = new SizeF ( e.MarginBounds.Width,
e.MarginBounds.Height - f.GetHeight(e.Graphics ) ) ;
e.Graphics.MeasureString ( str, f, sz, strformat,
out chars, out lines ) ;
printstr = str.Substring ( 0, chars ) ;
e.Graphics.DrawString ( printstr, f, b, myrect,
strformat ) ;
if ( str.Length > chars )
{
str = str.Substring ( chars ) ;
e.HasMorePages = true ;
}
else
e.HasMorePages = false ;
}

The code written in this handler takes care of multiple pages being printed as well as word wrapping.

Yashavant Kanetkar, one of the first Express Computer columnists, is an established software expert, speaker and author with several best-sellers to his credit, including titles like “Let Us C” and the “Fundas” series. Contact him at kanet@nagpur.dot.net.in