Printing Text in GDI+ using VB.NET
In this article I will explain about Printing Text in GDI+.
So far we have printed simple text and graphics items from the program itself. How about reading a text file and printing it from our program? We can make the editor open a text file and add print functionality to print the text file. In this section we will read a text file and print it.
As usual, we create a Windows application and add a reference to the System.Drawing.Printing namespace. We then add a text box and four buttons to the form. We also change the Name and Text properties of the buttons controls. The final form looks like Figure 11.12. As you might guess, the Browse Text File button allows us to browse for text files.
FIGURE 11.12: The form with text file printing options
The code for the Browse Text File button is given in Listing 11.21. This button allows you to browse a file and adds the selected file name to the text box. Clicking the Print Text File button prints the selected text file. We use an OpenFileDialog object to open a text file and set textBox1.Text as the selected file name. The functionality of the Print Text and Print Events buttons is obvious.
LISTING 11.21: The Browse Text File button click event handler
Private Sub BrowseBtn_Click(ByVal sender As Object, ByVal e As System.EventArgs)
'Create an OpenFileDialog object
Dim fdlg As New OpenFileDialog()
'Set its properties
fdlg.Title = "C# Corner Open File Dialog"
fdlf.InitialDirectory = "C:\"
fdlg.Filter = "Text files (*.txt | .txt | All files (*.*) | *.*"
fdlg.FilterIndex = 2
fdlg.RestoreDirectoty = True
'Show dialog and set the selected file name
'as the text of the text box
If fldg.ShowDialog() = DialogResult.OK Then
textBox1.Text = fdlg.FileName
Now let's add code for the Print Text File button click. First we add tow private variable to the application as follows:
Private verdana10Font As Font
Private reader As StreamReader
Then we proceed as shown in Listing 11.22. The code is pretty simple. First we make sure that the user has selected a file name. Then we create a StreamReader object and read the file by passing the file name as the only argument. Next we create a font with font family Verdana and size 10. After that we create a PrintDocument object, and a PrintPage event handler, and call the Print method. The rest is done by the PrintPage event handler.
Note: The StreamReader class is defined in the System.IO namespace.
LISTING 11.22: The Print Text File button click event handler
Private Sub PrintTextFile_Click(ByVal sender As Object, ByVal e As System.EventArgs)
'Get the file name
Dim filename As String = textBox1.Text.TosTring()
'check if it's not empty
If filename.Equals(String.Empty) Then
MessageBox.Show("Enter a valid file name")
'Create a StreamReader object
reader = New StreamReader(filename)
'Create a Verdana font with size 10
verdana10Font = New Font("Verdana", 10)
'Create a PrintDocument object
Dim pd As New PrintDocument()
'Add PrintPage event handler
pd.PrintPage += New PrintPageEventHandler(Me.PrintTextFileHandler)
'Call Print Method
'Close the reader
If reader IsNot Nothing Then
The code for the PrintPage event handler PrintTextFileHandler is given in Listing 11.23. Here we read one line at a time from the text file, using the StreamReader.ReadLine method, and call DrawString, which prints each line until we reach the end of the file. To give the text a defined size, we use the verdana10Font.GetHegiht method.
LISTING 11.23: Adding a print event handler
Private Sub PrintTextFileHandler(ByVal sender As Object, ByVal ppeArgs As PrintPageEventArgs)
'Get the Graphics object
Dim g As Graphics = ppeArgs.Graphics
Dim linesPerPage As Single = 0
Dim yPos As Single = 0
Dim count As Integer = 0
'Read margins from PrintPageEventArgs
Dim leftMargin As Single = ppeArgs.MarginBounds.Left
Dim topMargin As Single = ppeArgs.MarginBounds.TOP
Dim line As String = Nothing
'Calculate the lines per page on the basis of the height of the page and the height of the font
linesPerPage = ppeArgs.MarginBounds.Height
'Now read lines one by one, using StreamReader
While count < linesPerPage AndAlso ((InlineAssignHelper(line, reader.REadLine())) IsNot Nothing)
'Calculate the starting position
yPos = topMargin + (count * verdana10Font.GetHeight(g))
g.DrawString(line, verdana10Font, Brushes.Black, leftMargin, yPose, New StringFormat())
'Move to next line
count += 1
'If PrintPageEventArgs has more pages to print
If line IsNot Nothing Then
ppeArgs.HasMorePages = True
ppeArgs.HasMorePages = False
You should be able to add code for the Print Text and Print Events buttons yourself. Their functionality should be obvious.
Now run the application, browse a text file, and hit the Print Text File button, and you should be all set.
Note: Using the same method, you can easily add printing functionality to the GDI+ editor. You can add a menu item called Print to the editor that will print an opened text file.
Hope the article would have helped you in understanding Printing Text in GDI+. Read other articles on GDI+ on the website.