C# 4 and .NET 4

OC34 ❘ ChaPTer 48 GrAphics with Gdi+
your selected font is. It is the same for all lines of text so there is no point storing the height separately for
each one; you store it once, in the Form1.lineHeight field. As for the position, well, in this case, the x
coordinate is just equal to the margin, and the y coordinate is easily calculated here:
margin + lineHeight*(however many lines are above this one)
If you had been trying to display and manipulate, say, individual words instead of complete lines, then
the x position of each word would have to be calculated using the widths of all the previous words on that
line of text, but the intent is to keep it simple here, which is why you are treating each line of text as one
single item.
Let’s turn to the main menu now. This part of the application is more the realm of Windows Forms (see
Chapter 39) than of GDI+. Add the menu options using the design view in Visual Studio 2010, but rename
them menuFile, menuFileOpen, and menuFileExit. Next, add event handlers for the File Open and File
Exit menu options using the Visual Studio 2010 properties window. The event handlers have their Visual
Studio 2010-generated names of menuFileOpen_Click() and menuFileExit_Click().
Add some extra initialization code in the Form1() constructor:
public Form1()
{
InitializeComponent();
CreateFonts();
fileOpenDialog.FileOk += delegate { LoadFile(fileOpenDialog.FileName); };
fileOpenDialog.Filter =
"Text files (*.txt)|*.txt|C# source files (*.cs)|*.cs";
}
code download CapsEditor.sln
You add the event handler here for instances when the user clicks OK in the File Open dialog box. You have
also set the filter for the Open File dialog box, so that you can load text files only. The example in this
case only uses .txt files, in addition to the C# source files, so you can use the application to examine the
source code for the samples.
CreateFonts() is a helper method that sorts out the fonts you intend to use:
private void CreateFonts()
{
mainFont = new Font("Arial", 10);
lineHeight = (uint)mainFont.Height;
emptyDocumentFont = new Font("Verdana", 13, FontStyle.Bold);
}
The actual definitions of the handlers are pretty standard:
protected void menuFileOpen_Click(object sender, EventArgs e)
{
fileOpenDialog.ShowDialog();
}
protected void menuFileExit_Click(object sender, EventArgs e)
{
Close();
}
Next, take a look at the LoadFile() method. It handles the opening and reading of a file (as well as
ensuring a Paint event is raised to force a repaint with the new file):
private void LoadFile(string FileName)
{
StreamReader sr = new StreamReader(FileName);
string nextLine;
documentLines.Clear();
www.it-ebooks.info