GtkSharp: Labels


Labels are used a lot in Gtk#, and are relatively simple. Labels emit no events as they do not have an associated X window. If you need to catch events, or do clipping, place it inside a EventBox widget or a Button widget.

[Image:labels.png]

To create a new label, use:

Label label1 = new Label(text);

The sole argument is the string you wish the label to display. To change the label's text after creation, use its Text property.

The space needed for the new string will be automatically adjusted if needed. You can produce multi-line labels by putting line breaks in the label string and setting the LineWrap property to true.

The label text can be aligned/justified using the Justify property, which takes a Gtk.Justify enumeration value: Left, Right, Center, or Fill.

If you want your label underlined, then you can set a pattern on the label:

label1.Pattern = pattern;

The pattern argument indicates how the underlining should look. It consists of a string of underscore and space characters. An underscore indicates that the corresponding character in the label should be underlined. For example, the string "__ __" would underline the first two characters and eight and ninth characters.

If you simply want to have an underlined accelerator ("mnemonic") in your label, you should create the Label with LabelWithMnemonic() or use the TextWithMnemonic property, not the Pattern property.

Below is a short example to illustrate these functions. This example makes use of the Frame widget to better demonstrate the label styles. You can ignore this for now as the Frame widget is explained later on.

// label.cs - Gtk# Tutorial example
//
// Author: Alejandro Sánchez Acosta &li;raciel@es.gnu.org>
//         Cesar Octavio Lopez Nataren &li;cesar@ciencias.unam.mx>
//
// (c) 2002 Alejandro Sánchez Acosta
 
namespace GtkSharpTutorial {
 
        using Gtk;
 
        using System;
        using System.Drawing;
 
        public class label
        {
 
                static void delete_event (object obj, DeleteEventArgs args)
                {
                        Application.Quit();
                }
 
                static void exitbutton_event (object obj, EventArgs args)
                {
                        Application.Quit();
                }
 
                public static void Main (string[] args)
                {
 
                        Widget widget;
                        Window window;
                        HBox hbox;
                        VBox vbox;
                        Frame frame;
                        Label label;
 
                        Application.Init ();   
 
 
                        window = new Window ("Label sample");
 
                        window.DeleteEvent += delete_event;
 
                        window.Title = "Label";
 
                        hbox = new HBox (false, 5);
                        vbox = new VBox (false, 5);
 
                        window.Add (hbox);
                        hbox.PackStart (vbox, false, false, 0);
 
                        window.BorderWidth = 5;
 
                        frame = new Frame ("Normal Label");
                        label = new Label ("This is a normal label");
 
                        frame.Add (label);
                        vbox.PackStart (frame, false, false, 0);
 
                        frame = new Frame ("Multiline Label");
                        label = new Label ("This is a Multi-line label\nSecond Line\nThird Line");
 
                        frame.Add (label);
                        vbox.PackStart (frame, false, false, 0);
 
                        frame = new Frame ("Left Justified Label");
                        label = new Label ("This is a Left-Justified\n" + "Multi-line label.\n" + "Third      line");
                        label.Justify = Justification.Left;
 
                        frame.Add (label);
                        vbox.PackStart (frame, false, false, 0);
 
                        frame = new Frame ("Right Justified Label");                    
                        label = new Label ("This is a Right Justified\nMulti-line label.\n" + "Fourth Line, (j/k)");
                        label.Justify = Justification.Right;
                        frame.Add (label);
                        vbox.PackStart (frame, false, false, 0);
 
                        vbox = new VBox (false, 5);
                        hbox.PackStart(vbox, false, false, 0);
 
                        frame = new Frame ("Line wrapped Label");
                        label = new Label ("This is an example of a line-wrapped label.  It " +
                         "should not be taking up the entire             " /* big space to test spacing */ +
                         "width allocated to it, but automatically " +
                         "wraps the words to fit.  " +
                         "The time has come, for all good men, to come to " +
                         "the aid of their party.  " +
                         "The sixth sheik's six sheep's sick.\n" +
                         "     It supports multiple paragraphs correctly, " +
                         "and  correctly   adds " +
                         "many          extra  spaces. ");
 
                        label.LineWrap = true;
 
                        frame.Add (label);
                        vbox.PackStart(frame, false, false, 0);
 
                        frame = new Frame ("Filled wrapped label");
                        label = new Label ("This is an example of a line-wrapped, filled label.  " +
                         "It should be taking " +
                         "up the entire              width allocated to it.  " +
                         "Here is a sentence to prove " +
                         "my point.  Here is another sentence. " +
                         "Here comes the sun, do de do de do.\n" +
                         "    This is a new paragraph.\n" +
                         "    This is another newer, longer, better " +
                         "paragraph.  It is coming to an end, "+
                                           "unfortunately.");
 
                        label.Justify = Justification.Fill;
                        label.Wrap = true;
                        frame.Add (label);
                        vbox.PackStart (frame, false, false, 0);
 
 
                        frame = new Frame ("Underlined label");
 
                        label = new Label ("This label is underlined!\n" + "This one is underlined in quite a funky fastion");
 
                        label.Justify = Justification.Left;
                        label.Pattern = "_________________________ _ _________ _ ______     __ _______ ___";
 
                        frame.Add (label);
                        vbox.PackStart (frame, false, false, 0);
 
                        window.ShowAll ();
 
                        Application.Run ();
                }
        }
}