Working with the Button Types
Instinctively, you know the role of a ‘button’ control:
• It is a UI element that can be pressed via the mouse or keyboard (with the Enter key or Space key)
if it has the current focus.
• The ButtonBase class serves as a parent for three core-derived types: Button, RepeatButton,
and ToggleButton.
Like any parent class, ButtonBase defines common members for child types. ButtonBase defines the Click event. It
also defines the IsPressed property, which allows you to take a course of action when the derived type has been
pressed but not yet released. In addition, here are some other members of interest for the ButtonBase abstract base
class:
The ClickMode property allows you to specify three different modes of clicking a button. This property can be
assigned any value from the related System.Windows.Controls.ClickMode enumeration:
public enum ClickMode
{
Release,
Press,
Hover
}
The following XAML defines a button that will fire the Click event whenever the mouse cursor is within its bounds.
Although this may not be the most helpful course of action for a typical push button, ‘hover’ mode can be useful
when building custom styles, templates, or animations.
<Button Name = "bntHoverClick" ClickMode = "Hover"
Click = "btnHoverClick_Click"/>
The ToggleButton type (defined in the System.Windows.Controls.Primitives namespace) has by default a UI identical
to the Button type. However, it has the unique ability to hold its pressed state when clicked. To account for this,
ToggleButton provides an IsChecked property that toggles between true and false when the end user clicks on the
UI element. Furthermore, ToggleButton provides two events (Checked and Unchecked), which can be handled to
intercept this state change.
Consider the following XAML:
<!-- A Yes / No toggle button. -->
<ToggleButton Name = "toggleOnOffButton"
Checked = "toggleOnOffButton_Checked"
Unchecked = "toggleOnOffButton_Unchecked" Content="Off!"/>
The event handlers simply change the Content property value:
// C# (VB code would be similar).
protected void toggleOnOffButton_Checked(object sender,
RoutedEventArgs e)
{
toggleOnOffButton.Content = "On!";
}
protected void toggleOnOffButton_Unchecked(object sender,
RoutedEventArgs e)
{
toggleOnOffButton.Content = "Off!";
}
If you would rather have each event route to the same handler, you could consolidate your logic as follows. Note the
use of the IsChecked property.
// C# (VB code would be similar).
protected void toggleOnOffButtonPressed(object sender,
RoutedEventArgs e)
{
if (toggleOnOffButton.IsChecked == false )
toggleOnOffButton.Content = "Off!";
else
toggleOnOffButton.Content = "On!";
}
The next ButtonBase-derived type to point out is the RepeatButton type, also defined within System.Windows.
Controls.Primitives. It supports the ability to continuously fire its Click event when the end user has the widget in a
pressed state. The frequency with which it will fire the Click event depends on the values you assign to the Delay and
Interval properties, both of which are recorded in milliseconds.
In reality, the RepeatButton type, like the ToggleButton type, is not that useful on its own. However, the exposed
behavior is useful when constructing user interfaces.
Consider that the initial release of Silverlight does not supply a ‘spin button’ control. Composing a spin button widget
can be done quite simply in XAML given the functionality of RepeatButton:
<StackPanel>
<!-- The ‘Up’ button. -->
<RepeatButton Height = "25" Width = "25"
Name = "repeatAddValueButton" Delay = "200" Interval = "1"
Click = "repeatAddValueButton_Click"
Content = "+"/>
<!-- Displays the current value. -->
<TextBox Name ="lblCurrentValue" Background = "LightGray"
Height = "30" Width = "25" VerticalContentAlignment = "Center"
HorizontalContentAlignment = "Center" FontSize="15"/>
<!-- The ‘Down’ button. -->
<RepeatButton Height = "25" Width = "25"
Name = "repeatRemoveValueButton" Delay = "200" Interval = "1"
Click = "repeatRemoveValueButton_Click"
Content = "-"/>
</StackPanel>
The Event handlers would simply update the Label’s content with a new value as in the following example:
// C# (VB code would be similar)
public partial class Page : UserControl
{
private int currValue = 0;
public Page()
{
InitializeComponent();
lblCurrentValue.Text = currValue.ToString();
}
protected void repeatAddValueButton_Click(object sender, RoutedEventArgs e)
{
currValue++;
lblCurrentValue.Text = currValue.ToString();
}
protected void repeatRemoveValueButton_Click(object sender, RoutedEventArgs e)
{
currValue--;
lblCurrentValue.Text = currValue.ToString();
}
}
Of course, a production-level spin control would not be embedded directly within a UserControl, but isolated in a
custom control. Furthermore, you would want to add additional bits of functionality to test ranges, fire events, and so
on. Also, you may wish to make use of ‘dependency properties’. You will learn about dependency properties and
custom controls later in the class.
Finally, consider the HyperlinkButton control. This control supports the NavigateUri property, which can be set to
any valid web address. If the user clicks on the link the hosting browser will navigate to the specified page.
<HyperlinkButton Content="Need Training?"
NavigateUri="http://www.intertech.com"/>
Instinctively, you know the role of a ‘button’ control:
• It is a UI element that can be pressed via the mouse or keyboard (with the Enter key or Space key)
if it has the current focus.
• The ButtonBase class serves as a parent for three core-derived types: Button, RepeatButton,
and ToggleButton.
Like any parent class, ButtonBase defines common members for child types. ButtonBase defines the Click event. It
also defines the IsPressed property, which allows you to take a course of action when the derived type has been
pressed but not yet released. In addition, here are some other members of interest for the ButtonBase abstract base
class:
The ClickMode property allows you to specify three different modes of clicking a button. This property can be
assigned any value from the related System.Windows.Controls.ClickMode enumeration:
public enum ClickMode
{
Release,
Press,
Hover
}
The following XAML defines a button that will fire the Click event whenever the mouse cursor is within its bounds.
Although this may not be the most helpful course of action for a typical push button, ‘hover’ mode can be useful
when building custom styles, templates, or animations.
<Button Name = "bntHoverClick" ClickMode = "Hover"
Click = "btnHoverClick_Click"/>
The ToggleButton type (defined in the System.Windows.Controls.Primitives namespace) has by default a UI identical
to the Button type. However, it has the unique ability to hold its pressed state when clicked. To account for this,
ToggleButton provides an IsChecked property that toggles between true and false when the end user clicks on the
UI element. Furthermore, ToggleButton provides two events (Checked and Unchecked), which can be handled to
intercept this state change.
Consider the following XAML:
<!-- A Yes / No toggle button. -->
<ToggleButton Name = "toggleOnOffButton"
Checked = "toggleOnOffButton_Checked"
Unchecked = "toggleOnOffButton_Unchecked" Content="Off!"/>
The event handlers simply change the Content property value:
// C# (VB code would be similar).
protected void toggleOnOffButton_Checked(object sender,
RoutedEventArgs e)
{
toggleOnOffButton.Content = "On!";
}
protected void toggleOnOffButton_Unchecked(object sender,
RoutedEventArgs e)
{
toggleOnOffButton.Content = "Off!";
}
If you would rather have each event route to the same handler, you could consolidate your logic as follows. Note the
use of the IsChecked property.
// C# (VB code would be similar).
protected void toggleOnOffButtonPressed(object sender,
RoutedEventArgs e)
{
if (toggleOnOffButton.IsChecked == false )
toggleOnOffButton.Content = "Off!";
else
toggleOnOffButton.Content = "On!";
}
The next ButtonBase-derived type to point out is the RepeatButton type, also defined within System.Windows.
Controls.Primitives. It supports the ability to continuously fire its Click event when the end user has the widget in a
pressed state. The frequency with which it will fire the Click event depends on the values you assign to the Delay and
Interval properties, both of which are recorded in milliseconds.
In reality, the RepeatButton type, like the ToggleButton type, is not that useful on its own. However, the exposed
behavior is useful when constructing user interfaces.
Consider that the initial release of Silverlight does not supply a ‘spin button’ control. Composing a spin button widget
can be done quite simply in XAML given the functionality of RepeatButton:
<StackPanel>
<!-- The ‘Up’ button. -->
<RepeatButton Height = "25" Width = "25"
Name = "repeatAddValueButton" Delay = "200" Interval = "1"
Click = "repeatAddValueButton_Click"
Content = "+"/>
<!-- Displays the current value. -->
<TextBox Name ="lblCurrentValue" Background = "LightGray"
Height = "30" Width = "25" VerticalContentAlignment = "Center"
HorizontalContentAlignment = "Center" FontSize="15"/>
<!-- The ‘Down’ button. -->
<RepeatButton Height = "25" Width = "25"
Name = "repeatRemoveValueButton" Delay = "200" Interval = "1"
Click = "repeatRemoveValueButton_Click"
Content = "-"/>
</StackPanel>
The Event handlers would simply update the Label’s content with a new value as in the following example:
// C# (VB code would be similar)
public partial class Page : UserControl
{
private int currValue = 0;
public Page()
{
InitializeComponent();
lblCurrentValue.Text = currValue.ToString();
}
protected void repeatAddValueButton_Click(object sender, RoutedEventArgs e)
{
currValue++;
lblCurrentValue.Text = currValue.ToString();
}
protected void repeatRemoveValueButton_Click(object sender, RoutedEventArgs e)
{
currValue--;
lblCurrentValue.Text = currValue.ToString();
}
}
Of course, a production-level spin control would not be embedded directly within a UserControl, but isolated in a
custom control. Furthermore, you would want to add additional bits of functionality to test ranges, fire events, and so
on. Also, you may wish to make use of ‘dependency properties’. You will learn about dependency properties and
custom controls later in the class.
Finally, consider the HyperlinkButton control. This control supports the NavigateUri property, which can be set to
any valid web address. If the user clicks on the link the hosting browser will navigate to the specified page.
<HyperlinkButton Content="Need Training?"
NavigateUri="http://www.intertech.com"/>
Button Types
Table of Contents
Copyright (c) 2008. Intertech, Inc. All Rights Reserved. This information is to be used exclusively as an
online learning aid. Any attempts to copy, reproduce, or use for training is strictly prohibited.
online learning aid. Any attempts to copy, reproduce, or use for training is strictly prohibited.
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