WPF FAQ - TabControl

The TabItems have a Visibility property which can be set to Collapsed (no space will be reserved for this tab) or Hidden (not rendered, but space will be reserved for this tab).

[XAML]
 
        <TabControl x:Name='tabControl1'>
            <TabItem Header='Tab1'></TabItem>
            <TabItem Header='Tab2' Visibility='Hidden'></TabItem>
            <TabItem Header='Tab3' Visibility='Collapsed'></TabItem>
            <TabItem Header='Tab4'></TabItem>
        </TabControl>  

This Code Project article provides you such an implementation:

An Extended WPF TabControl

Here is a custom style that changes the look and feel of the tabs (TabItems) in the corresponding window.

[XAML]

<Style TargetType='TabItem'>
  <Setter Property='BorderThickness' Value='3'/>
  <Setter Property='BorderBrush' Value='Red'/>
  <Setter Property='Background' Value='LightBlue'/>
  <Setter Property='VerticalContentAlignment' Value='Center'/>
  <Setter Property='HorizontalContentAlignment' Value='Center'/>
  <Setter Property='Template'>
    <Setter.Value>
      <ControlTemplate TargetType='{x:Type TabItem}'>
        <Border>
          <Grid>
            <Grid>
              <Border CornerRadius='3,3,0,0' Background='{TemplateBinding Background}' 
                   BorderBrush='{TemplateBinding BorderBrush}' 
                   BorderThickness='{TemplateBinding BorderThickness}'/>
            </Grid>
            <Border BorderThickness='{TemplateBinding BorderThickness}' 
                 Padding='{TemplateBinding Padding}'>
              <ContentPresenter ContentSource='Header' 
                 HorizontalAlignment='{TemplateBinding HorizontalContentAlignment}' 
                 VerticalAlignment='{TemplateBinding VerticalContentAlignment}'/>
            </Border>
          </Grid>
        </Border>
      </ControlTemplate>
    </Setter.Value>
  </Setter>
</Style>

This is how the tabs look with the above style applied on them:

Set the ‘TabStripPlacement’ enum property to ‘Bottom’. The possible enum values of this property are Left, Top, Right and Bottom.

Unfortunately, WPF doesn’t provide a straight forward way of validating a tab page’s content before switching to a new tab, in the first version. One workaround is to listen to the TabItem’s PreviewLostKeyboardFocus event and mark it as Handled as shown below.

[C#]
        public TabValidation()
        {
            InitializeComponent();

            foreach (TabItem item in tabControl1.Items)
            {
                item.PreviewLostKeyboardFocus += new KeyboardFocusChangedEventHandler(item_PreviewLostKeyboardFocus);
            }
        }

        void item_PreviewLostKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e)
        {
            // sender is the TabItem.
            if (this.ValidateTab() == false)
                e.Handled = true;
        }