wpf binding when using datatemplate - wpf

Question

ok currently i have this piece of code:
<TabItem Style="{DynamicResource MyStyle" x:Name="TabCustomers" Padding="0,1,4,1"
Header={Binding Path=customersHeader}/>
Now i want to add an icon there so I do (by removing the header above):
<TabItem.Header>
<StackPanel Orientation="Horizontal">
<Image Stretch="UniformToFill" Source="{StaticResource customers}"/>
<TextBlock x:Key="textblock" Margin="4,0,0,0"
Text="{Binding Path=customersHeader}"/>
</StackPanel>
</TabItem.Header>
So far it's ok.
I would like to generalize this using a datatemplate. I assume i have to do this in my resource dictionary:
<DataTemplate x:Key="TabItemCustomersTemplate" DataType="{x:Type TabItem}">
<StackPanel Orientation="Horizontal">
<Image Stretch="UniformToFill" Source="{StaticResource customers}"/>
<TextBlock x:Key="textblock" Margin="4,0,0,0"
Text="{Binding Path=customersHeader}"/>
</StackPanel>
</DataTemplate>
and change this in my tabitem declaration:
<TabItem ... HeaderTemplate="{StaticResource TabItemCustomersTemplate}".../>
So i run into the following issues and questions:
1) binding doesnt work, why?
2) how can i access textblock from c#?
3) how can i generalize this so i dont have to copy this over and over again for different tab items (or other controls for the matter) so that i can pass my own text and image source each time? For example you might use this to create an image button and if you have 20 buttons the code becomes messy.
Any ideas?
Thank you.

Answer 1

if you template the header in a
tabitem, you do not need to set the
data type of the template. the
header is a property of the tab
item, it is actually a property of
type object, you can put anything in
there.
try removing the DataType="{x:Type
TabItem}" and see if it works.
you should not need to access the
textblock from c#, you should make
do with the binding system. place a
custom object in your header. then
bind this object to your textblock
then adjust the object and it will
manipulate the textblock. getting at
an element is always hard if it is
contained in a data template. you
should not need to. if you find
yourself walking the visual tree to
find a visual element you are doing
things the hard way
you can generalise this by following
suggestion 2, using a custom object,
removing the x:Key of your data
template and setting its DataType to
be the type of your custom object.
then wherever your custom object
appears you will get it data
templated properly

Answer 2

Try this, This is working for me
<Window.Resources>
<!-- <BitmapImage x:Key="customers" UriSource="einstein.jpg"/>-->
<DataTemplate x:Key="TabItemCustomersTemplate">
<StackPanel Orientation="Horizontal">
<Image Stretch="UniformToFill" Source="{Binding Path=Customers}"/>
<TextBlock Margin="4,0,0,0" x:Name="txt" Text="{Binding Path=CustomersHeader}"/>
</StackPanel>
</DataTemplate>
</Window.Resources>
<Grid>
<TabControl Name="mytabcontrol">
<TabItem x:Name="TabCustomers" Padding="0,1,4,1" Header="{Binding}" HeaderTemplate="{StaticResource TabItemCustomersTemplate}">
<Label Content="myContent" Background="Red"/>
</TabItem>
</TabControl>
</Grid>
in code behind
public partial class Window1 : Window
{
public Window1()
{
InitializeComponent();
var lst = new List<People>();
lst.Add(new People() { CustomersHeader = "My Customer" });
this.DataContext = lst;
}
}
public class People
{
public string CustomersHeader { get; set; }
public BitmapImage Customers { get; set; }
}
Further you can find your textblock in code behind using this
TabPanel tabPanel = GetVisualChild<TabPanel>(mytabcontrol);
if (tabPanel != null)
{
foreach (UIElement element in tabPanel.Children)
{
TabItem tabItem = element as TabItem;
var image = FindNameFromHeaderTemplate<TextBlock>(tabItem, "txt");
}
}
public static T FindNameFromHeaderTemplate<T>(TabItem tabItem, String name) where T : UIElement
{
if (tabItem == null)
{
throw new ArgumentNullException("container");
}
if (tabItem.HeaderTemplate == null)
{
return null;
}
ContentPresenter contentPresenter = GetVisualChild<ContentPresenter>(tabItem);
if (contentPresenter == null)
{
return null;
}
T element = tabItem.HeaderTemplate.FindName(name, contentPresenter) as T;
return element;
}
public static T GetVisualChild<T>(Visual referenceVisual) where T : Visual
{
Visual child = null;
for (Int32 i = 0; i < VisualTreeHelper.GetChildrenCount(referenceVisual); i++)
{
child = VisualTreeHelper.GetChild(referenceVisual, i) as Visual;
if (child != null && child.GetType() == typeof(T))
{
break;
}
else if (child != null)
{
child = GetVisualChild<T>(child);
if (child != null && child.GetType() == typeof(T))
{
break;
}
}
}
return child as T;
}