This topic has not yet been rated - Rate this topic

DataTemplate.LoadContent Method

Silverlight

Creates the UIElement objects in the DataTemplate.

Namespace: System.Windows
Assembly: System.Windows (in System.Windows.dll)

Copy

public DependencyObject LoadContent()

Return Value

Type: System.Windows.DependencyObject
The root UIElement of the DataTemplate.

Remarks

When you call LoadContent, the UIElement objects in the DataTemplate are created, and you can add them to the visual tree of another UIElement.

Examples

The following examples demonstrate using the LoadContent method to change the appearance of a Border at run time. The example creates a ListBox that contains the numbers 1 through 10. When the user selects an item in the ListBox, the Border displays the selected number. If the user selects an even number, the number is red and has a green circle around it. If the user selects an odd number, the number is blue and has a purple square around it.

Run this sample

XAML

Copy


<StackPanel Background="White" Name="rootStackPanel">

  <StackPanel.Resources>
    <DataTemplate x:Key="oddNumberTemplate">
      <Grid>
        <Rectangle Stroke="Purple" StrokeThickness="4" />
        <TextBlock HorizontalAlignment="Center" 
                   VerticalAlignment="Center" 
                   FontSize="24" Foreground="Blue" 
                   FontWeight="Bold"/>
      </Grid>
    </DataTemplate>


    <DataTemplate x:Key="evenNumberTemplate">
      <Grid>
        <Ellipse Stroke="Green" StrokeThickness="4"/>
        <TextBlock HorizontalAlignment="Center" 
                   VerticalAlignment="Center" 
                   FontSize="24" Foreground="Red" 
                   FontWeight="Bold"  />
      </Grid>
    </DataTemplate>
  </StackPanel.Resources>


  <Border Name="selectedItemDisplay"
          Width="50" Height="50"/>

  <ListBox Name="numberList" SelectionChanged="ListBox_SelectionChanged">
    <ListBoxItem Content="1"/>
    <ListBoxItem Content="2"/>
    <ListBoxItem Content="3"/>
    <ListBoxItem Content="4"/>
    <ListBoxItem Content="5"/>
    <ListBoxItem Content="6"/>
    <ListBoxItem Content="7"/>
    <ListBoxItem Content="8"/>
    <ListBoxItem Content="9"/>
    <ListBoxItem Content="10"/>
  </ListBox>
</StackPanel>

Copy


private void ListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
    ListBoxItem lbi = ((sender as ListBox).SelectedItem as ListBoxItem);
    SelectDataTemplate(lbi.Content);

}

private void SelectDataTemplate(object value)
{
    string numberStr = value as string;

    if (numberStr != null)
    {
        int num;

        try
        {
            num = Convert.ToInt32(numberStr);
        }
        catch
        {
            return;
        }

        DataTemplate template;

        // Select one of the DataTemplate objects, based on the 
        // value of the selected item in the ComboBox.
        if (num % 2 != 0)
        {
            template = rootStackPanel.Resources["oddNumberTemplate"] as DataTemplate;
        }
        else
        {
            template = rootStackPanel.Resources["evenNumberTemplate"] as DataTemplate;
        }

        selectedItemDisplay.Child = template.LoadContent() as UIElement;
        TextBlock tb = FindVisualChild<TextBlock>(selectedItemDisplay);
        tb.Text = numberStr;

    }
}

private childItem FindVisualChild<childItem>(DependencyObject obj)
    where childItem : DependencyObject
{

    for (int i = 0; i < VisualTreeHelper.GetChildrenCount(obj); i++)
    {

        DependencyObject child = VisualTreeHelper.GetChild(obj, i);

        if (child != null && child is childItem)
            return (childItem)child;
        else
        {
            childItem childOfChild = FindVisualChild<childItem>(child);
            if (childOfChild != null)
                return childOfChild;
        }
    }

    return null;
}

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

Reference

DataTemplate Class

System.Windows Namespace

Did you find this helpful? Yes No

Not accurate

Not enough depth

Need more code examples

(1500 characters remaining)

Community Content Add

FAQ

The FindVisualChild provided above is crappy, I rewrote it

I can say that the one who wrote it is not so familiar with VB, since && operator is AndAlso in VB, not And.
I was only reviewing the FindVisualChild function so I have no clue what about the rest.

<Extension()> _
Public Function GetVisualDescendant(Of TChild As DependencyObject)(ByVal reference As DependencyObject) As TChild
    For i = 0 To VisualTreeHelper.GetChildrenCount(reference) - 1
        Dim child = VisualTreeHelper.GetChild(reference, i)
        If child Is Nothing Then
            Continue For
        ElseIf Type.Equals(child.GetType, GetType(TChild)) Then
            Return child
        Else
            Return GetVisualDescendant(Of TChild)(child)
        End If
    Next
Return Nothing
End Function

History

12/10/2009
Shimmy Weitzhandler

12/10/2009
Shimmy Weitzhandler

And just in case I also wrote a GetVisualAncestor ex. method:

<Extension()> _
Public Function GetVisualAncestor(Of TParent As DependencyObject)(ByVal reference As DependencyObject) As TParent
    Dim parent = VisualTreeHelper.GetParent(reference)
    While parent IsNot Nothing AndAlso Not Type.Equals(parent.GetType, GetType(TParent))
        parent = GetVisualAncestor(Of TParent)(parent)
    End While
    Return parent
End Function

History

12/10/2009
Shimmy Weitzhandler