How to access a specific item in a Listbox with DataTemplate?
Solution 1
Thank you for your help guys!! Finally i got it. Solved the problem with the VisualTreeHelper. What a great function ^^
private void ContactListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
if (ContactListBox.SelectedIndex == -1)
return;
currentSelectedListBoxItem = this.ContactListBox.ItemContainerGenerator.ContainerFromIndex(ContactListBox.SelectedIndex) as ListBoxItem;
if (currentSelectedListBoxItem == null)
return;
// Iterate whole listbox tree and search for this items
TextBox nameBox = helperClass.FindDescendant<TextBox>(currentSelectedListBoxItem);
TextBlock nameBlock = helperClass.FindDescendant<TextBlock>(currentSelectedListBoxItem);
helperFunction
public T FindDescendant<T>(DependencyObject obj) where T : DependencyObject
{
// Check if this object is the specified type
if (obj is T)
return obj as T;
// Check for children
int childrenCount = VisualTreeHelper.GetChildrenCount(obj);
if (childrenCount < 1)
return null;
// First check all the children
for (int i = 0; i < childrenCount; i++)
{
DependencyObject child = VisualTreeHelper.GetChild(obj, i);
if (child is T)
return child as T;
}
// Then check the childrens children
for (int i = 0; i < childrenCount; i++)
{
DependencyObject child = FindDescendant<T>(VisualTreeHelper.GetChild(obj, i));
if (child != null && child is T)
return child as T;
}
return null;
}
Solution 2
With this edited function you can also search for control by name (its converted from VB.NET):
public T FindDescendantByName<T>(DependencyObject obj, string objname) where T : DependencyObject
{
string controlneve = "";
Type tyype = obj.GetType();
if (tyype.GetProperty("Name") != null) {
PropertyInfo prop = tyype.GetProperty("Name");
controlneve = prop.GetValue((object)obj, null);
} else {
return null;
}
if (obj is T && objname.ToString().ToLower() == controlneve.ToString().ToLower()) {
return obj as T;
}
// Check for children
int childrenCount = VisualTreeHelper.GetChildrenCount(obj);
if (childrenCount < 1)
return null;
// First check all the children
for (int i = 0; i <= childrenCount - 1; i++) {
DependencyObject child = VisualTreeHelper.GetChild(obj, i);
if (child is T && objname.ToString().ToLower() == controlneve.ToString().ToLower()) {
return child as T;
}
}
// Then check the childrens children
for (int i = 0; i <= childrenCount - 1; i++) {
string checkobjname = objname;
DependencyObject child = FindDescendantByName<T>(VisualTreeHelper.GetChild(obj, i), objname);
if (child != null && child is T && objname.ToString().ToLower() == checkobjname.ToString().ToLower()) {
return child as T;
}
}
return null;
}
Solution 3
private void ContactListBox_SelectionChanged
(object sender, SelectionChangedEventArgs e)
{
if (e.AddedItems.Count == 1)
{
var container = (FrameworkElement)ContactListBox.ItemContainerGenerator.
ContainerFromItem(e.AddedItems[0]);
StackPanel sp = container.FindVisualChild<StackPanel>();
TextBox tbName = (TextBox) sp.FindName("tbName");
TextBlock lblName = (TextBlock)sp.FindName("lblName");
TextBlock lblNumber = (TextBlock)sp.FindName("lblNumber");
}
}
Solution 4
I can't give you a complete answer...
But I think you can use the VisualTreeHelper to iterate through the children of any control http://blogs.msdn.com/b/kmahone/archive/2009/03/29/visualtreehelper.aspx
However, for the effect you are looking for, then I think using the SelectedItem Style might be a better solution - e.g. see this article - http://joshsmithonwpf.wordpress.com/2007/07/30/customizing-the-selected-item-in-a-listbox/
Solution 5
Since DataTemplate is a generic template that could be used many times in the code, there is no way to access it by name (x:Name="numberTextBox").
I solved similar problem to this by making a collection of Controls - while Listbox was populating I add Textbox control to the collection.
string text = myCollectionOfTextBoxes[listbox.SelectedIndex].Text;
Till I found a better soultion - Tag property. In your ListboxItem you bind Tag property to the name
Tag="{Binding Name}"
and the to access it
ListBoxItem listBoxItem = ContactListBox.SelectedItem as ListBoxItem;
string name = listBoxItem.Tag.ToString();
sust86
Updated on May 22, 2020Comments
-
sust86 almost 4 years
I have a ListBox including an ItemTemplate with 2 StackPanels. There is a TextBox in the second StackPanel i want to access. (Change it's visibility to true and accept user input) The trigger should be the SelectionChangedEvent. So, if a user clicks on an ListBoxItem, the TextBlock gets invisible and the TextBox gets visible.
XAML CODE:
<ListBox Grid.Row="1" Name="ContactListBox" VerticalAlignment="Stretch" HorizontalAlignment="Stretch" ItemsSource="{Binding Contacts}" Margin="0,36,0,0" SelectionChanged="ContactListBox_SelectionChanged"> <ListBox.ItemTemplate> <DataTemplate> <StackPanel Orientation="Horizontal" Margin="0,0,0,0"> <toolkit:ContextMenuService.ContextMenu> <toolkit:ContextMenu> <toolkit:MenuItem Header="Edit Contact" Click="ContactMenuItem_Click"/> <toolkit:MenuItem Header="Delete Contact" Click="ContactMenuItem_Click"/> </toolkit:ContextMenu> </toolkit:ContextMenuService.ContextMenu> <Grid> <Rectangle Fill="{StaticResource PhoneAccentBrush}" Width="72" Height="72"> <Rectangle.OpacityMask> <ImageBrush ImageSource="/Images/defaultContactImage.png" Stretch="UniformToFill"/> </Rectangle.OpacityMask> </Rectangle> </Grid> <StackPanel> <TextBox Text="{Binding Name}" TextWrapping="Wrap" Visibility="Collapsed"/> <TextBlock Text="{Binding Name}" TextWrapping="Wrap" Style="{StaticResource PhoneTextExtraLargeStyle}" /> <TextBlock Text="{Binding Number}" TextWrapping="Wrap" Margin="12,-6,12,0" Style="{StaticResource PhoneTextAccentStyle}"/> </StackPanel> </StackPanel> </DataTemplate> </ListBox.ItemTemplate> </ListBox>
I guess there are several ways to solve this, but nothing I tried worked.
My current approach looks like this
private void ContactListBox_SelectionChanged(object sender, SelectionChangedEventArgs e) { ListBoxItem listBoxItem = ContactListBox.SelectedItem as ListBoxItem; DataTemplate listBoxTemplate = listBoxItem.ContentTemplate; // How to access the DataTemplate content? StackPanel outerStackPanel = listBoxTemplate.XXX as StackPanel; StackPanel innerStackPanel = outerStackPanel.Children[1] as StackPanel; TextBox nameBox = innerStackPanel.Children[0] as TextBox; TextBlock nameBlock = innerStackPanel.Children[1] as TextBlock; nameBox.Visibility = System.Windows.Visibility.Visible; nameBlock.Visibility = System.Windows.Visibility.Collapsed; }