Hello
I am creating a windows app with a listbox. i have placed a textbox and a check box inside Listview that are being generated dynamically using C#. I want to Un check all check boxes on button click event. My XAML code is .
<ListBox Name="lstcontacts" ItemsSource="{Binding}" Margin="10,52,10,113" SelectionMode="Multiple" Foreground="#FF333333" >
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<CheckBox x:Name="contactChk" Tag="{Binding}" IsChecked="true" IsEnabled="True" Foreground="Black" Background="Black" BorderBrush="Black" Checked="chbox_checked" />
<TextBlock Name="txtResults" Text="{Binding Path=DisplayName, Mode=OneWay}" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
and my C# code is as follows.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Navigation;
using Microsoft.Phone.Controls;
using Microsoft.Phone.Shell;
using Microsoft.Phone.Data;
using Microsoft.Phone.UserData;
using Microsoft.Phone.Tasks;
using System.Data;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using Microsoft.Phone.Controls;
namespace MyPhoneBackup
{
public partial class CreateContactBackups : PhoneApplicationPage
{
//AddressChooserTask addressChooserTask;
//PhoneNumberChooserTask addressChooserTask;
public CreateContactBackups()
{
InitializeComponent();
Contacts cContacts = new Contacts();
cContacts.SearchCompleted += new EventHandler<ContactsSearchEventArgs>(ContactsSearch);
cContacts.SearchAsync(String.Empty, FilterKind.DisplayName, null);
/* addressChooserTask = new PhoneNumberChooserTask();
addressChooserTask.Completed += new EventHandler<PhoneNumberResult>(addressChooserTask_Completed);
//addressChooserTask.Completed += new EventHandler<AddressResult>(addressChooserTask_Completed); */
}
/*
void addressChooserTask_Completed(object sender, PhoneNumberResult e)
{
if (e.TaskResult == TaskResult.OK)
{
txtDisplay.Text = "The address for " + e.DisplayName + " is " + e.PhoneNumber;
}
}*/
private void Button_Click_2(object sender, RoutedEventArgs e)
{
/*try
{
addressChooserTask.Show();
}
catch (System.InvalidOperationException ex)
{
}*/
}
void ContactsSearch(object sender, ContactsSearchEventArgs e)
{
try
{
lstcontacts.DataContext = e.Results;
}
catch (System.Exception)
{
txtResults.Text = "No Results Available";
}
if (lstcontacts.Items.Any())
{
txtResults.Text = "Below is the List of Contacts";
}
else
{
txtResults.Text = "No Results Available";
}
}
private void Button_Click_1(object sender, RoutedEventArgs e)
{
//CheckBox contactChk = lstcontacts.SelectedItem as CheckBox;
SearchVisualTree(this.lstcontacts);
int count22 = lstcontacts.Items.Count;
for (int i = 0; i <= count22; i++ )
{
ListBoxItem item = this.lstcontacts.ItemContainerGenerator.ContainerFromIndex(i) as ListBoxItem;
CheckBox contactChk = FindFirstElementInVisualTree<CheckBox>(item);
contactChk.IsChecked = false;
}
}
private void SearchVisualTree(DependencyObject targetElement)
{
var count = VisualTreeHelper.GetChildrenCount(targetElement);
if (count == 0)
return;
for (int i = 0; i < count; i++)
{
var child = VisualTreeHelper.GetChild(targetElement, i);
if (child is TextBlock)
{
TextBlock myItems = (TextBlock)child;
if (myItems.Text == "Item2") {
myItems.Foreground = new SolidColorBrush(Colors.Green);
return;
}
}
else
{
SearchVisualTree(child);
}
}
}
private T FindFirstElementInVisualTree<T>(DependencyObject parentElement) where T : DependencyObject
{
var count = VisualTreeHelper.GetChildrenCount(parentElement);
if (count == 0)
return null;
for (int i = 0; i <= count; i++)
{
var child = VisualTreeHelper.GetChild(parentElement, i);
if (child != null && child is T)
{
return (T)child;
}
else
{
var result = FindFirstElementInVisualTree<T>(child);
if (result != null)
return result;
}
}
return null;
}
public void chbox_checked(object sender, RoutedEventArgs e) {
}
}
}
If i remove variable int count22 and loop below this and replace index i in ContainerFromIndex(i) with a digit then this program works fine other wise it shown following exception "An exception of type 'System.InvalidOperationException' occurred in System.Windows.ni.dll but was not handled in user code" at
var count = VisualTreeHelper.GetChildrenCount(parentElement);
in FindFirstElementInVisualTree method. If any one can help me . Please help.