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How do I get selecteditem from ListView in XAML?

This may be a duplicate. But I have tried everything I could find, and I cannot make it work.
Why does this not work? SelectedCourse is allways null. I have tested everything else, and it works fine. It is just getting the selected Item who is the problem.
This is my ViewModel:
public Course SelectedCourse { get; set; }
public async Task CoursesListViewClick(object sender, ItemClickEventArgs e)
{
var students = await coursesDataAccess.GetCourseStudentsAsync(SelectedCourse.CourseID); //THIS IS NULL
foreach (Student s in students)
CourseStudents.Add(s);
}
This is my XAML code:
<ListView Grid.Column="0"
x:Name="lvCourses"
IsItemClickEnabled="True"
DataContext="{x:Bind ViewModel}"
ItemsSource="{Binding Courses, Mode=OneWay}"
SelectedItem="{Binding SelectedCourse, Mode=TwoWay}"
ItemClick="{x:Bind ViewModel.CoursesListViewClick}"
Margin="10">
<ListView.ItemTemplate>
<DataTemplate x:DataType="model:Course">
<StackPanel Height="250">
<TextBlock
FontSize="50"
HorizontalAlignment="Center"
VerticalAlignment="Center"
Text="{x:Bind Name}"
Style="{StaticResource TitleTextBlockStyle}"/>
</StackPanel>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>

Why does this not work? SelectedCourse is allways null.
Since you have bound the SelectedItem property and ItemClick event, when you click the listViewItem, it will first trigger the CoursesListViewClick method which bound with the ItemClick event and then trigger the setter method of SelectedCourse to set the value. So in the CoursesListViewClick method, the SelectedCourse hasn't been assigned a value, it is always null.
The e.ClickedItem from CoursesListViewClick method represents the current item you clicked, you can directly use it to operate.
public async Task CoursesListViewClick(object sender, ItemClickEventArgs e)
{
Course selectedCourse = e.ClickedItem as Course;
var students = await coursesDataAccess.GetCourseStudentsAsync(selectedCourse.CourseID); //THIS IS NULL
foreach (Student s in students)
CourseStudents.Add(s);
}

if you use:
listView.ItemTapped += async (sender, e) =>
{
e.Item;
}
you can then manipulate what you want to do depending on the item id
Hope this helps!

Stop Checkbox event from firing multiple times

So I am having an issue where I have a GridView's ItemsSource bound to a collection of object. I also have a column of Check boxes that can be used to select object the user wishes to remove and all related items. The problem I am having is that when the user selects one item, I get stuck in a loop of the items being continually selected. Does anyone have an idea on how I can stop the programmatic selection of these check boxes from firing the Checked event.
Property in use:
List<MyObject> _localCollection = new List<MyObject>();
List<MyObject> LocalCollection
{
get { return _localCollection; }
set
{
_localCollection = value;
OnPropertyChanged("LocalCollection");
}
}
Loose example of XML code:
<GridView Name="grdItems">
<GridViewColumn>
<GridViewColumn.Header>
<CheckBox/>
</GridViewColumn.Header>
<!--Column Template-->
<GridViewColumn.CellTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<CheckBox Tag="{Binding ObjID}"
IsChecked="{Binding ToRemove, Mode=OneWay}"
Checked="SelectRelative" />
</StackPanel>
</DataTemplate>
</GridViewColumn.CellTemplate>
</GridViewColumn>
The "SelectRelative" method looks as follows:
private void SelectRelative(object sender, RoutedEventArgs e)
{
Dispatcher.BeginInvoke((Action)(() =>
{
//Get the Object Id we need
int selectedId = Convert.ToInt32(((CheckBox)sender).Tag);
//Get all objects that share this ID
List<MyObjects> objLst = new List<MyObjects>(((IEnumerable<MyObjects>)grdItems.ItemsSource));
//Clear the local collection property of our items used in the items source
LocalCollection.Clear();
//Remove the items source since we are updating it
grdItems.ItemsSource = null;
//Go through each item in the list and if the object id's match select them to remove
foreach(var item in objLst)
{
if(item.ObjId == selectedId)
item.ToRemove = true;
//Add the object to our property
LocalCollection.Add(item);
}
//Re-establish the item source with our new collection
grdItems.ItemsSource = LocalCollection;
}));
}

try this:
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<CheckBox x:Name="chkboxPaid" Checked="chkboxPaid_Checked" Content="check" Style="{StaticResource MaterialDesignCheckBox}" IsChecked="{Binding Path=IsSelected, Mode=TwoWay,
RelativeSource={RelativeSource FindAncestor,
AncestorType={x:Type DataGridRow}}}"/>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>

Iterate through ComboBox items when using CheckBox as ItemTemplate

I using a ComboBox with CheckBox as ItemTemplate and I want to iterate through all items, get their checked status and write their content to a string if checked is true. The problem is that I am using a SqlDataReader to fill and bind the ComboBox from database and I can't find a way to access the items IsChecked property.
<ComboBox>
<ComboBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<CheckBox Click="CheckBox_Click" Content="{Binding}" IsChecked="{Binding Path=IsSelected, Mode=TwoWay}" Tag="{RelativeSource FindAncestor, AncestorType={x:Type ComboBox}}"/>
</StackPanel>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
I have tried casting the ComboBox items as CheckBoxes on the click event of them this way:
private void CheckBox_Click(object sender, RoutedEventArgs e)
{
for (int i = 0; i < myComboBox.Items.Count; i++)
{
CheckBox cb = (myComboBox.Items[i] as CheckBox);
if (cb.IsChecked == true)
{
myString += "," + myComboBox.SelectedItem.ToString() + "";
}
}
}
but cb always returns NULL. I am guessing it is something with the IsChecked property binding.
I'd like to get this working but I don't want to create an object/class to fill the combobox because I need it to be filled with database. I'd really appreciate any help.

You could do something like this (I'm not stick to MVVM pattern) and this is written on the fly :
public ArrayList List { get; set; }
public MainWindow()
{
InitializeComponent();
SqlDataReader rdr = cmd.ExecuteReader();
List = new ArrayList();
while (rdr.Read()){
List.Add(new Class{ Id = rdr.GetString(0), Value = rdr.GetString(1), IsChecked= rdr.GetString(1) as bool}); //this class will contain the same data schema in your datareader but using properties
}
rdr.Close();
DataContext = List;
}
<ComboBox Name="ComboBox" ItemsSource="{Binding}" >
<ComboBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<CheckBox Tag="{Binding Id}" Content="{Binding Name}" IsChecked="{Binding IsChecked}"/>
</StackPanel>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>

WPF: ListView SelectedItem binding works for a split second, then changes back

let me start by introducing my current setup:
I have a ListView that binds its SelectedItem property to the ViewModel, like this:
<ListView Name="FileListView" ItemsSource="{Binding ImageList}"
SelectionChanged="ImageSelectionChanged"
SelectedItem="{Binding SelectedItem, Mode=TwoWay}"
SelectionMode="Single">
<ListView.ItemTemplate>
<DataTemplate>
<view:FileListItem />
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
It's item template (view:FileListItem) is the following:
<Grid MouseDown="FileListItemMouseDown" KeyDown="FileListItemKeyDown">
....
<TextBlock Name="NewNameTextBlock"
Text="{Binding NewName}"
Grid.Column="2"
Visibility="{Binding TextBlockVisibility}" />
<TextBox Name="NewNameTextBox"
Text="{Binding NewName, UpdateSourceTrigger=PropertyChanged}"
Grid.Column="2"
Visibility="{Binding TextBoxVisibility}" />
</Grid>
The idea here is to switch on the TextBox and switch off the TextBlock when the corresponding ListView item is being edited. This works ok, but when I hit a particular key, I want the ListView to select the next item and put that item into editing mode. I catch the KeyDown event as seen above in the ItemTemplate and broadcast a message, which is caught in the DataContext of my ListView like this:
public ImageFile SelectedItem {
get { return _selectedItem; }
set { _selectedItem = value; NotifyPropertyChanged("SelectedItem"); }
}
public void SelectAndEditThisHandler (object x)
{
ImageFile file = x as ImageFile;
SelectedItem = file;
}
The result is that the selection actually changes for a split second, but then it changes back to the previous selection. I suspect some other UI elements might be handling my key-presses and doing something to change the selection back, but I can't figure out which elements and how to pinpoint them.
Any help would be greatly appreciated! Thanks!
EDIT:
As requested, the SelectionChanged handler:
private void ImageSelectionChanged(object sender, SelectionChangedEventArgs e)
{
System.Collections.IList filelist = FileListView.SelectedItems;
if (filelist.Count == 1)
{
ImageFile selectedFile = FileListView.SelectedItem as ImageFile;
Mediator.Instance.NotifyColleagues(Mediator.Operations.ImagePathSelected, selectedFile.OriginalPath);
}
}
The mediator message broadcast doesn't do anything related to these controls/this problem at all.

Get selected item from a ListBox at hold

I've got a ListBox in a WP7 App where I want to do something with an item when the user hold it. The event work's great. My hold method gets called, but I can't detect which element in the list was hold.
ListBox.SelectedItem is always -1 and a code from another post on stackoverflow doens't work:
FrameWorkelement element = (FrameworkElement) e.OriginalSource;
ItemViewModel item = (ItemViewModel) element.DataContext;
I get an InvalidCastException when running it in the second line.

The following code should work.
private void StackPanel_Hold(object sender, GestureEventArgs e)
{
ItemViewModel itemViewModel = (sender as StackPanel).DataContext as ItemViewModel;
string t = itemViewModel.LineOne;
}
Note: before using the DataContext of the sender object, make sure you cast the sender object to the correct class. In this example I use a StackPanel in my DataTemplate:
<ListBox x:Name="MainListBox" Margin="0,0,-12,0" ItemsSource="{Binding Items}" >
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Margin="0,0,0,17" Height="78" Hold="StackPanel_Hold">
<TextBlock Text="{Binding LineOne}" />
<TextBlock Text="{Binding LineTwo}" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>