Selected items of listview checkbox in MVVM WPF - wpf

Question

I want to pass selected items of listview checkbox in view model, later I will use further process to store in database.
Code in the FormWeek.xaml as
<Window.DataContext>
<Binding Source="{StaticResource Locator}" Path="TaskExecDefModel"></Binding>
</Window.DataContext>
<Window.Resources>
<ResourceDictionary>
<DataTemplate x:Key="ItemDataTemplate">
<CheckBox
x:Name="checkbox"
Content="{Binding}" Command="{Binding CheckBoxCommand}" CommandParameter="{Binding ElementName=checkedListView, Path=SelectedItems}"
IsChecked="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ListViewItem}}, Path=IsSelected}" />
</DataTemplate>
</ResourceDictionary>
<StackPanel Grid.Column="1" Grid.Row="3" Margin="5">
<CheckBox x:Name="selectAll" Content="Select all" Click="OnSelectAllChanged"/>
<ListView x:Name="checkedListView" SelectionMode="Multiple" ItemsSource="{Binding CollectionOfDays}" DataContext="{Binding}"
ItemTemplate="{StaticResource ItemDataTemplate}" SelectedValue="WorkingDay"
CheckBox.Unchecked="OnUncheckItem" SelectionChanged="SelectDays" SelectedItem="{Binding SelectedItems}">
</ListView>
</StackPanel>
Code in FormWeek.xaml.cs
private void SelectDays(object sender, SelectionChangedEventArgs e)
{
(this.DataContext as TaskExecDefinitionViewModel).OnCheckBoxCommand(checkedListView.SelectedItems,true);
}
My View Model TaskWeek.cs as follows
//Declaration
private RelayCommand<object> _checkBoxCommand;
public ObservableCollection<string> CollectionOfDays { get; set; }
public ObservableCollection<string> SelectedItems { get; set; }
public RelayCommand<object> CheckBoxCommand
{
get
{
if (_checkBoxCommand == null)
{
_checkBoxCommand = new RelayCommand<object>((args) => OnCheckBoxCommand(args,true));
// _checkBoxCommand = new RelayCommand(() => OnCheckBoxCommand(object args));
}
return _checkBoxCommand;
}
}
//Constructor
CollectionOfDays = new ObservableCollection<string>();
//Method
private void GetWeekDays()
{
try
{
Application.Current.Dispatcher.BeginInvoke(DispatcherPriority.Background, new Action(() =>
{
CollectionOfDays.Add("Saturday");
CollectionOfDays.Add("Sunday");
CollectionOfDays.Add("Monday");
CollectionOfDays.Add("Tuesday");
CollectionOfDays.Add("Wednesday");
CollectionOfDays.Add("Thursday");
CollectionOfDays.Add("Friday");
}));
}
catch(Exception Ex)
{
MessageBox.Show(Ex.Message, "TaskWeek:GetWeekDays");
}
}
public void OnCheckBoxCommand(object obj, bool _direction)
{
try
{
if (SelectedItems == null)
SelectedItems = new ObservableCollection<string>();
if (obj != null)
{
SelectedItems.Clear();
StringBuilder items = new StringBuilder();
if (_direction)
{
foreach (string item in CollectionOfDays)
{
items.AppendFormat(item + ",");
}
}
MessageBox.Show(items.ToString());
}
else
SelectedItems.Clear();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message, "TaskDefinition:OnCheckBoxCommand");
}
}
And below is button click commond to save the data.
<Button Grid.Column="2" Grid.Row="2" Content="Save" HorizontalAlignment="Center" VerticalAlignment="Bottom"
Command="{Binding InsertExecDefCommand}" Margin="5" >
Now my requirement is to pass selected listview items to view model through command object. I had done this using following code in FormWeek.xam.cs through SelectionChanged event as
private void OnSelectedItems(object sender, RoutedEventArgs e)
{
StringBuilder items = new StringBuilder();
foreach (string item in checkedListView.SelectedItems)
{
items.AppendFormat(item + ",");
}
string AllDays= items.ToString();
}
But please let me know how to achieve this logic through MVVM. How to get selecteditems in my view model TaskWeek.cs
After R&D and google i had done chages through RelayCommand. In OnCheckBoxCommand method foreach statement is wrong it is passing all days. I want to pass only selected listview item. Please suggest me what is wrong in OnCheckBoxCommand method.

Answer 1

Here are my findings;
use this code in code behind of FormWeek.xaml:
private void SelectDays(object sender, SelectionChangedEventArgs e)
{
(this.DataContext as TaskExecDefinitionViewModel).OnCheckBoxCommand(checkedListView.SelectedItems,true);
}
And in 'OnCheckBoxCommand': -
public void OnCheckBoxCommand(object obj, bool _direction)
{
try
{
if (SelectedItems == null) SelectedItems = new ObservableCollection<string>();
if (obj != null)
{
SelectedItems.Clear();
var _list = ((IList)obj).Cast<string>().ToList();
if (_direction)
{
_list.ForEach(item => SelectedItems.Add(item));
}
}
else
SelectedItems.Clear();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message, "TaskDefinition:OnCheckBoxCommand");
}
}
Have a nice day man.....keep going.

Answer 2

Hi try something like this
<StackPanel Grid.Column="1" Grid.Row="3" Margin="5">
<CheckBox x:Name="selectAll" Content="Select all" Command="{Binding CheckBoxCommand}" CommandParameter="{Binding IsChecked, RelativeSource={RelativeSource Mode=Self}}"/>
<ListView x:Name="checkedListView" SelectionMode="Extended" ItemsSource="{Binding CollectionOfDays}" SelectedItem="{Binding SelectedItems}"/>
</StackPanel>
public class MainViewModel
{
public MainViewModel()
{
CollectionOfDays = new ObservableCollection<string>();
SelectedItems = new ObservableCollection<string>();
CollectionOfDays.Add("Saturday");
CollectionOfDays.Add("Sunday");
CollectionOfDays.Add("Monday");
CollectionOfDays.Add("Tuesday");
CollectionOfDays.Add("Wednesday");
CollectionOfDays.Add("Thursday");
CollectionOfDays.Add("Friday");
}
private CommandHandler _checkBoxCommand;
public CommandHandler CheckBoxCommand
{
get
{
return _checkBoxCommand ?? (_checkBoxCommand=new CommandHandler((param)=>OnCheckBoxCommand(param)));
}
}
public ObservableCollection<string> CollectionOfDays { get; set; }
public ObservableCollection<string> SelectedItems {get;set;}
private void OnCheckBoxCommand(object obj)
{
if (obj is bool)
{
if (SelectedItems == null)
SelectedItems = new ObservableCollection<string>();
if ((bool)obj)
{
SelectedItems.Clear();
foreach (var item in CollectionOfDays)
{
SelectedItems.Add(item);
}
}
else
SelectedItems.Clear();
}
}
}
public MainWindow()
{
InitializeComponent();
DataContext = new MainViewModel();
}
I hope this will give you an idea.