Develop Reference

How to prevent uncheck (unselect) gridview item in windows Universal app

In Windows Universal app, I have a pivot table which every tab content have gridview, gridview items are multi select mode,
What I want that if any one item once checked (selected), then it unable to unselect(uncheck)
<Grid DataContext="{Binding Path=Value}">
<GridView x:Name="categoryItemsGV"
Margin="5,5,0,0"
SizeChanged="categoryItemsGV_SizeChanged"
IsItemClickEnabled="True"
ItemClick="categoryItemsGV_ItemClick"
SelectionMode="Single"
ItemsSource="{Binding}">
<GridView.ItemContainerStyle>
<Style TargetType="GridViewItem">
<Setter Property="HorizontalContentAlignment" Value="Stretch"/>
<!--<Setter Property="VerticalContentAlignment" Value="Center"/>-->
</Style>
</GridView.ItemContainerStyle>
<GridView.ItemTemplate>
<DataTemplate>
<Grid Width="195" Height="43" Margin="3">
<StackPanel Width="193" Height="40" Background="Gray" Opacity="0.5" HorizontalAlignment="Right" VerticalAlignment="Bottom" />
<StackPanel Orientation="Horizontal" Width="193" Height="40" Padding="7,7,0,0" Background="#FDFCC2" HorizontalAlignment="Left" VerticalAlignment="Top">
<TextBlock Text="{Binding ProductOptionLineName}" FontSize="18" MaxLines="1" TextTrimming="CharacterEllipsis" Visibility="{Binding Converter={StaticResource langToVisibilityConverter}, ConverterParameter='CH', Mode=OneWay}">
</TextBlock>
<TextBlock Text="{Binding ProductOptionLineNameEn}" FontSize="18" MaxLines="1" TextTrimming="CharacterEllipsis" Visibility="{Binding Converter={StaticResource langToVisibilityConverter}, ConverterParameter='EN', Mode=OneWay}"/>
<TextBlock Text="{Binding ExtraPriceString}" FontSize="18" Margin="2,0,0,0"></TextBlock>
</StackPanel>
</Grid>
</DataTemplate>
</GridView.ItemTemplate>
</GridView>
</Grid>
private async void categoryItemsGV_ItemClick(object sender, ItemClickEventArgs e)
{
var item = e.ClickedItem as ProductOptionLineModel;
}

We can use the SelectRange(ItemIndexRange) method to selects a block of items described by the ItemIndexRange.
When you call SelectRange(ItemIndexRange), all items in the specified range are selected, regardless of their original selection state. You can select all items in a collection by using an ItemIndexRange with a FirstIndex value of 0 and a Length value equal to the number of items in the collection.
For more info, see Remarks of the SelectRange(ItemIndexRange).
We can use the ItemClick to get which item is be clicked. Then we can add the SelectionChanged event and set the number of the clicked item to the SelectRange method.
For example:
private int number;
private void categoryItemsGV_ItemClick(object sender, ItemClickEventArgs e)
{
var item = e.ClickedItem as ProductOptionLineModel;
number = ProductOptionLineModels.IndexOf(item);
}
private void categoryItemsGV_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
categoryItemsGV.SelectRange(new ItemIndexRange(number, 1));
}

If we want to keep item selected as it was already selected, use below approach.
private async void categoryItemsGV_ItemClick(object sender, ItemClickEventArgs e)
{
var item = e.ClickedItem as ProductOptionLineModel;
GridView gv = sender as GridView;
gv.SelectedItems.Remove(item);
}
and if we want to keep item deselect on click (prevent deselected) for validation purpose. used below approach.
private async void categoryItemsGV_ItemClick(object sender, ItemClickEventArgs e)
{
var item = e.ClickedItem as ProductOptionLineModel;
await _viewModel.DialogService("FirstRequireMinOption", "", true);
GridView gv = sender as GridView;
gv.SelectedItems.Add(item);
}

XAML detect if listview item is focused or not

I am trying to detect which item in a listview is focused, but I am not getting the events detected. I am developing for Xbox One UWP, so I cannot use mouse or keyboard events, only focus can be used.
<ListView.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Vertical" GotFocus="StackPanel_GotFocus" >
<StackPanel Name="Imagestack" Orientation="Horizontal">
<Image Source="{Binding Image}" Height="144" Width="256" HorizontalAlignment="Center" VerticalAlignment="Center"/>
</StackPanel>
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding Title}" HorizontalAlignment="Center" VerticalAlignment="Center"/>
</StackPanel>
</StackPanel>
</DataTemplate>
</ListView.ItemTemplate>
private void StackPanel_GotFocus(object sender, RoutedEventArgs e)
{
Debug.WriteLine("Image focus");
Image img = sender as Image;
Bgimage.Source = img.Source;
}

You should register to the ListView.GotFocus event.
The OriginalSource from the event parameter will be the ListViewItem which has received the focus. You can then retrieve the item content using ListViewItem.Content.
XAML:
<ListView x:Name="list" GotFocus="list_GotFocus">
<ListView.ItemTemplate>...</ListView.ItemTemplate>
</ListView>
Code behind:
private void list_GotFocus(object sender, RoutedEventArgs e)
{
var focusedItem = (e.OriginalSource as ListViewItem)?.Content;
}

You don't need to get focus state to get data from the clicked ListViewItem, the ItemClick event of the ListView may be what you're looking for:
<ListView x:Name="LV_Items"
IsItemClickEnabled="True"
ItemClick="LV_Items_ItemClick"
>
</ListView>
private void LV_Items_ItemClick(object sender, ItemClickEventArgs e)
{
// Get instance of the model in the clicked ListViewItem
MyModel myModel = (MyModel)e.ClickedItem;
Image img = myModel.Image;
}

MVVM WPF listbox mouse leftclick event firing

I am building a WPF application with MVVM architecture. In one form I have 2 listboxes and I want to perform filter based search. I am using a common search textbox, so I have to differentiate the search based on which listbox is selected. Please find my sample listbox below:
<HeaderedContentControl Header="Visible Objects:" Height="120" Width="250" Margin="20,20,20,0">
<ListBox Name="lstObjects" Height="100" Margin="5" ItemsSource="{Binding ProfileObjTypeToBind, Mode=OneWay}">
<ListBox.ItemTemplate>
<DataTemplate>
<CheckBox Name="chkbxVisibleObjects" Grid.Column="1"
Content="{Binding Path=Value}" IsChecked="{Binding Path=flag,Mode=TwoWay}">
</CheckBox>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</HeaderedContentControl>
<HeaderedContentControl Header="User Groups to View:" Height="120" Width="250" Margin="20,10,20,10">
<ListBox Name="lstGroups" Height="100" Margin="5" ItemsSource="{Binding ProfileUserGrpToBind, Mode=OneWay}">
<ListBox.ItemTemplate>
<DataTemplate>
<CheckBox Name="chkAllowedGroups" Content="{Binding Path=GroupName}"
IsChecked="{Binding Path=flag,Mode=TwoWay}">
</CheckBox>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</HeaderedContentControl>
All I want to do is identify the listbox selected and perform the filtering based on text entered in textbox. Please help me
Thanks a lot in advance.

You can't have a selected ListBox AND be able to write stuff to a TextBox. You can save the reference to your last ListBox though using SelectionChanged or some other method
private ListBox SelectedListBox = null;
private void ListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
SelectedListBox = (sender as ListBox);
}
once you have a reference to your last selected ListBox you can add TextChanged event to your TextBox:
private void TextBox_TextChanged(object sender, TextChangedEventArgs e)
{
if (SelectedListBox == null)
return;
string searchText = (sender as TextBox).Text;
SelectedListBox.Items.Filter = (i) => { return ((string)i).Contains(searchText); }; // Or any other condition required
}

ComboBox ItemSource ObservationCollection

I have a combo box that have item source that bind to observation collection and with Data-template as the item-template. I have a problem when i click at the combo box .value and it doesn't show the value of the selected value in the combo box
Below is my Data Template:
<DataTemplate x:Key="ComboBoxTemplate">
<StackPanel Orientation="Horizontal">
<Rectangle Fill="{Binding ColorCode}" Width="30" Height="15"/>
<TextBlock Text="{Binding ColorName}" Margin="5,0,0,0"/>
</StackPanel>
</DataTemplate>
Below is my combo box:
<ComboBox Name="cmbAccentColors" Grid.Column="1" Width="130" Height="20"
ItemsSource="{Binding Source={StaticResource ComboColorData}}"
ItemTemplate="{StaticResource ComboBoxTemplate}"
IsSynchronizedWithCurrentItem="True" MaxDropDownHeight="120"
SelectionChanged="cmbColors_SelectionChanged"
>
Private void cmbColors_SelectionChanged(object sender, System.Windows.Controls.SelectionChangedEventArgs e)
{
if (!IsLoaded)
{
return;
}
MessageBox.Show(cmbAccentColors.SelectedItem.ToString());
}

Add DisplayMemberPath to your combobox. DisplayMemberPath specifies the path.
DisplayMemberPath = "YourProperty";
Also this how you access the selected Item,
Private void cmbColors_SelectionChanged(object sender, System.Windows.Controls.SelectionChangedEventArgs e)
{
string text = (sender as ComboBox).SelectedItem.Text;
}

How to get selected list view item for context menu click event

I need help to get Selected list view item details, when context menu assigned to list view items is clicked.
<ListView.Resources>
<ContextMenu x:Key="GvRowMenu" ItemsSource="{Binding ContextMenuItems}">
<ContextMenu.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<Image Source="{Binding IconPath}"></Image>
<TextBlock Text="{Binding Name}"></TextBlock>
<MenuItem
Click="MenuItem_Click"
CommandParameter="{Binding RelativeSource={RelativeSource Self}, Path=DataContext.RunCommand}" />
This is a click event code
private void MenuItem_Click(object sender, RoutedEventArgs e)
{
//what needs to de here?
}
I wrote this piece of code in my view model, but it doesnt trigger on execute method
RunCommand = new DelegateCommand<object>(OnRunCommand, CanRunCommand);
private void OnRunCommand(object obj)
{
// use the object here...
}
private bool CanRunCommand(object obj)
{
return true;
}
Let me know, how can I handle this situation. Any examples related to same will be appreciated.
Thanks

you are mixing you methods... you can run an event or you can use a command, but not so much both together.
what you want is to bind the command:
<MenuItem Command="{Binding DataContext.RunCommand}" />
there are many wonderfull sources of info out there... here is one.

Thanks..!
Well, below piece of code worked for me.
private void MenuItem_Click(object sender, RoutedEventArgs e)
{
MenuItem menuItem = (MenuItem)e.Source;
ContextMenu contextMenu = menuItem.CommandParameter as ContextMenu;
ListViewItem item = (ListViewItem)contextMenu.PlacementTarget;
var x = ((myViewModel)(item.Content)).myModel;
//'x' gives all required data of list view item
}
This is my XAML
<ListView.Resources>
<ContextMenu x:Key="GvRowMenu" ItemsSource="{Binding ContextMenuItems}">
<ContextMenu.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<Image Source="{Binding ImagePath}"/>
<TextBlock Text="{Binding Name}"/>
<MenuItem Click="MenuItem_Click"
CommandParameter="{Binding
RelativeSource={RelativeSource
AncestorType={x:Type ContextMenu}}}"/>
</StackPanel>
</DataTemplate>
</ContextMenu.ItemTemplate>
</ContextMenu>
</ListView.Resources>