Wpf: Update content using scroll position - c#

You have a stackpanel with many buttons arranged vertically. The buttons contain either a date or a time. They are intermingled: "Monday", "1pm", "7pm", "Tuesday", "3pm", "11pm", "Wednesday". You can scroll down the list of buttons with a scrollviewer.
Tricky part: The top button must always show a day (i.e "Tuesday") not a time. This is to know which day the times belong to as you scroll down. For example: If you scrolled down one button the example would read: "1pm", "7pm", "Tuesday", "3pm", "11pm", "Wednesday". And you wouldn't know what day 1pm belonged to anymore without scrolling up.
Here is what I have so far:
XAML:
<DockPanel>
<Button DockPanel.Dock="Top" Content="Monday" Background="Red"/>
<Grid>
<ScrollViewer Name="sv1" CanContentScroll="True" VerticalScrollBarVisibility="Visible" HorizontalScrollBarVisibility="Visible">
<StackPanel Name="sp1">
<Button Content="1pm"/>
<Button Content="7pm"/>
<Button Content="Tuesday" Background="Red"/>
<Button Content="3pm"/>
<Button Content="11pm"/>
<Button Content="Wednesday" Background="Red"/>
</StackPanel>
</ScrollViewer>
</Grid>
</DockPanel>
C#
public partial class myWindow : Window
{
public myWindow()
{
InitializeComponent();
}
//"Logical scrolling"
private void spLineUp(object sender, RoutedEventArgs e)
{
((IScrollInfo)sp1).LineUp();
}
private void spLineDown(object sender, RoutedEventArgs e)
{
((IScrollInfo)sp1).LineDown();
}
}
How would you change the content using the scroll position?
Any help appreciated!

I found a property called "VerticalOffset" that keeps track of the row in logical scrolling. Knowing the row number then allowed updating the content.
C#
private void sChanged(object sender, ScrollChangedEventArgs e)
{
TopButton.Content = e.VerticalOffset.ToString();
}
XAML
<Button DockPanel.Dock="Top" Content="Date" Background="Red" Name="TopButton"/>
<Grid>
<ScrollViewer Name="sv1" VerticalScrollBarVisibility="Visible" CanContentScroll="True" ScrollChanged="sChanged">
<StackPanel Name="sp1">
</StackPanel>
</ScrollViewer>
</Grid>

Related

send data from one window to another c# xaml wpf

i want to send Data from one Textbox on window One to a label on window Two.
starting with window two:
<StackPanel>
<StackPanel x:Name="ButtonStackPanel" Height="Auto" Width="Auto">
<StackPanel Orientation="Horizontal">
<StackPanel Orientation="Vertical">
<Button Style="{DynamicResource ButtonStyle}" Content="To The Dark Side" Click="OnClickToDarkSide"/>
<Button Style="{DynamicResource ButtonStyle}" Content="To The Gray" Click="OnClickToGraySide"/>
<Button Style="{DynamicResource ButtonStyle}" Content="To The Light Side" Click="OnClickToLightSide"/>
</StackPanel>
<Border HorizontalAlignment="Center" VerticalAlignment="Stretch" Background="Red" Height="Auto" Width="2"/>
<Label Style="{DynamicResource LabelStyle}" x:Name="theTextBlock" Content="{Binding Source=CodeText}"/>
<Border HorizontalAlignment="Center" VerticalAlignment="Stretch" Background="Red" Height="Auto" Width="2"/>
<ToggleButton Style="{DynamicResource ToggleButtonStyle}" Content="Open Style Window" Name="StyleWindowButton" Click="OnClickOpenStyleWindow"/>
<ToggleButton Style="{DynamicResource ToggleButtonStyle}" Content="Open Text Window" Name="TextWindowButton" Click="OnClickOpenTextWindow"/>
</StackPanel>
<Border Height="2" Width="Auto" Background="Red" HorizontalAlignment="Stretch" VerticalAlignment="Center"/>
</StackPanel>
<Border Height="2" Width="Auto" Background="Red" HorizontalAlignment="Stretch" VerticalAlignment="Center"/>
</StackPanel>
Codebehind of Window Two:
public MainWindow()
{
(App.Current as App).CodeText = _jediCode;
InitializeComponent();
}
private void OnClickToDarkSide(object sender, RoutedEventArgs e)
{
(App.Current as App).ChangeSkin(Skin.Dark);
(App.Current as App).CodeText = _sithCode;
theTextBlock.Content = (App.Current as App).CodeText;
}
private void OnClickToLightSide(object sender, RoutedEventArgs e)
{
(App.Current as App).ChangeSkin(Skin.Light);
(App.Current as App).CodeText = _jediCode;
theTextBlock.Content = (App.Current as App).CodeText;
}
private void OnClickToGraySide(object sender, RoutedEventArgs e)
{
(App.Current as App).ChangeSkin(Skin.Gray);
(App.Current as App).CodeText = _grayCode;
theTextBlock.Content = (App.Current as App).CodeText;
}
private void OnClickOpenStyleWindow(object sender, RoutedEventArgs e)
{
if (StyleWindowButton.IsChecked == true)
{
styleWindow = new StyleWindow();
styleWindow.Show();
}
else
{
styleWindow.Close();
styleWindow = null;
}
}
private void OnClickOpenTextWindow(object sender, RoutedEventArgs e)
{
if (TextWindowButton.IsChecked == true)
{
textWindow = new InputWindow();
textWindow.Show();
}
else
{
textWindow.Close();
textWindow = null;
}
}
}
window one:
<Grid>
<TextBox HorizontalAlignment="Left" VerticalAlignment="Top" Height="200" Width="200" TextWrapping="Wrap"
AcceptsReturn="True" AcceptsTab="True" Text="{Binding Path=CodeText, Source={x:Static Application.Current}, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}" Margin="10,10,0,0">
<!-- TODO: trigger change from this textbox to the textblock in mainwindow -->
</TextBox>
</Grid>
code behind of one is empty.
app.xaml.cs:
public string CodeText
{
get => _codeText;
set { _codeText = value; OnPropertyChanged(nameof(CodeText)); }
}
Ok, the current behavior is clicking on one of the buttons (Dark Side, Gray, Light Side) leads to changes in the CodeText Property, which leads to a change of the content of the label of Window Two and the text of TextBox of Window One. Changing the text of the TextBox, changes also the CodeText Property, but does not lead to a change in the label and thats confusing, why does it work the one way, but not the other.
hope you have a hint for me. :) Maybe i missed a trigger or a kind of refresh for the label
bindings in window One and Two are set differently. (window Two does it wrong, Content="{Binding Source=CodeText}" is not valid binding)
in fact, window Two removes the binding by assigning CodeText directly as local value:
theTextBlock.Content = (App.Current as App).CodeText;
you should remove that line, and use the same binding as in window One:
<Label Style="{DynamicResource LabelStyle}" x:Name="theTextBlock"
Content="{Binding Path=CodeText, Source={x:Static Application.Current}}"/>

ScrollViewer ChangeView on SizeChanged

I have DataTemplate which I use in HubSection:
<DataTemplate x:Name="dataTemplate2">
<Grid x:Name="greedy">
<ScrollViewer x:Name="scroller" SizeChanged="ScrollViewer_SizeChanged" Height="{Binding Height,ElementName=greedy}" >
<ItemsControl x:Name="itemsControl"
ItemsSource="{Binding}"
ItemTemplate="{StaticResource dataTemplateDetails}">
<ItemsControl.ItemContainerTransitions>
<TransitionCollection>
<ReorderThemeTransition />
<NavigationThemeTransition />
</TransitionCollection>
</ItemsControl.ItemContainerTransitions>
</ItemsControl>
</ScrollViewer>
</Grid>
</DataTemplate>
In my ItemsControl I have items which can be expandable. What I want to achieve is that when the item will expand to see more details about that item. I want Scrollviewer to scroll down (for amount of changed size of ScrollViewer).
Code behind for SizeChanged event:
private void ScrollViewer_SizeChanged(object sender, SizeChangedEventArgs e)
{
ScrollViewer myScroll = (ScrollViewer)sender;
myScroll.ChangeView(null, myScroll.ScrollableHeight, null, false);
}
What I have done now is not working as my expectation. I scroll down to the end right now. But the thing is it scrolls only when the items extend the size of available view (ScrollBar is shown). Then if I expand another item it doesn't work. If I hide details about item (ScrollBar hides too) and expand it again it will work again.
It's like the SizeChanged event occures only when ScrollViewer is going into action but have infinite height which doesn't change.
I've tried Grid with row set to "*", it changes nothing. Now I try to set height by binding it to height of ItemsControl - still the same behaviour.
Could you help me with the solution, show the path of thinking or enlighten me with some workaround?
EDIT:
I prepared some code to work with to see what happens exactly.
1) Create New Project -> Store Apps (c#) -> Windows Phone 8.1 (Blank App) and name it "scroll"
2) Paste this code into MainPage.xaml
<Page
x:Class="scroll.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:scroll"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
Background="DarkOliveGreen">
<Page.Resources>
<DataTemplate x:Name="dataTemplateDetails">
<Grid Name="grido" Grid.Row="1" Margin="10,10,10,10">
<Grid.RowDefinitions>
<RowDefinition Height="50" />
<RowDefinition Height="Auto" />
<RowDefinition Height="50" />
<RowDefinition Height="50" />
</Grid.RowDefinitions>
<Border Grid.Row="0" Background="Black" CornerRadius="10" Opacity="0.4" />
<Border Grid.Row="1" Background="Black" CornerRadius="10" Opacity="0.3" />
<Border Grid.Row="2" Background="Black" CornerRadius="10" Opacity="0.2" />
<Border Grid.Row="3" Background="Black" CornerRadius="10" Opacity="0.1" />
<TextBlock Grid.Row="0" Text="{Binding Name}" Style="{StaticResource BaseTextBlockStyle}" HorizontalAlignment="Center"/>
<Grid Grid.Row="1" HorizontalAlignment="Center">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<TextBlock Grid.Column="0" Margin="5,0,5,0" Text="Description:" Style="{StaticResource BaseTextBlockStyle}"/>
<TextBlock Grid.Column="1" Text="{Binding Description}" Style="{StaticResource BaseTextBlockStyle}"/>
</Grid>
<TextBlock Grid.Row="2" Text="Next row" Style="{StaticResource BaseTextBlockStyle}" HorizontalAlignment="Center"/>
<TextBlock Grid.Row="3" Text="Next row" Style="{StaticResource BaseTextBlockStyle}" HorizontalAlignment="Center"/>
</Grid>
</DataTemplate>
<DataTemplate x:Name="dataTemplate2">
<Grid x:Name="greedy" >
<ScrollViewer x:Name="scroller" SizeChanged="ScrollViewer_SizeChanged" VerticalAlignment="Top">
<ItemsControl x:Name="itemsControl"
ItemsSource="{Binding}"
ItemTemplate="{StaticResource dataTemplateDetails}">
<ItemsControl.ItemContainerTransitions>
<TransitionCollection>
<ReorderThemeTransition />
<NavigationThemeTransition />
</TransitionCollection>
</ItemsControl.ItemContainerTransitions>
</ItemsControl>
</ScrollViewer>
</Grid>
</DataTemplate>
</Page.Resources>
<Page.BottomAppBar>
<CommandBar Background="Black" Opacity="0.6" x:Name="myCommandBar">
<AppBarButton Icon="Add" Label="Add" x:Name="AddItem" Click="Add_Click"/>
<AppBarButton Icon="Delete" Label="Delete" x:Name="RemoveItem" Click="Delete_Click"/>
</CommandBar>
</Page.BottomAppBar>
<Grid>
<Hub x:Name="myHub" Header="Test">
<HubSection x:Uid="myDetailsHubsection" x:Name="myDetailsHubsection" Header="Details" DataContext="{Binding Items}" ContentTemplate="{StaticResource dataTemplate2}" />
</Hub>
</Grid>
3) Paste this code into MainPage.xaml.cs
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices.WindowsRuntime;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;
namespace scroll
{
public sealed partial class MainPage : Page
{
public static Details dataContextItems;
public MainPage()
{
this.InitializeComponent();
this.NavigationCacheMode = NavigationCacheMode.Required;
dataContextItems = new Details();
}
public class TestItem
{
public string Name { get; set; }
public string Description { get; set; }
public TestItem(string n, string d)
{
Name = n;
Description = d;
}
}
public class Details : INotifyPropertyChanged
{
private ObservableCollection<TestItem> _items;
public ObservableCollection<TestItem> Items
{
set
{
_items = value;
NotifyPropertyChanged("Items");
}
get
{
return _items;
}
}
public Details()
{
_items = new ObservableCollection<TestItem>();
}
public event PropertyChangedEventHandler PropertyChanged;
private void NotifyPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}
protected override void OnNavigatedTo(NavigationEventArgs e)
{
this.DataContext = dataContextItems;
}
private void Add_Click(object sender, RoutedEventArgs e)
{
TestItem iAmAnItem = new TestItem("Name of an item", "Long and detailed description of an item");
dataContextItems.Items.Add(iAmAnItem);
}
private void Delete_Click(object sender, RoutedEventArgs e)
{
if (dataContextItems.Items.Count > 0)
dataContextItems.Items.RemoveAt(0);
}
private void ScrollViewer_SizeChanged(object sender, SizeChangedEventArgs e)
{
ScrollViewer myScroll = (ScrollViewer)sender;
myScroll.ChangeView(null, myScroll.ScrollableHeight, null, false);
}
}
}
4) Run the app
5) When you add first two items you can't scroll them but when you add more items you can see that it scrolls down as soon as items "need more space" to be shown and scrollbar occures. But with adding more items it doesn't work. If you delete items and add "third" item again it will scroll down.
I want it to scroll down everytime size of scrollviewer changes (in this case when new item occures but keep in mind it should work when item "extends" in my original solution and there can be few extended items simultaneously).
I've been tinkering with the solution and I finally found a way to do that.
I think the problem is that I didn't understand how ScrollViewer does work. I took the scrolling height as UIElement height hoping for SizeChanged to be fired what isn't truth. ScrollViewer wasn't changing its size because it just took the whole space it could and then just displayed how much content it is in it (It's like ScrollViewer has almost always infinite height unless it's less than actual available view space). With adding first two items SizeChanged event was firing with third one too and then nothing happend. It proves that.
I needed SizeChanged to be fired everytime the size of ScrollViewer (or in this case the Grid) was changing. Solution is very simple but still it needs understanding of how ScrollViewer works - and now it seems so obvious that it will never be greater than available space.
Changes made to make it work:
<DataTemplate x:Name="dataTemplate2">
<ScrollViewer x:Name="scroller" VerticalAlignment="Top" HorizontalAlignment="Stretch" IsEnabled="True" >
<Grid VerticalAlignment="Top" x:Name="greedo" SizeChanged="greedo_SizeChanged">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<ItemsControl x:Name="itemsControl"
ItemsSource="{Binding}"
ItemTemplate="{StaticResource dataTemplateDetails}">
<ItemsControl.ItemContainerTransitions>
<TransitionCollection>
<ReorderThemeTransition />
<NavigationThemeTransition />
</TransitionCollection>
</ItemsControl.ItemContainerTransitions>
</ItemsControl>
</Grid>
</ScrollViewer>
</DataTemplate>
and code behind:
private void greedo_SizeChanged(object sender, SizeChangedEventArgs e)
{
Grid takingScroll = (Grid)sender;
ScrollViewer myScroll = (ScrollViewer)takingScroll.Parent;
myScroll.ChangeView(null, myScroll.ScrollableHeight, null, false);
}

Get button content in event

I have the code in XAML:
<Button Grid.Column="0" Grid.Row="1" x:Name="btnSete" Click="btn_Click">
<ContentControl.Content>
<Viewbox Margin="3">
<TextBlock Text="7"/>
</Viewbox>
</ContentControl.Content>
</Button>
And code behind:
private void btn_Click(object sender, RoutedEventArgs e)
{
Button btn = (Button)e.Source;
txbDisplay.Text = btn.Content.ToString();
}
how do I get the value of <TextBlock Text="7"/> in btn_Click?
Based on your XAML, btn.Content should be the instance of the Viewbox. Then the Child property of the Viewbox should be your TextBlock.
So you should be able to do this (inside your button click event handler):
var viewBox = (Viewbox)btn.Content;
var textBlock = (TextBlock)viewBox.Child;
var text = textBlock.Text; // This is the value you were looking for
txbDisplay.Text = text;
Also, just as a helpful note, the <ContentControl.Content> ... </ContentControl.Content> part of your XAML is superfluous. That block could just be written as:
<Button Grid.Column="0" Grid.Row="1" x:Name="btnSete" Click="btn_Click">
<Viewbox Margin="3">
<TextBlock Text="7"/>
</Viewbox>
</Button>
See the "XAML Content Properties" section on this page for more information why that is if you're not sure.

WPF: Get the item index touched in a stack panel

I have a StackPanel. The contents of the StackPanel are defined in a Data Template and they are basically another StackPanel composed of two Buttons and two Text Blocks. Now... when I touch the StackPanel I can get the element I touched through
e.TouchDevice.DirectlyOver
Where e is a TouchEventArgs variable. But I can only get the actual UIElement... I'm intrested in getting the index of the element of the StackPanel that I touched.
Anyone knows how to do that?
Thank you.
XAML:
<DataTemplate x:Key="AddBookListTemplate">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="9.9*"/>
<ColumnDefinition Width="0.1*"/>
</Grid.ColumnDefinitions>
<StackPanel Orientation="Vertical" >
<StackPanel Orientation="Horizontal">
<Button blabla>
</Button>
<Button blabla>
</Button>
</StackPanel>
<TextBlock/>
<TextBlock/>
</StackPanel>
</Grid>
</DataTemplate>
And is reused
<ScrollViewer>
<ItemsControl ItemsSource="{Binding Books}" Margin="0 10 0 0" Background="Transparent" ItemTemplate="{StaticResource AddBookListTemplate}">
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel Orientation="Vertical" TouchEnter="StackPanel_TouchEnter"/>
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
</ItemsControl>
</ScrollViewer>
You could simply use the IndexOf method on the panel's Children collection:
private void panel_Touch(object sender, RoutedEventArgs e)
{
MessageBox.Show("You've touched n°" + panel.Children.IndexOf(sender as UIElement));
}
You could use VisualTreeHelper to walk up the visual tree, and then use IndexOf() to get the index:
private void panel_Touch(object sender, RoutedEventArgs e)
{
int index;
var button = sender as Button;
if (button != null)
{
var contentPresenter = VisualTreeHelper.GetParent(button) as ContentPresenter;
if (contentPresenter != null)
{
var stackPanel = VisualTreeHelper.GetParent(contentPresenter) as StackPanel;
if (stackPanel != null)
index = stackPanel.Children.IndexOf(contentPresenter);
}
}
}
Use a tool like Snoop to view the visual treee so you know what types to expect (I think that StackPanel puts ContentPresenters around each item, but I could be wrong).
It's a bit of a hack though. I'd recommend something more like this:
<StackPanel Orientation="Horizontal">
<Button Content="OK" Command="{Binding OKCommand}" />
<Button Content="Cancel" Command="{Binding CancelCommand}" />
</StackPanel>
Where OKCommand and CancelCommand are RelayCommands on your ViewModel.

make data grid visible on click

I have this data grid where I am placing all my buttons
<Grid x:Name="ButtonGrid" HorizontalAlignment="Left" Margin="0,90,0,4" Width="186">
<Button x:Name="B1" Content="B1" Height="18" Margin="73,0,59,16" VerticalAlignment="Bottom" Click="B1"/>
<Button x:Name="B2" Content="B2" Height="18" Margin="0,0,-2,16" VerticalAlignment="Bottom" Click="B2_Click" HorizontalAlignment="Right" Width="57"/>
</Grid>
I have the grid collapased on start. But when a button {testGrid} is clicked, I want the grid to ne visible.
Here is my code
namespace project.Test
{
public partial class MainPage : UserControl
{
public MainPage()
{
InitializeComponent();
}
EDUTED
private void testGrid_Click(object sender, System.Windows.RoutedEventArgs e)
{
FrameworkElement ButtonGrid = (sender as FrameworkElement).FindName("ButtonGrid") as FrameworkElement;
if ( ButtonGrid.Visibility == System.Windows.Visibility.Collapsed)
ButtonGrid.Visibility = System.Windows.Visibility.Visible;
else
ButtonGrid.Visibility = System.Windows.Visibility.Collapsed;
}
}
}
I think if you move your Grid outside of your DataTemplate it will work. :)
However if you really need to put it in a DataTemplate, as long as your Button is at the same level as the Grid, you should still be able to find it.
Say your xaml code looks like this,
<UserControl xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
x:Class="controlstoryboardactionrefissue.MainPage" Width="640" Height="480">
<UserControl.Resources>
<DataTemplate x:Key="DataTemplate1">
<Grid x:Name="myGrid" Height="128" Background="#FFE7C0C0" Width="333">
<Button x:Name="myButton" Content="Button" HorizontalAlignment="Left" VerticalAlignment="Top" Width="75" Margin="31,29,0,0" Click="myButton_Click" />
</Grid>
</DataTemplate>
</UserControl.Resources>
<Grid x:Name="LayoutRoot" Background="White">
<ContentControl HorizontalAlignment="Left" VerticalAlignment="Top" Margin="175,198,0,0" ContentTemplate="{StaticResource DataTemplate1}" />
</Grid>
</UserControl>
Then the code behind,
private void myButton_Click(object sender, System.Windows.RoutedEventArgs e)
{
var myButton = (Button)sender;
var grid = myButton.Parent as Grid;
if (grid != null)
{
// do stuff
}
}
Hope it helps. :)

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