Consider the following, simple code:
XAML:
<Grid Height="60" Name="grid">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="162*" />
<ColumnDefinition x:Name="coltest" Width="316*" />
<ColumnDefinition Width="239*" />
</Grid.ColumnDefinitions>
</Grid>
<Label MouseDoubleClick="TextBox_MouseDoubleClick"
Content="{Binding ElementName=coltest, Path=ActualWidth}" Grid.Row="1"/>
The MouseDoubleClick event:
private void TextBox_MouseDoubleClick(object sender, MouseButtonEventArgs e)
{
grid.RowDefinitions.Add(new RowDefinition());
for (int i = 0; i < grid.ColumnDefinitions.Count; i++)
{
Random r = new Random();
Label l = new Label { Content = r.Next(10, 1000000000).ToString() };
grid.Children.Add(l);
Grid.SetRow(l, grid.RowDefinitions.Count - 1);
Grid.SetColumn(l, i);
}
}
My label contains the ActualWidth property of the second column via a binding. In Visual Studio I see my label containing the value 316, so the binding works.
Double clicking the label triggers its event and adds an extra row to the grid, all with a random length.
I expect to see a new value at my label, but (the at runtime calculated) 0 does not change!
What am I missing here?
The main problem is that ActualWidth of a ColumnDefinition isn't a Dependency Property, nor does it implement INotifyPropertyChanged so the Binding has no way of knowing that the ActualWidth of coltest has changed.
You'll need to explicitly update the Binding
Edit2: In this case, you might be able to update the Binding in the SizeChanged event for the Grid since the Columns have * width. This won't work 100% with Auto width though since the width will change based on the elements in the ColumnDefinition
<Grid Name="grid"
SizeChanged="grid_SizeChanged">
<!--...-->
</Grid>
Event handler
void grid_SizeChanged(object sender, SizeChangedEventArgs e)
{
BindingExpression be = label.GetBindingExpression(Label.ContentProperty);
be.UpdateTarget();
}
Edit: Made some small changes to the Xaml. This will update the Binding everytime you doubleclick the first Label
<Grid Name="grid">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="162*" />
<ColumnDefinition x:Name="coltest" Width="316*" />
<ColumnDefinition Width="239*" />
<ColumnDefinition Width="239*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Label MouseDoubleClick="TextBox_MouseDoubleClick"
Name="label"
Content="{Binding ElementName=coltest, Path=ActualWidth}" Grid.Row="0"/>
</Grid>
Event handler
private void TextBox_MouseDoubleClick(object sender, MouseButtonEventArgs e)
{
grid.RowDefinitions.Add(new RowDefinition());
for (int i = 0; i < grid.ColumnDefinitions.Count; i++)
{
Random r = new Random();
Label l = new Label { Content = r.Next(10, 1000000000).ToString() };
grid.Children.Add(l);
Grid.SetRow(l, grid.RowDefinitions.Count - 1);
Grid.SetColumn(l, i);
}
BindingExpression be = label.GetBindingExpression(Label.ContentProperty);
be.UpdateTarget();
}
Related
I have a grid with some ColumnDefinitions and RowDefinitions. What I like to do is drag a control at runtime and have it snap to a given GridColumn/GridRow when the control is over that GridColumn/GridRow. I was not able to find any resources on this. Perhaps I am using the wrong key words. Thanks in advance!
You should extend Grid to handle the drop position. Let the Grid add the dropped element to the appropriate cell.
The following simple but working example shows how to enable dragging of any UIElement from a Panel such as StackPanel or Grid to the custom DrockingGrid.
The custom Grid simply overrides the relevant drag&drop overrides. It's a minimal but working example, therefore only OnDragEnter and OnDrop are overridden.
On drop, you basically have to identify the cell the element was dropped in by using the drop position from the DragEventArgs. Then remove the dropped element from its original parent container (where the drag operation has started) and then insert it into the DockingGrid. You then use Grid.Row and Grid.Column to position the element in the appropriate cell:
DockingGrid.cs
public class DockingGrid : Grid
{
private bool AcceptsDrop { get; set; }
private Brush OriginalBackgroundBrush { get; set; }
public DockingGrid()
{
this.AllowDrop = true;
}
protected override void OnDragEnter(DragEventArgs e)
{
base.OnDragEnter(e);
e.Effects = DragDropEffects.None;
this.AcceptsDrop = e.Data.GetDataPresent(typeof(UIElement));
if (this.AcceptsDrop)
{
e.Effects = DragDropEffects.Move;
ShowDropTargetEffects();
}
}
protected override void OnDragLeave(DragEventArgs e)
{
base.OnDragEnter(e);
ClearDropTargetEffects();
}
protected override void OnDrop(DragEventArgs e)
{
base.OnDrop(e);
if (!this.AcceptsDrop)
{
return;
}
ClearDropTargetEffects();
var droppedElement = e.Data.GetData(typeof(UIElement)) as UIElement;
RemoveDroppedElementFromDragSourceContainer(droppedElement);
_ = this.Children.Add(droppedElement);
Point dropPosition = e.GetPosition(this);
SetColumn(droppedElement, dropPosition.X);
SetRow(droppedElement, dropPosition.Y);
}
private void SetRow(UIElement? droppedElement, double verticalOffset)
{
double totalRowHeight = 0;
int targetRowIndex = 0;
foreach (RowDefinition? rowDefinition in this.RowDefinitions)
{
totalRowHeight += rowDefinition.ActualHeight;
if (totalRowHeight >= verticalOffset)
{
Grid.SetRow(droppedElement, targetRowIndex);
break;
}
targetRowIndex++;
}
}
private void SetColumn(UIElement? droppedElement, double horizontalOffset)
{
double totalColumnWidth = 0;
int targetColumntIndex = 0;
foreach (ColumnDefinition? columnDefinition in this.ColumnDefinitions)
{
totalColumnWidth += columnDefinition.ActualWidth;
if (totalColumnWidth >= horizontalOffset)
{
Grid.SetColumn(droppedElement, targetColumntIndex);
break;
}
targetColumntIndex++;
}
}
private void RemoveDroppedElementFromSourceContainer(UIElement droppedElement)
{
DependencyObject parent = droppedElement is FrameworkElement frameworkElement
? frameworkElement.Parent
: VisualTreeHelper.GetParent(droppedElement);
if (parent is null)
{
return;
}
switch (parent)
{
case Panel panel:
panel.Children.Remove(droppedElement);
break;
case ContentControl contentControl:
contentControl.Content = null;
break;
case ContentPresenter contentPresenter:
contentPresenter.Content = null;
droppedElement.UpdateLayout();
break;
case Decorator decorator:
decorator.Child = null;
break;
default:
throw new NotSupportedException($"Parent type {parent.GetType()} not supported");
}
}
private void ShowDropTargetEffects()
{
this.ShowGridLines = true;
this.OriginalBackgroundBrush = this.Background;
this.Background = Brushes.LightBlue;
}
private void ClearDropTargetEffects()
{
this.Background = this.OriginalBackgroundBrush;
this.ShowGridLines = false;
}
}
Usage
Use it like a normal Grid.
Now the user can drag any control into any of the predefined cells.
<local:DockingGrid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="100" />
<ColumnDefinition Width="200" />
<ColumnDefinition />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="100" />
<RowDefinition Height="300" />
<RowDefinition />
</Grid.RowDefinitions>
</local:DockingGrid>
In the parent host of the drag&drop context for example the Window, enable/start the drag behavior:
MainWindow.xaml.cs
partial class MainWindow : Window
{
protected override void OnPreviewMouseMove(MouseEventArgs e)
{
base.OnPreviewMouseMove(e);
if (e.LeftButton == MouseButtonState.Pressed
&& e.Source is UIElement uIElement)
{
_ = DragDrop.DoDragDrop(uIElement, new DataObject(typeof(UIElement), uIElement), DragDropEffects.Move);
}
}
}
See Microsoft Docs: Drag and Drop Overview to learn more about the feature.
The short answer is to put that control inside something which fills that cell. You could just put it in that grid cell by adding it to the grid children and setting grid row and column attached properties but there is a gotcha.
A grid cell is sort of conceptual.
The grid looks at it's content, looks at it's definitions for rows and columns and works out where to put it's content using measure arrange passes.
Which is a wordy way of saying there's nothing there to drag your control into.
You need a drop target to drag drop anything into. As it's name suggests, you need some sort of a receptacle for the thing you are dragging.
Wpf, however has these things called content controls.
A button actually inherits from content control to allow it to have things like a string in it.
There is also a content control itself. Which is just kind of like a receptacle for something or other.
One of these things can be used in a given cell as a sort of a place holder. And then you have something in a cell that you can drop into.
I think if you just throw a contentcontrol in a grid without anything inside it you might have problems hit testing.
Some experimentation in a scratch project is advisable.
But basically you could have something like:
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="*"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Rectangle Fill="Red"
Name="DraggAbleThing"
MouseMove="DraggAbleThing_MouseMove"
/>
<ContentControl Grid.Row="1"
Grid.Column="1"
x:Name="BottomRight"
AllowDrop="True"
>
<Rectangle Fill="Yellow"/>
</ContentControl>
</Grid>
There's a fair bit to implement in order to do drag drop but the idea here is you have something in the bottom right cell which you can drop into. You might have to set ishitestable=false on that yellow rectangle.
I'd have to implement all the drag drop methods to try it out.
If I did and drop works ok then when the contentcontrol gets draggablething dropped into it.
Set the content property of the contentcontrol to draggablething and it is now in the bottom right cell.
It will fill that cell because the grid arranges it's contents to fill whichever logical cell it decides they're "in".
I would like to present an example I wrote that is working.
In the Application I wrote I have a Grid with 4 Rows and 4 Columns.
I can place in each Cell a different UserControl that is based on a class I called
BaseDragDropUserControl:
public class BaseDragDropUserControl: UserControl
{
protected override void OnMouseMove(MouseEventArgs e)
{
base.OnMouseMove(e);
if (e.LeftButton == MouseButtonState.Pressed)
{
DataObject data = new DataObject();
data.SetData(DataFormats.StringFormat, nameof(BaseDragDropUserControl));
BaseDragDropUserControl tobemMoved = (BaseDragDropUserControl)e.Source;
int row = (int)tobemMoved.GetValue(Grid.RowProperty);
int col = (int)tobemMoved.GetValue(Grid.ColumnProperty);
data.SetData("Source", tobemMoved);
data.SetData("Row", row);
data.SetData("Col", col);
DragDrop.DoDragDrop(this, data, DragDropEffects.Move);
}
}
protected override void OnGiveFeedback(GiveFeedbackEventArgs e)
{
base.OnGiveFeedback(e);
if (e.Effects.HasFlag(DragDropEffects.Copy))
{
Mouse.SetCursor(Cursors.Cross);
}
else if (e.Effects.HasFlag(DragDropEffects.Move))
{
Mouse.SetCursor(Cursors.Pen);
}
else
{
Mouse.SetCursor(Cursors.No);
}
e.Handled = true;
}
protected override void OnDrop(DragEventArgs e)
{
base.OnDrop(e);
// If the DataObject contains string data, extract it.
if (e.Data.GetDataPresent(DataFormats.StringFormat))
{
string dataString = (string)e.Data.GetData(DataFormats.StringFormat);
if (dataString == nameof(BaseDragDropUserControl))
{
int targetRow = (int)this.GetValue(Grid.RowProperty);
int targetCol = (int)this.GetValue(Grid.ColumnProperty);
int originRow = (int)e.Data.GetData("Row");
int originCol = (int)e.Data.GetData("Col");
BaseDragDropUserControl origin = (BaseDragDropUserControl)e.Data.GetData("Source");
this.SetValue(Grid.RowProperty, originRow);
this.SetValue(Grid.ColumnProperty, originCol);
origin.SetValue(Grid.RowProperty, targetRow);
origin.SetValue(Grid.ColumnProperty, targetCol);
}
}
e.Handled = true;
}
}
The above class is the "Heavy one". It handle both the Drag and the Drop functions.
It ships data object with the origin UserControl and also intercept it when it is dropped. It switch the Grid.Row and Grid.Column values between the origin UserControl and the Target UserControl. In doing this the locations are changed.
I created 2 UsserControls.
RedUserControl and BlueUserControl:
<local:BaseDragDropUserControl x:Class="Problem10.RedUserControl"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:local="clr-namespace:Problem10"
mc:Ignorable="d"
d:DesignHeight="450" d:DesignWidth="800" AllowDrop="True">
<Grid>
<Rectangle Fill="Red"/>
</Grid>
</local:BaseDragDropUserControl>
<local:BaseDragDropUserControl x:Class="Problem10.BlueUserControl"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:local="clr-namespace:Problem10"
mc:Ignorable="d"
d:DesignHeight="450" d:DesignWidth="800" AllowDrop="True">
<Grid>
<Rectangle Fill="Blue"/>
</Grid>
</local:BaseDragDropUserControl>
The MainWindow is as following:
<Grid >
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition/>
<ColumnDefinition/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<local:RedUserControl Grid.Row="0" Grid.Column="1"/>
<local:BlueUserControl Grid.Row="0" Grid.Column="0"/>
<local:BlueUserControl Grid.Row="0" Grid.Column="2"/>
<local:BlueUserControl Grid.Row="0" Grid.Column="3"/>
<local:RedUserControl Grid.Row="1" Grid.Column="0"/>
<local:BlueUserControl Grid.Row="1" Grid.Column="1"/>
<local:BlueUserControl Grid.Row="1" Grid.Column="2"/>
<local:BlueUserControl Grid.Row="1" Grid.Column="3"/>
<local:RedUserControl Grid.Row="2" Grid.Column="0"/>
<local:BlueUserControl Grid.Row="2" Grid.Column="1"/>
<local:BlueUserControl Grid.Row="2" Grid.Column="2"/>
<local:BlueUserControl Grid.Row="2" Grid.Column="3"/>
<local:RedUserControl Grid.Row="3" Grid.Column="0"/>
<local:BlueUserControl Grid.Row="3" Grid.Column="1"/>
<local:BlueUserControl Grid.Row="3" Grid.Column="2"/>
<local:BlueUserControl Grid.Row="3" Grid.Column="3"/>
</Grid>
</Window>
The Application is ready for you ! Come and play.
private void Hangman_OnLoaded()
{
const int btnSize = 25;
for (var i = 65; i <= 90; i++)
{
var btn = new Button { Content = (char)i };
btn.Width = btn.Height = btnSize;
var margin = btn.Margin;
margin.Left += btnSize + 100;
btn.Margin = margin;
GridMain.Children.Add(btn);
}
}
So, I have this code block and i want to create alphabet with ASCII. I have a Grid named GridMain. I want to display A-Z. When I debug, I see that buttons are created in one nest. What should I use to display these letters next to each other?
Since these are buttons, that has single character ( atleast based on your question ), The size of the items will always be the same. So i would suggest you to use GridView with DataTemplate to load ASCII Characters as Buttons.
change your Hangman_OnLoaded to below.
private void Hangman_OnLoaded()
{
List<char> bindingData = new List<char>();
for (var i = 65; i <= 90; i++)
{
bindingData.Add((char)i);
}
variableGrid.DataContext = bindingData;
}
Below will be your GridView.
<GridView x:Name="variableGrid" ItemsSource="{Binding }">
<GridView.ItemTemplate>
<DataTemplate>
<Button Content="{Binding ''}" />
</DataTemplate>
</GridView.ItemTemplate>
</GridView>
If you insist on doing everything in code behind for the usual reasons, that would look more like this:
var GridMain = new System.Windows.Controls.Primitives.UniformGrid
{
Name = "GridMain",
Rows = 10,
Columns = 10
};
If for some reason you really want to use Grid, you need to define rows and columns in the Grid and set the row and column values on each Button.
XAML
<Grid x:Name="GridMain">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<!-- etc. however many rows -->
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="Auto" />
<!-- etc. however many columns -->
</Grid.ColumnDefinitions>
</Grid>
C#:
// Row zero, column zero
Grid.SetRow(btn, 0);
Grid.SetColumn(btn, 0);
Etc.
If this were WPF (it isn't, but maybe somebody doing WPF will click on this some day), your best, simplest solution is to use UniformGrid instead of regular Grid, and set the correct number of rows and columns on it:
<UniformGrid x:Name="GridMain" Rows="10" Columns="10">
</UniformGrid>
VariableSizedWrapGrid might be an acceptable UWP substitute for UniformGrid in your case, but I'm on Win7 here and can't test it.
I'm trying to build an app that displays in a Pivot informations about several products such as their pictures. Each PivotItem is concerning one product and contains (between other controls) another Pivot where I load the pictures of the product in code behind.
Here's the XAML part :
<Page
x:Class="Inventaire.Fenetres.FicheProduit"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:Inventaire"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<Page.Resources>
<ResourceDictionary>
<DataTemplate x:Key="ProductPivotItem">
<Grid x:Name="rootGrid" Loaded="rootGrid_Loaded">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<TextBlock x:Name="productName" Text="{Binding article.name}" FontSize="18"
FontWeight="Bold" HorizontalAlignment="Center" TextWrapping="Wrap"
Grid.Row="0" Grid.Column="0" Grid.ColumnSpan="2"/>
<Pivot x:Name="picturesPivot" HorizontalAlignment="Center" Margin="0,5,0,5"
VerticalContentAlignment="Top" Grid.Row="1" Grid.Column="0" Grid.ColumnSpan="2"/>
<!--
Some other controls
-->
</Grid>
</DataTemplate>
</ResourceDictionary>
</Page.Resources>
<Pivot x:Name="productPivot" ItemsSource="{Binding}"
ItemTemplate="{StaticResource ProductPivotItem}" />
</Page>
For the moment I load images in the rootGrid_Loaded event, using VisualTreeHelper to get picturesPivot with a method i found there.
Here's the C# extracts :
private void rootGrid_Loaded(object sender, RoutedEventArgs e)
{
Grid rootGrid = (Grid)sender;
// FindArticle is a method I wrote to get the product (of class Article) concerned by
// the productPivotItem, according to me irrelevant for my problem
Article art = FindArticle(rootGrid);
Pivot picturesPivot = (Pivot)FindChildControl<Pivot>(rootGrid, "picturesPivot");
loadImage(picturesPivot, art);
}
private async void loadImage(Pivot picturesPivot, Article article)
{
for (int i = 0 ; i < article.images.Count ; i++)
{
// ImageProduit is the class gathering infomations I need to build the picture url
// the images property of the Article class is the collection of ImageProduit for the product
// and I use AppelWebService (pattern singleton) to get the image from web
ImageProduit picture = article.images[i];
BitmapImage bmpImage = await AppelWebService.getInstance().loadImage(picture.ToString());
Image img = new Image();
img.Source = bmpImage;
PivotItem pi = new PivotItem();
pi.Content = img;
picturesPivot.Items.Add(pi);
}
}
private DependencyObject FindChildControl<T>(DependencyObject control, string ctrlName)
{
DependencyObject result = null;
bool done = false;
int i = 0;
int childNumber = VisualTreeHelper.GetChildrenCount(control);
while (i < childNumber && !done)
{
DependencyObject child = VisualTreeHelper.GetChild(control, i);
FrameworkElement fe = child as FrameworkElement;
if (fe == null)
{
done = true;
}
else if (child is T && fe.Name == ctrlName)
{
result = child;
done = true;
}
else
{
DependencyObject nextLevel = FindChildControl<T>(child, ctrlName);
if (nextLevel != null)
{
result = nextLevel;
done = true;
}
}
i++;
}
return result;
}
I modified a bit the FindChildControl method in order to have only one return at the end of the method.
Wrote like this I have no problems loading images.
But, sliding on many products, i discover that after around 70 productPivotItem loaded my emulator crash for OutOfMemoryException.
So I want to try to clear picturesPivot.Items when leaving the corresponding productPivotItem to see if it solve the memory problem.
For this I thought use the PivotItemLoaded and PivotItemUnloaded events on productPivot, load images on load and clear the picturesPivot items collection on unload.
Unfortunately I am not able to get back the picturesPivot in these event methods.
Here's what I tried :
private void productPivot_PivotItemLoaded(Pivot sender, PivotItemEventArgs args)
{
// Next three lines independently
args.Item.UpdateLayout();
sender.UpdateLayout();
UpdateLayout();
Pivot picturesPivot = (Pivot)FindChildControl<Pivot>(args.Item, "picturesPivot");
}
Debuging step by step I saw that args.Item has one child, a Grid without name that has himself one child, a ContentPresenter. This ContentPresenter has no child and I can't get any of my controls defined in the DataTemplate.
How could I find them ? I really need you as I had tearing out on this for too long. I hope I was clear enough, the Pivot Inside Pivot thing can be confusing.
I want to binding my itemscontrol in listbox, but it doesn't work. I want to add some FrameworkElement to Listbox with stack style.
Here is my XAML code:
<ListBox x:Name="listThemes">
<ListBox.ItemTemplate>
<DataTemplate>
<Grid Margin="5">
<Grid Grid.Column="1">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<TextBlock Text="{Binding Title}" FontWeight="Bold" />
<StackPanel Grid.Row="1" >
<ItemsControl Width="Auto"
Height="Auto"
ItemsSource="{Binding ElementName=listThemes, Path=Items}">
</ItemsControl>
</StackPanel>
</Grid>
</Grid>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
I don't know how to binding ItemsControl inside ListBox. I try put out the Binding ElementName of ItemsControl but it's always crashes. If the ElementName is page name, it not work.
Testing Class :
public class Testing
{
public string Title { get; set; }
public ObservableCollection<FrameworkElement> Items { get; set; }
}
C# Code :
observableCollection = new ObservableCollection<FrameworkElement>();
for (int i = 0; i < 3; i++)
{
observableCollection.Add(new Button { Content = i.ToString() });
observableCollection.Add(new Canvas
{
Background = new ImageBrush()
{
ImageSource = new BitmapImage(new Uri(#"Assets/ApplicationIcon.png", UriKind.Relative)),
Stretch = System.Windows.Media.Stretch.Fill
},
Height = 100,
Width = 100
});
}
List<Testing> list = new List<Testing>();
for (int i = 0; i < 3; i++)
{
Testing test = new Testing();
test.Title = "Testing";
test.Items = observableCollection;
list.Add(test);
}
listThemes.ItemsSource = list;
First, it crashes because you bind the same elements on three different item. One framework element can't be attach under two different control. So you should place your ObservableCollection in your List<Testing> creating process.
Second, you should set a DataContext to your listThemes control, so its items can find the right data path to bind and then you could remove the ElementName.
Try these code.
List<Testing> list = new List<Testing>();
for (int i = 0; i < 3; i++)
{
Testing test = new Testing();
test.Title = "Testing";
var observableCollection = new ObservableCollection<FrameworkElement>();
for (int j = 0; i < 3; i++)
{
observableCollection.Add(new Button { Content = j.ToString() });
observableCollection.Add(new Canvas
{
Background = new ImageBrush()
{
ImageSource = new BitmapImage(new Uri(#"Assets/ApplicationIcon.png", UriKind.Relative)),
Stretch = System.Windows.Media.Stretch.Fill
},
Height = 100,
Width = 100
});
}
test.Items = observableCollection;
list.Add(test);
}
listThemes.DataContext = list;
listThemes.ItemsSource = list;
Third, I don't think it is a good way to bind your FrameworkElement directly to an ItemsControl. It just look weird.
Update:
If you want to generate different types of items, you can use DataTemplateSelector. Because you already parse the forum data into different type, so please check this post:
How to Control the DataTemplateSelector in Windows Store Apps
It explains how to use DataTemplateSelector to display different type of data.
Why is your inner collection of type FrameworkElement?
Create a custom type for it and set an ItemTemplate for your inner ItemsControl.
<DataTemplate x:Key=NestedItemsTemplate>
....
</DataTemplate>
<ListBox x:Name="listThemes"
ItemsSource="{Binding TestItems}">
<ListBox.ItemTemplate>
<DataTemplate>
<Grid Margin="5">
<Grid Grid.Column="1">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<TextBlock Text="{Binding Title}" FontWeight="Bold" />
<StackPanel Grid.Row="1" >
<ItemsControl
Width="Auto" Height="Auto"
ItemsSource="{Binding ElementName=listThemes, Path=Items}"
ItemTemplate="{StaticResource NestedItemsTemplate}">
</ItemsControl>
</StackPanel>
</Grid>
</Grid>
</DataTemplate>
</ListBox.ItemTemplate>
I am trying to figure out how to use a WPF list box in conjunction with a window that has its SizeToContent property set to WidthAndHeight. The MainWindow has a grid with two rows and two columns. In the bottom right quadrant, I have a list box. I want the rest of the controls in the window to control the size of the window, and the list box to simply fill the available space. Currently, the list box is expanding to fit its contents, which causes the entire MainWindow to expand.
Note: I attempted to create a simple example, but want to point out that in my real scenario I'm using MVVM, and the controls that I want to determine the window width/height are bound to properties in a viewmodel that have their values set after the window is loaded.
Edit to add: The list box is bound to its content before the controls that I want to determine size are, and I don't have control over that.
Here is what the MainWindow currently looks like at startup:
Notice the red and blue bars which indicate what I'm not wanting to happen. Content in that area should only be visible by scroll bars.
Here is what I want the MainWindow to look like at startup:
Notice the size of the MainWindow is determined by the text blocks along the top and left sides, and the list box fills the available space and uses scrollbars if necessary.
Here is some sample code...
MainWindow.xaml:
<Window x:Class="WpfApplication1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" SizeToContent="WidthAndHeight">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="auto"/>
<RowDefinition Height="auto"/>
<RowDefinition />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="auto"/>
<ColumnDefinition />
</Grid.ColumnDefinitions>
<Grid Grid.Column="1">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="auto"/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<TextBlock Text="The window should fit to the width of this" FontSize="15"/>
<Canvas Background="Red" Grid.Column="1"/>
</Grid>
<Grid Grid.Row="1" Grid.RowSpan="2">
<Grid.RowDefinitions>
<RowDefinition Height="auto"/>
<RowDefinition/>
</Grid.RowDefinitions>
<TextBlock Text="The window should fit to the height of this" FontSize="15">
<TextBlock.LayoutTransform>
<RotateTransform Angle="-90"/>
</TextBlock.LayoutTransform>
</TextBlock>
<Canvas Background="Blue" Grid.Row="1"/>
</Grid>
<Grid Grid.Row="2" Grid.Column="1">
<ListBox Name="ListBox1">
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding}" />
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
</Grid>
MainWindow.xaml.cs:
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
var Messages = new ObservableCollection<string>() { "This is a long string to demonstrate that the list box content is determining window width" };
for (int i = 0; i < 16; i++)
Messages.Add("Test" + i);
for (int i = 0; i < 4; i++)
Messages.Add("this text should be visible by vertical scrollbars only");
ListBox1.ItemsSource = Messages;
}
}
Set the list box ItemsSource, and set SizeToContent=Manual after the Window has loaded.
public MainWindow()
{
InitializeComponent();
Loaded += OnLoaded;
}
private void OnLoaded(object sender, RoutedEventArgs routedEventArgs)
{
SizeToContent = SizeToContent.Manual;
var messages = new ObservableCollection<string>
{
"This is a long string to demonstrate that the list" +
" box content is determining window width"
};
for (int i = 0; i < 16; i++)
{
messages.Add("Test" + i);
}
for (int i = 0; i < 4; i++)
{
messages.Add("this text should be visible by vertical scrollbars only");
}
ListBox1.ItemsSource = messages;
}
In this way the main window is initially sized to fit the content (with no data in the listbox), and then the listbox displays its items with scrollbars.