I made a grid with 3 rows and 3 columns, to bind the images to it. I have a List with objects of type Post. I want to bind the images of that List to the grid. What is the proper way to do it?
Code:
<ScrollViewer Height="400" HorizontalScrollBarVisibility="Auto">
<ListBox ItemsSource="{Binding Posts}" ScrollViewer.HorizontalScrollBarVisibility="Disabled">
<ListBox.ItemsPanel >
<ItemsPanelTemplate>
<UniformGrid Rows="3" Columns="3"/>
</ItemsPanelTemplate>
</ListBox.ItemsPanel>
<Image Source="{Binding File}"></Image> <!-- Here I want to bind the image but it throws me exception: InvalidOperationException: Operation is not valid while ItemsSource is in use. Access and modify elements with ItemsControl.ItemsSource instead. -->
</ListBox>
</ScrollViewer>
Since each ListBoxItem will have a Post item as it's DataContext, You can make an DataTemplate for the ListBox.
It will be it's ItemTemplate(under a property of the same name).
In it, you can bind an Image's Source property to the image in your Post object.
The Source binding in wpf is image path, so either you make a binding path string to image source or you make it be a static resouce for accessing.
Binding Path
<Image Source="{Binding DisplayedImagePath}" />
Either in Property or ViewModel
public string DisplayedImage
{
get { return "pack://application:,,,/AssemblyName;component/Images/YourImage.png"; }
}
Static Resouce
<BitmapImage x:Key="MyImageSource"
UriSource="pack://application:,,,/AssemblyName;component/Images/YourImage.png" />
Then in your code:
<Image Source="{StaticResource MyImageSource}" />
Related
I am trying to present the usercontrol, CharacterEditorView, from within an ItemsControl. (The use of "Canvas" in the ItemsPanelTemplate can be changed, Grid?). The CharacterEditorView is to overlay on top of a character string, so position is crucial. The ItemsControl is:
<ItemsControl Grid.Row="0" Grid.RowSpan="1" ItemsSource="{Binding CharacterPads}" >
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<Canvas />
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
<ItemsControl.ItemContainerStyle>
<Style>
<Setter Property="Control.Margin" Value="{Binding Margin}"/>
</Style>
</ItemsControl.ItemContainerStyle>
</ItemsControl>
where the binding of CharacterPads is defined as:
private ObservableCollection<CharacterEditorViewModel> characterPads = new ObservableCollection<CharacterEditorViewModel>();
public ObservableCollection<CharacterEditorViewModel> CharacterPads
{
get
{
return characterPads;
}
}
I would like to present EACH CharacterEditorView within a specific rectangle known only at the time of its viewmodel creation. That is, each CharacterEditorView will have a different
rectangle to be presented in:
<UserControl x:Class="Nova5.UI.Views.CharacterEditorView"
.................................................................
<Grid Background="Red">
<TextBlock Text="TextBlock" Margin="{Binding ...?????}" />
</Grid>
</UserControl>
What binding is needed to position EACH CharacterEditorView at its own position?
Thanks for any ideas.
If you want to bind the TextBlock's Margin, you need some bindable property of type Thickness within the CharacterEditorViewModel and specify this as the binding target (or, for cleaner code, provide numeric properties in the ViewModel and implement a ValueConverter that creates a Thickness instance out of them).
Alternatively, since the ItemsPanelTemplate is already defined as Canvas, bind those numeric properties directly to Canvas.Left and Canvas.Top, as HighCore suggested.
I've created a listview. The listview's source is set to a list of "listviewitem"s. The listviewItem's content is set to the specific class that I need data from.
Somehow, the datatemplate from my xaml document is not recognised which results in a default template instead of the one I defined.
My template looks like this:
<DataTemplate x:Key="Tiled">
<StackPanel Height="100" Width="90">
<Grid Width="70" Height="70" HorizontalAlignment="Center">
<Image Source="{Binding Path=Content.Icon}" Margin="6,6,6,9"/>
</Grid>
<TextBlock Style="{Binding Path=Content.Name}" FontSize="13"
HorizontalAlignment="Center" Margin="0,0,0,1" />
</StackPanel>
</DataTemplate>
I know that I can also set the source of the list to a collection of objects instead of listviewitems, but I need the contextmenu from the listviewitems.
I know that I can also set the source of the list to a collection of objects instead of listviewitems, but I need the contextmenu from the listviewitems.
No you don't, that's what the ItemContainerStyle is for.
What you by the way should see in the output window:
System.Windows.Data Error: 26 : ItemTemplate and ItemTemplateSelector are ignored for items already of the ItemsControl's container type; Type='ListBoxItem'
I want to implement a ListBox which each item include a Image control and some other controls, then use it to binding some data. Due to this ListBox need to contains more than 2000 items, this means I have to do some optimization for it.
First, I noticed that most of the Image controls has one same picture(Default avatar), so I create a singleton ImageSource-object for the data. But although the Image control's source is the same object, you know I also need to create 2000 Image control in the ListBox with DataTemplate below:
<ListBox ItemsSource="{Binding Items}">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel>
<Image Source="{Binding Avatar}" />
<TextBlock Text="{Binding Name}" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
Is there have a way to reduce Image control object's number in my program? Thank you!
I have a collection that I wish to bind to a WPF grid.
The problem I'm facing is that the number of columns is dynamic and is dependent on a collection. Here is a simple mock up:
public interface IRows
{
string Message{get;}
IColumns[] Columns{get;}
}
public interface IColumns
{
string Header {get;}
AcknowledgementState AcknowledgementState{get;}
}
public interface IViewModel
{
ObservableCollection<IRows> Rows {get;}
}
I want my view to bind to the the Rows collection, which contains a collection of Columns.
My Columns collection contains an enum which should be represented by an image (1 of 3 possibilities). It also contains a Message property which should only be displayed in one column (static and is just some text information). It also contains a Header string which should be displayed as a header for that column.
Note that the number of columns is variable (at the moment the headers are set to Acknowledge but this will change to represent dynamic data).
Update: This is after implementing suggestions from Rachel
<ItemsControl
ItemsSource="{Binding Items, Converter={StaticResource PresentationConverter}}">
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<Grid ShowGridLines="true"
local:GridHelpers.RowCount="{Binding RowCount}"
local:GridHelpers.ColumnCount="{Binding ColumnCount}" />
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
<ItemsControl.ItemContainerStyle>
<Style>
<Setter Property="Grid.Row" Value="{Binding RowIndex}"/>
<Setter Property="Grid.Column" Value="{Binding ColumnIndex}"/>
</Style>
</ItemsControl.ItemContainerStyle>
<ItemsControl.ItemTemplate>
<DataTemplate>
<ContentControl Content="{Binding}">
<ContentControl.Resources>
<DataTemplate DataType="{x:Type UI:MessageEntity}">
<TextBox Text="{Binding Message}"></TextBox>
</DataTemplate>
<DataTemplate DataType="{x:Type UI:StateEntity}">
<TextBox Text="{Binding State}"></TextBox>
</DataTemplate>
</ContentControl.Resources>
</ContentControl>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
This almost gives me what I want now. I'm only stuck with what I should do for the headers.
Any suggestions are welcome.
You can use nested ItemsControls for this
Here's a basic example:
<!-- Bind Rows using the default StackPanel for the ItemsPanel -->
<ItemsControl ItemsSource="{Binding Rows}">
<!-- Set the Template for each row to a TextBlock and another ItemsControl -->
<ItemsControl.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<!-- Need to set Width of name TextBlock so items line up correctly -->
<TextBlock Width="200" Text="{Binding Name}" />
<ItemsControl ItemsSource="{Binding Columns}">
<!-- Use a horizontal StackPanel to display columns -->
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel Orientation="Horizontal" />
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
</ItemsControl>
</StackPanel>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
Using a grid approach might make things more complicated than they should be. Have you tried changing the template of a listview, or to use the DataGrid instead for this purpose?
For an example, take a look at this project: http://www.codeproject.com/Articles/25058/ListView-Layout-Manager
Or this one: http://www.codeproject.com/Articles/16009/A-Much-Easier-to-Use-ListView
If you go with the Grid, I believe you'll have to add a lot of code behind to manage the amount of columns and rows, their size, the cell content... Whereas a ListView/DataGrid will let you do this dynamically through Templates.
Create a Grid using code as shown at http://msdn.microsoft.com/en-us/library/system.windows.controls.grid(v=vs.90).aspx#feedback
create a property of type ColumnDefinition,( and use property changed ) to create columns.
There is also the option of using a dynamic object to create your columns. This is a bit laborious but the results are very effective and the solution in general is quite flexible.
This will show you the basics to the dynamic object
Binding DynamicObject to a DataGrid with automatic column generation?
I had some trouble using it with nested objects, columns that have objects and then trying to bind cell content to the object.
Here's a question I raised with an example of how to do this
Problems binding to a the content of a WPF DataGridCell in XAML
I am a bit baffled here. I have a List<BitmapImage> in a Viewmodel that is populating. I am trying to display the list on the view with an ItemsControl, but the Images don't show up. Oddly, I can access the same collection and get an image to display if I am using an Image tag.
<ItemsControl ItemsSource="{Binding Path=Images}" MinHeight="80">
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel Orientation="Horizontal"/>
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
<ItemsControl.ItemTemplate>
<DataTemplate>
<Image Source="{Binding}" MinWidth="80" MinHeight="80" />
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
<Image HorizontalAlignment="Left" Name="image1" Stretch="Uniform" VerticalAlignment="Top" Source="{Binding Path=Images[0]}" MinHeight="80" MaxHeight="200" />
Note that they both point to Images. The Image shows up, the ItemsControl stays empty. What is going on?
You'll solve this by using an ObservableCollection as opposed to a List. The ItemsControl isn't going to rebind on the change notification of a List. You won't have to worry about explicitly calling the change notification for the List either if you use an ObservableCollection.
I was able to replicate your scenario and simply using an ObservableCollection solves the issue. As to why: http://msdn.microsoft.com/en-us/library/system.componentmodel.inotifypropertychanged.aspx
Specifically, see this quote in the Remarks section:
For change notification to occur in a binding between a bound client and a data source, your bound type should either: Implement the INotifyPropertyChanged interface (preferred). Provide a change event for each property of the bound type. Do not do both.