How to change listview datatemplate in c# dynamically - c#

I have a custom made item template for my listview with which values getting bound in .xaml itself.
I want to change one of the image dynamically in c# side.
I know in c# I can change in ContainerContentChanging but I am not able to access the custom templates image in c# please guide me out of this problem.
Here is my listview
<ListView ItemsSource="{Binding testList}" IsItemClickEnabled="True" ContainerContentChanging="ListView_ContainerContentChanging">
<ListView.ItemTemplate>
<DataTemplate>
<Grid HorizontalAlignment="Stretch">
<Grid.RowDefinitions>
<RowDefinition Height="1*" />
<RowDefinition Height="2" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="0.80*"></ColumnDefinition>
<ColumnDefinition Width="0.20*"></ColumnDefinition>
</Grid.ColumnDefinitions>
<StackPanel Margin="0,8,0,8" Grid.Row="0" Grid.Column="0" VerticalAlignment="Center">
<StackPanel Orientation="Horizontal">
<TextBlock FontSize="20" Margin="0,8,0,4" Text="{Binding textVal1}" />
<Image Name="imgStatus" Source="ms-appx:///Assets/Icons/ic_test.png" Height="36" />
</StackPanel>
<TextBlock FontSize="18" Margin="0,0,0,4" Text="{Binding textVal2}" />
<TextBlock FontSize="21" Margin="0,0,0,0" Text="{Binding textVal3}" TextWrapping="WrapWholeWords" MaxLines="2" />
</StackPanel>
</Grid>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
I thought lets have the data template in a separate c# file ... but I am not able to link up the c# file inside the grid.
Any help to access the image from the data template is appreciated.

If you define the templates as a static resource, or elsewhere where they can be referenced in XAML, you can use a custom converter with appropriate bindings to handle the change in template.
However, I believe changing the ListView.ItemTemplate will affect all items in the collection. In order to change the template of individual items, you will have to add a wrapper object and modify that object's content (which you can do in a similar manner).
I understand you wished to change the template in C#, but I believe XAML's declarative style should be sufficient.

Related

How to change telerik WPF RadGridView column filtering view template

We are using telerik controls in our project. I want to change telerik Radgrid view's (For WPF) filtering view.
As of now it looks like this as shown below:
And I want to change the text being show to actual color, so that it looks more realistic for the user to filter. Something like this:
How to get hold of the template of filtering view and inject the color rectangle there.
How to get hold of the template of filtering view and inject the color rectangle there.
The ControlTemplate can be found in Telerik.Windows.Controls.GridView.xaml:
<ControlTemplate x:Key="FilteringControlTemplate" TargetType="grid:FilteringControl">
...
I customized the ItemTemplate (for the Office2013 theme) to achieve the following, which should give you an indication of what needs to be done. You could also have a look at the CustomFilterControl example.
<ListBox.ItemTemplate>
<DataTemplate>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="20" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<CheckBox
Content=""
FontSize="13"
Grid.Column="0"
IsChecked="{Binding IsActive, Mode=TwoWay}"
VerticalAlignment="Center"/>
<Rectangle
Fill="{Binding ConvertedValue, Converter={StaticResource DistinctValueConverter}}"
Grid.Column="1"
Height="16"
Width="30" />
</Grid>
</DataTemplate>

UserControl in DataTemplate does not bind correctly

I've been trying to create a custom menu. For this reason I wanted to use an ItemsControl in order to make it flexible. After hours of headache I figured out how to make it - kinda.
I have my custom ItemsControl "LiftMenu" (which is not yet much custom but standard) and an UserControl called "LiftItem". Last but not least I got the Model-class "LiftMenuItem".
By adding a new LiftMenuItem to the LiftMenu, it should display a new LiftItem-control as corresponding item. So far so good, I managed to get this working.
In that LiftItem-control I bind like I would in a normal DataTemplate: plain bindings with a path, nothing more. Normally this would work just fine because the DataTemplate already has it's context set to the model-type.
But now I just get an empty control that does nothing and shows nothing, because the bindings don't work.
I implemented it this way:
<menu:LiftMenu HorizontalAlignment="Stretch" VerticalAlignment="Stretch" MinHeight="200" Background="#80A8A8A8" Margin="5,0,0,0">
<menu:LiftMenu.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel Orientation="Vertical" />
</ItemsPanelTemplate>
</menu:LiftMenu.ItemsPanel>
<menu:LiftMenu.ItemTemplate>
<DataTemplate DataType="{x:Type menu:LiftMenuItem}">
<menu:LiftItem />
</DataTemplate>
</menu:LiftMenu.ItemTemplate>
<menu:LiftMenuItem Header="Test1"/>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="4"/>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<Border x:Name="border" BorderBrush="{Binding LabelColor}" BorderThickness="1" HorizontalAlignment="Left" Height="Auto" Margin="0"
VerticalAlignment="Stretch" Width="4" Background="{Binding BorderBrush, ElementName=border}"/>
<TextBlock Text="{Binding Header}" TextTrimming="CharacterEllipsis" Margin="5,0,5,0" HorizontalAlignment="Left" VerticalAlignment="Center"
Foreground="White" />
<controls:ProgressRing x:Name="ring" Grid.Column="2" HorizontalAlignment="Right" Stroke="#ffff8000" VerticalAlignment="Center"
Minimum="0" Maximum="100" Value="{Binding ProcessValue}" IsIndeterminate="{Binding ProcessIndeterminate}" Visibility="{Binding ProcessVisibility}"
Width="20" Height="20" Radius="10" Margin="2,0,2,0" />
</Grid>
In the end there is no text, no border. Just the ProgressRing is visible.
How can I fix this? This ListItem-control should become similiar to a button, thus I need to do some styling (animation, ...). I can't do this within a normal DataTemplate, but I don't want to miss the binding features of WPF on that. This would make it relatively unflexible.
What's the problem? I probably just miss some DataContext or so, but I don't know what it would be.

Set textBlock text that is inside a datatemplate from C# (XAML)

I'm starting to try to create a modern app with C# and XAML. I've already worked with C# but I never touched in a XAML or WPF piece of code, so I've a beginner question..
I'm using a MSFT template Hub App (XAML) but I don't know how can I set the text value on a TextBlock through the C# code if that textblock is inside the datatemplate.
Is there somebody who can help me with this one?
I already googled for it but I can't get any site with that answer/explanation.
This is an example about what I'm trying to do:
XAML:
<DataTemplate >
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Image Source="Assets/MediumGray.png" Stretch="Fill" Width="420" Height="280"/>
<TextBlock Style="{StaticResource SubheaderTextBlockStyle}" Grid.Row="1" Margin="0,10,0,0" TextWrapping="Wrap"
x:Uid="Section1Subtitle" Text="{Binding Score}"/>
<TextBlock x:Name="desc" Grid.Row="2" Margin="0,10,0,0"
x:Uid="DescriptionHeader" Text="{Binding Test}"/>
<TextBlock x:Name="texttest" Grid.Row="3"
Text="{Binding Name}"/>
</Grid>
</DataTemplate>
C# code:
public class Class1
{
string name = "This is a test";
public string Name
{
get { return name; }
set { name = value; }
}
}
What am I doing wrong here?
Thanks in advance,
Problem solved.
Thanks a lot for you help.
Here is the code with the changed which allow me to get the variable from C#:
<DataTemplate>
<Grid>
<Grid.DataContext>
<local:Class1/>
</Grid.DataContext>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Image Source="Assets/MediumGray.png" Stretch="Fill" Width="420" Height="280"/>
<TextBlock Style="{StaticResource SubheaderTextBlockStyle}" Grid.Row="1" Margin="0,10,0,0" TextWrapping="Wrap"
x:Uid="Section1Subtitle" Text="{Binding Score}"/>
<TextBlock x:Name="desc" Grid.Row="2" Margin="0,10,0,0"
x:Uid="DescriptionHeader" Text="{Binding Test}"/>
<TextBlock x:Name="texttest" Grid.Row="3"
Text="{Binding Name}"/>
</Grid>
</DataTemplate>
This one will also walks you through many aspects of the WP development, including using devices, live tiles, etc:
http://www.jeffblankenburg.com/2011/10/31/31-days-of-mango/
It's a bit old though.
Usually there is no way to set something inside of a DataTemplate easily in c# code. However, there are some messy ways to do it through binding, converters, and selectors.
XAML provides a simple and powerful way to auto-update data between the
business model and the user interface. This mechanism is called
DataBinding. Everytime when the data of your business model changes,
it automatically reflects the updates to the user interface and vice
versa. This is the preferred method in WPF to bring data to the user
interface.
Databinding can be unidirectional (source -> target or target <-
source), or bidirectional (source <-> target).
try out the link Learn XAML.
In abstraction, a DataTemplate is a Visual representation of a certain piece of Data.
UI elements inside a DataTemplate should reflect the state of such piece of data.
In XAML-based technologies, DataBinding helps in keeping the UI in sync with the data, using really clean and beautiful declarative means, as opposed to traditional procedural programming.
So, say you have a certain piece of data, like:
public class Person
{
public string FirstName {get;set;}
public string LastName {get;set;}
}
Then you may have a DataTemplate which represents that data, like:
<DataTemplate DataType="local:Person">
<StackPanel>
<TextBlock Text="{Binding LastName}"/>
<TextBlock Text="{Binding FirstName}"/>
</StackPanel>
</DataTemplate>
The key is in the {Binding} declarations.
See the above linked MSDN article for more information.

How to group controls inside Grid for reuse in XAML?

In my application I have some controls that logically belongs together and is reused many places in different windows. The controls are always placed inside a grid.
Instead of copying the controls (and the code behind) each time I want to use them, I would like to define and maintain them in a single xaml file as a single UserControl.
I have this now:
<Grid>
<Grid.ColumnDefinitions>
[ColumnDefinitions...]
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
[RowDefinitions...]
</Grid.RowDefinitions>
<StackPanel Grid.Column="0" Grid.Row="0">
<TextBlock Text="Caption" />
<Border Padding="2" x:Name="myBorder">
<TextBox TabIndex="1" x:Name="myTxt"/>
</Border>
</StackPanel>
<ListBox x:Name="myList" Grid.Column="0" Grid.Row="0" Grid.RowSpan="2" Margin="5,50,5,0" Height="100" VerticalAlignment="Top" Visibility="Collapsed" />
[More controls..]
</Grid>
But I want to reuse this part:
<StackPanel Grid.Column="0" Grid.Row="0">
<TextBlock Text="Caption" />
<Border Padding="2" x:Name="myBorder">
<TextBox TabIndex="1" x:Name="myTxt"/>
</Border>
</StackPanel>
<ListBox x:Name="myList" Grid.Column="0" Grid.Row="0" Grid.RowSpan="2" Margin="5,50,5,0" Height="100" VerticalAlignment="Top" Visibility="Collapsed" />
as a single control - but how do I define the Grid.Column when using the control (somehow supplying it as a parameter)? - and how do I set the Grid.RowSpan value (eventhough the code is moved to a new xaml file, and not defined inside a grid)?
Any comments?
Make them into a separate usercontrol, then include that in your project.
If you're using Blend, it's really easy, just select all the controls, right click and Make into Usercontrol.
You could also make it into a resource.
Define it in a ResourceDictionary and include the dictionary the places you want to use it.
There is one catch - the resource dictionary returns the same instance everytime - so you have to add the attribute x:Shared="false".
But the wpf way is to figure out how you can do it with a DataTemplate :)

Using TextWraping within a TextBox, inside a Grid for use within a ListBox in WP7

I am trying to get my data to display properly within a GridLayout, which is to be used as a DataTemplate for an Item within ListBox. Here is the code associated with what I am doing:
<Grid Name="FeedItemTemplate">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="*" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<Image Source="{Binding ProfileImage}" Grid.RowSpan="2" Height="75" Width="75" VerticalAlignment="Center" Margin="1" />
<TextBlock Text="{Binding UserName}" Grid.Column="1" Foreground="#FFC8AB14" FontSize="28" HorizontalAlignment="Left"/>
<TextBlock Text="{Binding TimeStamp}" Grid.Column="2" TextWrapping="Wrap" FontSize="18" HorizontalAlignment="Center"/>
<TextBlock Text="{Binding Message}" Grid.Column="1" Grid.Row="1" Grid.ColumnSpan="2" TextWrapping="Wrap" FontSize="24" />
</Grid>
The issue is that using this layout, when TextWrapping is set to Wrap, the Item is displayed correctly, but when scrolling through the ListBox everything is really jittery, you cannot scroll in small increments, and it just jumps all over the place.
Any reason why it does this? As I said, only when TextWrapping is set to Wrap it does this. When its not used, it scrolls fine, but the text is all along one line and off the screen.
Does it keep jumping if you explicitly set the top-level Grid element's width to a fixed size?
For some reason that I do not fully understand, settings the ListBox's ItemsPanel property to a StackPanel might solve your problem:
<UserControl.Resources>
<ItemsPanelTemplate x:Key="MyItemsPanelTemplate">
<StackPanel/>
</ItemsPanelTemplate>
</UserControl.Resources>
...
<ListBox ... ItemsPanel="{StaticResource MyItemsPanelTemplate}"/>
This is a known issue with listbox scrolling in the current ctp when you have variable height items. The workaround for now is to set a fixed height on your listbox item content. You'll probably also notice the scroll bar doesnt properly go to the bottom all the time. The workaround fixes that too.
Reference.

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