Xamarin Forms ListView Data Binding - xaml

ObservableCollection<string> CompanyList in the xaml.cs code behind is tied to <ListView> element in the xaml. Left alone, it displays a list of the strings in CompanyList as expected.
However, I want to customize (purely for style purposes) the ViewCell in the ListView while leaving CompanyList as a collection of strings. I am unsure how to bind the string company list value.
<ListView x:Name="CompanyList" ItemTapped="OnAddCompanyFilterTapped" >
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<StackLayout Padding="0" Spacing="0">
<StackLayout Padding="10">
<Label Text="{Binding ??????????}" HorizontalOptions="Fill"/>
</StackLayout>
<BoxView Style="{StaticResource divider}"/>
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
What do I put in the ??????? to get the string in CompanyList to show?
Any help/suggestions/ideas is greatly appreciated!

Binding Path=. should do it, which can be shortened:
<Label Text="{Binding}" HorizontalOptions="Fill"/>
Assumes the ListView.ItemsSource remains CompanyList.

Related

I am not able to access x:Name of lable controls in ListView in XAML and Code behind

I have a ListView in Xamarin forms which has a Viewcell in it. The Viewcell contains an lable control with a x:Name attribute. Now I tried to x:name in code behind but it is showing compile time error(The x:name does not exists in current context).
The below code im using.
<ListView x:Name="UnPaidInvoicesList"
SeparatorVisibility="None" IsPullToRefreshEnabled="True"
HasUnevenRows="True"
ItemSelected="UnPaidInvoicesList_ItemSelected"
VerticalOptions="FillAndExpand">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell >
<StackLayout x:Name="stkDuedate" Orientation="Horizontal">
<Label x:Name="lblDueDate1" Text="Due Date:" TextColor="Gray" />
<Label x:Name="lblDueDate" TextColor="{StaticResource Pink}" />
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>```
Im new to this xamarin forms. Please help on this.
What features do you want to implement?
Just as Jason said,elements inside a template cannot be referenced by name.
If you want to disply a data list , you can bind the data to a ListView.
For this, you can refer to the following code:
<ListView x:Name="lstView" RowHeight="60" ItemsSource="{Binding veggies}" HasUnevenRows="True" IsPullToRefreshEnabled="False" SelectionMode="None">
<ListView.ItemTemplate >
<DataTemplate>
<ViewCell>
<StackLayout Orientation="Horizontal" HorizontalOptions="Fill" BackgroundColor="Olive">
<StackLayout Orientation="Vertical">
<Label Text = "{Binding Name}" FontSize="24" AbsoluteLayout.LayoutBounds="0.25, 0.25, 400, 40"/>
<Label Text = "{Binding Type}" AbsoluteLayout.LayoutBounds="50, 35, 200, 25"/>
</StackLayout>
<Image Source="{Binding Image}" HorizontalOptions="End" AbsoluteLayout.LayoutBounds="250.25, 0.25, 50, 50 "/>
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
For more,you can check document Xamarin.Forms ListView and
Customizing ListView Cell Appearance.
You can also check the sample Xamarin.Forms - ListView Sample: Custom Cells.

<Button Text="{Binding .}"/> doesn't work as intended

I have a CollectionView where the ItemsSource is bound with a List. The contents of this list should be displayed in the Text of the Button. To do this I use Text={Binding .}.
When the page loads, I get empty buttons with no text. If I then remove the . and retype it in the {Binding .}, the text will appear in my buttons.
Can someone explain this to me or explain what I'm doing wrong?
.xaml
<StackLayout>
<CollectionView x:Name="ItemsListView" ItemsSource="{Binding CurrentQuizItem.Answers}" SelectionMode="None">
<CollectionView.ItemTemplate>
<DataTemplate>
<StackLayout >
<Button Text="{Binding .}" Command="{Binding Source={RelativeSource AncestorType={x:Type viewmodel:TakeQuizPageViewModel}}, Path=AnswerClickedCommand}" Style="{StaticResource AnswerButton}"/>
</StackLayout>
</DataTemplate>
</CollectionView.ItemTemplate>
</CollectionView>
</StackLayout>

Why is the Image.Margin in a CollectionView template not creating visual space?

We have a ListView bound to a List of objects of a type called Trial. Each Trial has a property, called Pictures, that is a List of objects of a type, Picture, that represents an image and some metadata. We are using a horizontal CollectionView within the ListView item template to display thumbnails of the images, if any. The problem is in getting a little space between the images. We've tried setting a Margin property value on the Image in the CollectionView item template, but the images are still appearing right next to each other as seen in the illustration.
This is the XAML describing the ListView:
<ListView x:Name="trialsListView"
ItemsSource="{Binding .}"
ItemTapped="Handle_ItemTapped"
CachingStrategy="RecycleElement"
HasUnevenRows="True">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<StackLayout Padding="20">
<Label
Text="{Binding Prompt}"
BackgroundColor="{Binding TrialType, Converter={StaticResource TrialTypeToColorConverter}}"
Padding="5" />
<Label Text="{Binding Response}" />
<CollectionView
BindingContext="{Binding Pictures}"
ItemsSource="{Binding .}"
ItemsLayout="HorizontalList"
HeightRequest="{Binding Count, Converter={StaticResource PicturesCountToHeightConverter}}">
<CollectionView.ItemTemplate>
<DataTemplate>
<Image
HeightRequest="80"
Source="{Binding PictureName, Converter={StaticResource PictureNameToImageSourceConverter}}"
Margin="10" />
</DataTemplate>
</CollectionView.ItemTemplate>
</CollectionView>
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
And this is an example of output (from an iOS device):
I suppose we can enclose the Image in a Frame or some layout, but that feels like a 90s web hack. Surely there is a right way to get some spacing without resorting to adding screen elements? What do I not yet understand here?

Using TextCell in a StackLayout in a ListView

Why can I not use a TextCell like this in a ListView item template? When I use it the rows render but they are empty.
<ListView ItemsSource="{Binding Courses}">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<StackLayout Orientation="Vertical">
<TextCell Text="{Binding Title}" Detail="{Binding SubTitle}"></TextCell>
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
When using a Label I can see the text contents in each row:
<ListView ItemsSource="{Binding Courses}">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<StackLayout Orientation="Vertical">
<Label Text="{Binding Title}"></Label>
<Label Text="{Binding SubTitle}"></Label>
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
Is there anyway I can use the TextCell inside the list item template? I am trying to build a more complext layout inside the StackLayout and it would be greatly simplified if I could re-use the Title/Detail structure of the TextCell.
According to the Xamarin.Forms Cell Reference, cells are only designed to be added to ListViews or TableViews. In particular, it says:
However Cell is not a visual element, it just describes a template for
creating a visual element.
So it cannot be added directly to the children of a StackLayout. You will have to create a ViewCell with a custom template for that.. You can probably look at the source code on Github to find out the proper spacing that a TextCell uses between it's Text and TextDetail labels, to keep it consistent.
You Can Use Stack Layout in a text cell!
Here is the way for using it.
<TextCell>
<TextCell.BindingContext>
<StackLayout Orientation="Horizontal" >
<Label Text="{Binding Name}"
HorizontalOptions="CenterAndExpand" TextColor="Black"/>
<Label Text="{Binding Description}"
HorizontalOptions="CenterAndExpand" TextColor="Black"/>
<Label Text="{Binding Price}"
HorizontalOptions="CenterAndExpand" TextColor="Black"/>
</StackLayout>
</TextCell.BindingContext>
</TextCell>

Xamarin.Forms Vertical StackLayout in ListView displays only one (first) Child

<ListView
ItemsSource="{Binding Messages}"
Grid.ColumnSpan="2"
HeightRequest="100">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<ViewCell.View>
<StackLayout>
<Label
Text="{Binding When}"
XAlign="Center"/>
<StackLayout
BackgroundColor="Gray"
Orientation="Vertical"
VerticalOptions="Center">
<Label
Text="{Binding Message}"
XAlign="Start"/>
<Label
Text="{Binding Sender}"
XAlign="Start"
TextColor="Red"/>
</StackLayout>
</StackLayout>
</ViewCell.View>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
I am rendering a custom ListView in Xamarin.Forms application. The StackLayout which contains two Labels (to which "Message" and "Sender" has been bound), currently displays only one child. With the code above, it displays only "Message". If I change code to be
<StackLayout
BackgroundColor="Gray"
Orientation="Vertical"
VerticalOptions="Center">
<Label
Text="{Binding Sender}"
XAlign="Start"
TextColor="Red"/>
<Label
Text="{Binding Message}"
XAlign="Start"/>
</StackLayout>
it displays only sender. In short it is displaying only first child. What have I done wrong here ?
Issue was similar to what #Grisha had pointed out. RowHeight was proving to be lesser, and the second StackLayout was getting clipped.
The solution was to set HasUnevenRows property of the ListView to be TRUE. Thus, RowHeight was calculated automatically.