I am upgrading a Xamarin forms app to Dotnet MAUI. I have a control that allows the user to pick one or more files from the device, saves the details in an IEnumerable<FileResult> and displays the list in a view. In the Xamarin version, the relevant XAML looks like this:
<CollectionView x:Name="AttachmentList" ItemsSource="{Binding Attachments}" SelectedItem="{Binding SelectedAttachment}" SelectionMode="Single">
<CollectionView.ItemTemplate>
<DataTemplate x:DataType="essentials:FileResult" >
<StackLayout Spacing="0">
<Frame Style="{StaticResource AttachmentBubble}">
<StackLayout Orientation="Horizontal">
<Image Source="{Binding FullPath}" HeightRequest="80" />
<Label Text="{Binding FileName}" HorizontalOptions="StartAndExpand"/>
</StackLayout>
</Frame>
</StackLayout>
</DataTemplate>
</CollectionView.ItemTemplate>
</CollectionView>
MAUI doesn't recognise the datatype "essentials:FileResult" (fair enough as there is no longer an Essentials namespace in MAUI). FileResult is in the Microsoft.Maui.Storage namespace.
I've tried replacing the DataTemplate entry with:
<DataTemplate x:DataType="FileResult" >
and
<DataTemplate x:DataType="storage:FileResult" >
but neither work, giving me an error that the type FileResult (or storage:FileResult) does not exist.
What is the MAUI equivalent that I need to make this work?
because FileResult is in a different assembly than your page, you have to specify the namespace and the assembly
xmlns:storage="clr-namespace:Microsoft.Maui.Storage;assembly=Microsoft.Maui.Essentials"
Related
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.
I am currently working with a Xamarin app for reading RFID temperature tags and updating their values in real time. The current setup uses two Horizontal StackLayouts, one with a ListView showing a list of tags and their values, and the other with a Grid of Images of the human body that I wish to display the values on as well (in specific places).
In the ListView side, I can successfully call an object called TagInfoList, which is an ObservableCollection in the Class I call from the BasePage initialization. However, on the Grid side, I've tried multiple methods of using the TagInfoList, but it does not work. I've tried BindableLayouts, DataTemplates + ViewCells, and none allow me to get TagInfoList usable within my second StackLayout.
Here is the XAML code for the two horizontal StackLayouts:
<StackLayout Orientation="Horizontal" HorizontalOptions="StartAndExpand">
<ListView x:Name="liewViewTagData" ItemsSource="{Binding TagInfoList}" SelectedItem="{Binding objItemSelected, Mode=TwoWay}">
<ListView.Header>
<StackLayout BackgroundColor="#cccccc">
<Grid>
<!-- Grid + Label code irrelevant to my issue-->
</Grid>
</StackLayout>
</ListView.Header>
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<StackLayout Orientation="Vertical">
<Grid>
<!-- Grid + Label code irrelevant to my issue-->
</Grid>
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</StackLayout> <!-- RFID Tag Section -->
<StackLayout Orientation="Horizontal" HorizontalOptions="EndAndExpand"> <!-- Body Model Section -->
<!-- HERE: WHAT TO PUT FOR TagInfoList TO BE USABLE? -->
<Grid VerticalOptions="FillAndExpand" HorizontalOptions="FillAndExpand" WidthRequest="400" ColumnSpacing="0">
<!-- Grid + Label + Images I want to use TagInfoList information in -->
</Grid>
<!-- HERE: WHAT TO PUT FOR TagInfoList TO BE USABLE? -->
</StackLayout> <!-- Body Model Section -->
</StackLayout>```
I've deleted the bulk of inside Grids since it's not relevant. TagInfoList is an ObservableCollection of a class which contains all the data I need (strings and ints). How do I utilize TagInfoList within the second StackLayout? If I do it the same method as the first StackLayout, I get an error that I've called TagInfoList twice (through the 'liewViewTagData' item). Here is that code in the .xaml.cs file:
liewViewTagData.ItemSelected += (sender, e) => {
if (e.SelectedItem == null) return; // Don't do anything if we just de-selected the row
((ListView)sender).SelectedItem = null; // De-select the row
};
My sole goal is to use the TagInfoList ObservableCollection within both StackLayouts, but I'm not sure how to do that.
Thanks!
If I do it the same method as the first StackLayout, I get an error
that I've called TagInfoList twice (through the 'liewViewTagData'
item).
You can do it in the same way as the first StackLayout.And you can change property x:Name of the two listviews to different Name.
You can refer to the following code:
<ScrollView Orientation="Horizontal">
<StackLayout Orientation="Horizontal" HorizontalOptions="StartAndExpand">
<StackLayout Orientation="Horizontal" HorizontalOptions="EndAndExpand">
<ListView x:Name="liewViewTagData" RowHeight="60" ItemsSource="{ Binding TagInfoList}">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<!--other code-->
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</StackLayout>
<StackLayout Orientation="Horizontal" HorizontalOptions="EndAndExpand">
<ListView x:Name="liewView2" RowHeight="60" ItemsSource="{ Binding TagInfoList}">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<!--other code-->
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</StackLayout>
</StackLayout>
</ScrollView>
Note:
If you run out of horizontal space, I suggest you add a ScrollView to the outer layer.
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?
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>
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.