Xamarin how to load image contorol if Url is an image and if video load video control-CodePudding

I am developing Facebook like feeds page where i have a list of Urls ( videos and images ). How can i load in xaml the Ui control specific to the Url type ( image or video ).

Example :

   ```<CollectionView ItemsSource="{Binding UrlList}">
            <Grid>
                If ( url is image)


                <Image Source="{Binding Url}"/>

                If ( url is video )

                <MediaElement Source="{Binding Url}" />
            </Grid>
     </CollectionView>```

CodePudding user response：

Yes, you can use DataTemplateSelector to achieve this.

A DataTemplateSelector can be used to choose a DataTemplate at runtime based on the value of a data-bound property. This enables multiple DataTemplates to be applied to the same type of object, to customize the appearance of particular objects.

1.Creating a DataTemplateSelector

A data template selector is implemented by creating a class that inherits from DataTemplateSelector. The OnSelectTemplate method is then overridden to return a particular DataTemplate.

You can refer the following code:

public class UrlTemplateSelector : DataTemplateSelector
{
    public DataTemplate ImageTemplate { get; set; }

    public DataTemplate VideoTemplate { get; set; }

    public DataTemplate OtherTemplate { get; set; }

    protected override DataTemplate OnSelectTemplate(object item, BindableObject container)
    {
        ItemModel model = (ItemModel)item;

        if (model.Url.EndsWith(".mp4")|| model.Url.EndsWith(".avi")|| model.Url.EndsWith(".rmvb")) // you can add multiple video file suffixes
        {
            return VideoTemplate;

        }
        else if (model.Url.EndsWith(".png")|| model.Url.EndsWith(".bmp") || model.Url.EndsWith(".jpg"))//you can add multiple image file suffixes
        {
            return ImageTemplate;
        }
        else {
            return OtherTemplate;
        }
    }
}

Suppose ItemModel is the binded item.

public class ItemModel
{
    public string Name { get; set; }
    public string Url { get; set; }
}

2. Usage(suppose the page is TestPage)

TestPage.xaml

<ContentPage.Resources>
    <ResourceDictionary>
        <DataTemplate x:Key="imageTemplate">
            <ViewCell>
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="0.4*" />
                        <ColumnDefinition Width="0.6*" />
                    </Grid.ColumnDefinitions>
                    <Label Text="{Binding Name}" TextColor="Green" FontAttributes="Bold" />
                    <Image Grid.Column="1" Source="{Binding Url}"  />
                </Grid>
            </ViewCell>
        </DataTemplate>
        <DataTemplate x:Key="videoTemplate">
            <ViewCell>
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="0.4*" />
                        <ColumnDefinition Width="0.6*" />
                    </Grid.ColumnDefinitions>
                    <Label Text="{Binding Name}" TextColor="Red" FontAttributes="Bold" />
                <behaviors:MediaElement  Grid.Column="1" Source="{Binding Url}"  />
                </Grid>
            </ViewCell>
        </DataTemplate>
    <local:UrlTemplateSelector x:Key="mediaUrlTemplateSelector" ImageTemplate="{StaticResource imageTemplate}" VideoTemplate="{StaticResource videoTemplate}" />
    </ResourceDictionary>
</ContentPage.Resources>
<StackLayout Margin="20">
    <Label Text="ListView with a DataTemplateSelector" FontAttributes="Bold" HorizontalOptions="Center" />
<ListView x:Name="listView" Margin="0,20,0,0" ItemTemplate="{StaticResource mediaUrlTemplateSelector}" />
</StackLayout>

For more details, you can check:https://docs.microsoft.com/en-us/xamarin/xamarin-forms/app-fundamentals/templates/data-templates/selector.

And there is a sample included in above document, you can try it.