C#Xamarin ImageURL [英] C# Xamarin ImageURL

问题描述

我有3个字段的模型:标题，正文，图片.

I have model with 3 fields : TItle, Body, Picture.

 public class Names
    {   [PrimaryKey]
        public string Title { get; set; }
        public string Body { get; set; }
        public string Picture { get; set; }}

图片"字段是一个字符串值，它是图片网址的一部分. 因此，真实的网址将如下所示:

Field 'Picture' is a string value which is a part of url of image. So real URL will looks like:

Source = Settings.ServerUrl + "/api/File/" + Picture

如何在xamarin中将此类URL用于imagecell的图像源?

How I can use such url for imagesource of imagecell in xamarin?

当前XAML的示例:

Example of current XAML:

当前XAML.CS的示例

Example of current XAML.CS

namespace Project.Mobile.Client.Portable.Views.Names
{
    [XamlCompilation(XamlCompilationOptions.Compile)]
    public partial class NamesListPage : ContentPage
    {
        public ObservableCollection<Models.Names> items { get; set; }

    public NewPage()
    {
        items = new ObservableCollection<Models.Names>();
        this.BindingContext = this;
        InitializeComponent();

        // Disabling selection
        Lst.ItemSelected += (sender, e) => {
            ((ListView)sender).SelectedItem = null;
        };

        Lst.Refreshing += (sender, e) => {
            LoadUsersData();
        };
        LoadUsersData();
    }

    public async void LoadUsersData()
    {
        Lst.IsRefreshing = true;

        var names = await App.Database.Names.GetItemsAsync();
        items.Clear();


        foreach (var item in names)
            items.Add(item);

        Lst.IsRefreshing = false;
    }

    public async void OnItemTapped(object sender, ItemTappedEventArgs e)
    {
        NamesReadPage readPage = new NamesReadPage();
        readPage.BindingContext = e.Item as Models.Names;

        await Navigation.PushAsync(readPage);
    }
}

由于代码限制，我将xaml代码添加为图像.抱歉.

I added xaml code as image because of code limit. Sorry for that.

推荐答案

通过IValueConverter

public class PictureURLConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return Settings.ServerUrl + "/api/File/" + (string)value;
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

添加IValueConverter的命名空间

xmlns:local="clr-namespace:SameNameSpace;assembly=SomeAssemblyName"    

将IValueConverter添加到您的ContentPage.Resources

<ContentPage.Resources>
    <ResourceDictionary>
        <local:PictureURLConverter x:Key="pictureURL"></local:PictureURLConverter>
    </ResourceDictionary>
</ContentPage.Resources>

在绑定中使用转换器

<Image Source="{Binding Picture, Converter={StaticResource pictureURL}}" />

这篇关于C#Xamarin ImageURL的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！