在ListView中顯示影像

我拼命地試圖在運行時用下載的圖形填充我的 ListView。到目前為止，我已經嘗試了幾種方法，但我無法讓它正常作業。

下載并自行顯示（我在一個名為 pic 的畫布中進行了測驗，因此代碼中仍有片段）作業正常，但 ListView 不會顯示該死的影像。

C#代碼：

    private async void LoadFlags(RootAutomarken automarken)
            {
                Image flag = new Image();
                var client = new HttpClient();
                foreach (var item in automarken.Automarken)
                {
                    flag = await LoadFlag(item.Land, client);
                    mainList.Items.Add(new CarListItem { Logo = flag, Name = item.Name, Land = item.Land, Region = item.Region});
                }
            }
    
    
    private async Task<Image> LoadFlag(string countrycode, HttpClient client)
            {
                var request = new HttpRequestMessage
                {
                    Method = HttpMethod.Get,
                    RequestUri = new Uri("https://www.countryflagsapi.com/png/"   countrycode),
                };
                using (var response = await client.SendAsync(request))
                {
                    response.EnsureSuccessStatusCode();
                    Stream imageStreamSource = await response.Content.ReadAsStreamAsync();
                    PngBitmapDecoder decoder = new PngBitmapDecoder(imageStreamSource, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.Default);
                    BitmapSource bitmapSource = decoder.Frames[0];

                    // Draw the Image
                    Image myImage = new Image();
                    myImage.Source = bitmapSource;
                    myImage.Stretch = Stretch.Uniform;
                    myImage.Height = 15;
                    myImage.Width = 15;
                    myImage.Margin = new Thickness(20);

                    pic.Children.Add(myImage);
                    return myImage;
                }

XAML：

    <Window.Resources>
        <Style TargetType="GridViewColumnHeader">
            <Setter Property="Background" Value="#505050" />
            <Setter Property="Foreground" Value="#FFDADADA" />
            <Setter Property="BorderBrush" Value="#606060" />
        </Style>
    </Window.Resources>
    <Grid>
        <ListView x:Name="mainList" Background="#202020" Margin="20,100,20,10" BorderBrush="#505050" Foreground="#FFDADADA">
            <ListView.View>
                <GridView>
                    <GridViewColumn Header="Logo" Width="50">
                        <GridViewColumn.CellTemplate>
                            <DataTemplate>
                                <Image Source="{Binding Logo}"/>
                            </DataTemplate>
                        </GridViewColumn.CellTemplate>
                    </GridViewColumn>
                    <GridViewColumn Header="Name" DisplayMemberBinding="{Binding Name}" Width="565"/>
                    <GridViewColumn Header="Land" DisplayMemberBinding="{Binding Land}" Width="50"/>
                    <GridViewColumn Header="Region" DisplayMemberBinding="{Binding Region}" Width="50"/>
                </GridView>
            </ListView.View>
        </ListView>
        <Canvas x:Name="pic"></Canvas>
    </Grid>

uj5u.com熱心網友回復：

您正在嘗試將Source一個元素的屬性Image（在 XAML 中）系結到另一個Image元素（在代碼中創建）。那是行不通的。

不要Image在視圖模型代碼中使用該型別。Image是一個視圖元素。

將屬性的型別和 to方法Logo的回傳型別更改為.LoadFlagImageSource

private static async Task<ImageSource> LoadFlag(
    string countrycode, HttpClient client)
{
    using var response = await client.GetAsync(
        $"https://www.countryflagsapi.com/png/{countrycode}");

    response.EnsureSuccessStatusCode();

    using var stream = await response.Content.ReadAsStreamAsync();

    return BitmapFrame.Create(stream,
        BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.OnLoad);
}

...

ImageSource flag = await LoadFlag(item.Land, client);

mainList.Items.Add(new CarListItem { Logo = flag, ... });

并像這樣系結它：

<Image Width="15" Height="15" Margin="20" Source="{Binding Logo}"/>

uj5u.com熱心網友回復：

您不能將Source一個元素的屬性系結Image到另一個Image元素。

嘗試這個：

<GridViewColumn.CellTemplate>
    <DataTemplate>
        <ContentControl Content="{Binding Logo}" />
    </DataTemplate>
</GridViewColumn.CellTemplate>

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