Episode 1 here
Causing2
Reason for ListView showing Items of picture
ListView must have a List to show at MainViewModel(Binding Context) not only binding ItemSource at Xaml.
Solution
Add the code at MainViewModel then, bind ItemSource.
For your information, [ObserverProperty] can generate automatically to Capital G "GazouByte" at Xaml ItemSource from field gazouByte at MainV MainViewModel
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namespace WorkReview.ViewModels;
public partial class MainViewModel : ObservableObject
{
[ObservableProperty]
private string? statusMessage;[ObservableProperty]
private List<GazouByte>? gazouBytes; //here, List for MainPage[ObservableProperty]
private ImageSource? userPreview; //MainPageのプレビュー用
private string? gazouName; //ファイル名private byte[]? gazouBinary; //画像のバイナリデータ
private string? gazouExtension; //拡張子情報
public MainViewModel()
{ }[RelayCommand]
private void OnGetAllGazou() //画像リストの取得ボタン
{
GazouBytes = App.GazouByteRepo.GetAllGazouBytes();
StatusMessage = "got all file list"; StatusMessage = "got all file list";}
[RelayCommand]
private void OnFileSave()
{
if (gazouName == null) return;var gazouByte = new GazouByte
{
GazouName = gazouName!,
GazouBinary = gazouBinary!, //!はNull出ないことを宣言GazouExtension = gazouExtension!,
};App.GazouByteRepo.AddNewGazouByte(gazouByte);
StatusMessage = "file saved";
}
[RelayCommand]
private async Task OnFileSelect() //非同期でTaskとして結果を返す{
try
{
var result = await FilePicker.PickAsync();
if (result == null) return;
var fileName = result.FileName;if (fileName.EndsWith("jpg", StringComparison.OrdinalIgnoreCase) ||
fileName.EndsWith("png", StringComparison.OrdinalIgnoreCase))
{
using (var stream = await result.OpenReadAsync())
using (var memoryStream = new MemoryStream())
{
await stream.CopyToAsync(memoryStream);
gazouName = fileName;
gazouBinary = memoryStream.ToArray();
gazouExtension = result.ContentType;
var previewStream = new MemoryStream(memoryStream.ToArray());UserPreview = ImageSource.FromStream(() => previewStream);
}
}
else
{
StatusMessage = "Unsupported file type.";
}
}
catch (Exception ex)
{
StatusMessage = $"Error selecting file: {ex.Message}";
}
}
}
Afterword
As you can see from my past questions, I've been a bit of a pain with my inquiries. I'll try to be more considerate in the future.
I've realized I still have a lot to learn about MVVM and XAML.
But I was really impressed by how easily the people who answered my questions were able to solve problems I'd been stuck on for a week. I hope to be able to do that someday too.
I learned a lot just by asking questions, so thanks for that.
