PasteDivCommon.razor

@using System.IO;
@inject IFileReaderService fileReaderService;

<div>

    Paste files on to this div 
    <div 
        style="width: 200px; height: 100px; background-color: azure; border-color: aquamarine; border-width: 2px; border-style: dashed" 
        @ref=pasteTargetElement
        @onpaste=OnPaste>

    </div>


    @foreach (var fileInfo in FileList)
    {
        <br />@fileInfo.Name
    }
</div>




<input id="additivediv" type="checkbox" checked=@Additive @onchange=OnAdditiveChange />
<label for="additivediv">Additive</label>
<br />
<button @onclick="Read" class="btn btn-primary">Read file</button>
<button @onclick="Clear" class="btn btn-primary">Clear</button>
<br /><br />
<textarea style="max-width: 100%;" cols="50" rows="20">@Output</textarea>
@code {
    ElementReference pasteTargetElement;
    IFileReaderRef pasteReference;
    IFileReaderRef ipReference;
    bool Additive { get; set; }
    
    string Output { get; set; }
    List<IFileInfo> FileList { get; } = new List<IFileInfo>();

    protected override async Task OnAfterRenderAsync(bool isFirstRender)
    {
        if (isFirstRender)
        {
            pasteReference = fileReaderService.CreateReference(pasteTargetElement);
            await pasteReference.RegisterPasteEventAsync();
        }
    }

    public async Task OnAdditiveChange(ChangeEventArgs e)
    {
        Additive = (bool)e.Value;
        StateHasChanged();
        await pasteReference.UnregisterPasteEventAsync();
        await pasteReference.RegisterPasteEventAsync(Additive);
    }

    public async Task Clear()
    {
        await pasteReference.ClearValue();
        await this.RefreshFileList();
    }
    
    public async Task OnPaste(EventArgs e)
    {
        Output += "Pasted a file.";
        this.StateHasChanged();
        await this.RefreshFileList();
    }

    private async Task RefreshFileList()
    {
        FileList.Clear();
        foreach (var file in await pasteReference.EnumerateFilesAsync())
        {
            var fileInfo = await file.ReadFileInfoAsync();
            FileList.Add(fileInfo);
        }
        this.StateHasChanged();
    }

    public async Task Read() {
        await ReadFile(pasteReference);
    }
    public async Task ReadClick()
    {
        await ReadFile(ipReference);
    }

    public async Task ReadFile(IFileReaderRef list)
    {
        Output = string.Empty;
        this.StateHasChanged();
        var nl = Environment.NewLine;
        foreach (var file in await list.EnumerateFilesAsync())
        {
            var fileInfo = await file.ReadFileInfoAsync();
            Output += $"{nameof(IFileInfo)}.{nameof(fileInfo.Name)}: {fileInfo.Name}{nl}";
            Output += $"{nameof(IFileInfo)}.{nameof(fileInfo.Size)}: {fileInfo.Size}{nl}";
            Output += $"{nameof(IFileInfo)}.{nameof(fileInfo.Type)}: {fileInfo.Type}{nl}";
            Output += $"{nameof(IFileInfo)}.{nameof(fileInfo.LastModifiedDate)}: {fileInfo.LastModifiedDate?.ToString() ?? "(N/A)"}{nl}";
            Output += $"Reading file...";
            this.StateHasChanged();
            fileInfo.PositionInfo.PositionChanged += (s, e) => {
                Output += $"Read {e.PositionDeltaSinceAcknowledge}, {e.Position} / {fileInfo.Size} ({e.Percentage:0.00}%){nl}";
                this.StateHasChanged();
            };

            var bufferSize = 20480;
            using (var ps = new PositionStream())
            using (var fs = await file.OpenReadAsync())
            {
                await fs.CopyToAsync(ps, bufferSize);
                Output += $"Done reading file {fileInfo.Name}{nl}.";
            }
            this.StateHasChanged();
        }

    }
}