TaikoLocalServer/TaikoWebUI/Pages/Dialogs/UserQrCodeDialog.razor

<MudDialog Class="dialog-user-qr-code">
    <DialogContent>
        <MudExtensions.MudBarcode Value="@qrCode" BarcodeFormat="ZXing.BarcodeFormat.QR_CODE" Height="300" Width="300" />
    </DialogContent>
    <DialogActions>
        <MudButton Color="Color.Primary" OnClick="Submit">@Localizer["Dialog OK"]</MudButton>
    </DialogActions>
</MudDialog>

@code {

    [CascadingParameter]
    MudDialogInstance MudDialog { get; set; } = null!;

    [Parameter]
    public User User { get; set; } = new();

    private string qrCode = string.Empty;

    protected override void OnInitialized()
    {
        base.OnInitialized();
        qrCode = "BNTTCNID" + User.AccessCodes.First();
    }

    private void Submit()
    {
        MudDialog.Close(DialogResult.Ok(true));
    }
}