radzen-blazor/RadzenBlazorDemos/Pages/FileInputByteArray.razor

<RadzenStack AlignItems="AlignItems.Center">
    <RadzenCard class="rz-m-0 rz-m-md-12" Style="width: 100%; max-width: 600px;">
        <RadzenFileInput @bind-Value=@photo @bind-FileName=@fileName @bind-FileSize=@fileSize TValue="byte[]" Style="width: 100%" 
            Change=@(args => OnChange(args, "FileInput")) Error=@(args => OnError(args, "FileInput")) InputAttributes="@(new Dictionary<string,object>(){ { "aria-label", "select file" }})"/>
    </RadzenCard>
</RadzenStack>

<EventConsole @ref=@console />

@code {
    EventConsole console;
    byte[] photo;

    string fileName;
    long? fileSize;

    void OnChange(byte[] value, string name)
    {
        console.Log($"{name} value changed");
    }

    void OnError(UploadErrorEventArgs args, string name)
    {
        console.Log($"{args.Message}");
    }
}