I have this two classes:

public sealed class MainClass
{
    private readonly IFileSaver _fileSaver;



    public MainClass()
    {
        _fileSaver = new FileSaver(@"D:file.csv");
    }


    public async Task SaveFileAsync(byte[] paramFile)
    {
        await _fileSaver.SaveAsync(paramFile);
    }
}





public class IFileSaver()
{
    public string Path { get; }

    public Task SaveAsync(byte[] paramBinaryFile);
}



public sealed class FileSaver()
{
    public string Path {get; }



    public FileSaver(string paramFilePath)
    {
        _path = paramFilePath;
    }


    public async Task SaveAsync(byte[] paramFile)
    {
        await File.WriteAllBytes(_path, paramFile);
    }
}

One main class that use the FileSaver to save a file.

In this case, I get an error, denied access.

If I don’t use the interface as the property in main class and I use the class FileSaver directly, it works.

Why when I use the interface it doesn’t work and it works when I don’t use it?

Thanks.