What causes the 'file used by another process' exception in my file.MoveTo() method and how can I solve it?

i updated the project, now the part that reads qr is in a metod, i use IronOcr now to read the qr code because it helps improving image quality, i definetly cause a lock but i don't know how to solve it

public string leggiQrTramiteTesseract(string filename)
    {           
        imgAnteprima.Source = new BitmapImage(new Uri(filename));
        var input = new OcrInput((filename));
        input.DeNoise();
        input.Deskew();

        var ocrTesseract = new IronTesseract();
        ocrTesseract.Configuration.ReadBarCodes = true;
        var ocrResult = ocrTesseract.Read(input);
        input.Dispose();
                                                                          
        if (ocrResult.Barcodes.Length > 0)
        {
            var barcode = ocrResult.Barcodes[0];
            return barcode.ToString();
        }
        return "";  

The documentation for Image.FromFile() states:

> The file remains locked until the Image is disposed.

Which means your issue is likely resolved if you put the code that tries to move the file outside the using block that acquires the bitmap.

The Bitmap class is holding the file open via an internal stream. You need to dispose it first before moving the file.

You can also cleanup the code by merging branches and using File.Move and Path.Combine.

for (int i = 0;i<files.Count;i++)
{
    Result barcodeResult;
    using (Bitmap barcodeBitmap = (Bitmap)Bitmap.FromFile(files[i]))
    {
        var barcodeReader = new BarcodeReader();
        barcodeResult = barcodeReader.Decode(barcodeBitmap);
    }

    File.Move(files[i], date);
    if (barcodeResult != null)
    {
        date = DateTime.Now.ToString("dd_MM_yyyy_HH-mm-ss");
        date = Path.Combine(destDir, date);
        Directory.CreateDirectory(date);
    }
}

The logic itself is a bit suspect: I would have thought you would only want to move the file if the result was not null, and that you could therefore create the date value at the beginning of the if.