how antivirus make a connection of uploded files?

I have writen a code in .net which scans the attched file before uploading to the server.
 
for this i make a .bat file
cd\Program Files\CA\SharedComponents\ScanEngine
Inocmd32.exe -arc -nex -sfi -nos -LIS:c:\%1.txt %2
cd\
type %1.txt
 
and call this .bat file through .net(c#) as
protected void Button2_Click(object sender, EventArgs e)
    {
        string dir = "C:\\files_upload";
        string[] files;
        int numFiles;
        files = Directory.GetFiles(dir);
        numFiles = files.Length;
        file_no = numFiles + 1;
        if (FileUpload1.HasFile)
     & ...