Getting Hash from command line arguments

Question

I am trying to create a console or form where you would drag a file onto their respective .exe The program would get that file and hash it, then set the clipboard text to the proviously generated hash.

This is my code

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography;
using System.Windows.Forms;
using System.IO;

namespace ConsoleApplication1
{
class Program
{
    static void Main(string[] args)
    {
        string path = args[0];          
        StreamReader wer = new StreamReader(path.ToString());
        wer.ReadToEnd();
        string qwe = wer.ToString();
        string ert = Hash(qwe);
        string password = "~" + ert + "~";
        Clipboard.SetText(password);
    }

    static public string Hash(string input)
    {
        MD5 md5 = MD5.Create();
        byte[] inputBytes = Encoding.ASCII.GetBytes(input);
        byte[] hash = md5.ComputeHash(inputBytes);
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < hash.Length; i++)
        {
            sb.Append(hash[i].ToString("X2"));
        }
        return sb.ToString();
    }
}
}

When I get the single .exe from the release, and drag a file onto it, I get some sort of threading error- I can't provide it because it is in the console, not in vb2010. Thanks for any help

Answer 1

Clipboard API uses OLE internally and thus can only be called on a STA thread. Unlike WinForms applications, console applications aren't using STA by default.

Add the [STAThread] attribute to Main:

[STAThread]
static void Main(string[] args)
{
    ...

Just do what the exception message told you to:

Unhandled Exception: System.Threading.ThreadStateException: Current thread must be set to single thread apartment (STA) mode before OLE calls can be made. Ensure that your Main function has STAThreadAttribute marked on it.

---

Cleaning up your program a bit:

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Windows.Forms;

namespace HashToClipboard
{
    class Program
    {
        [STAThread]
        static void Main(string[] args)
        {
            string hexHash = Hash(args[0]);
            string password = "~" + hexHash + "~";
            Clipboard.SetText(password);
        }

        static public string Hash(string path)
        {
            using (var stream = File.OpenRead(path))
            using (var hasher = MD5.Create())
            {
                byte[] hash = hasher.ComputeHash(stream);
                string hexHash = BitConverter.ToString(hash).Replace("-", "");
                return hexHash;
            }
        }
    }
}

This has several advantages over your program:

• It doesn't need to load the whole file into RAM at the same time
• It returns the correct result if the file contains non-ASCII characters/bytes
• It'd shorter and cleaner