檢測目錄下指定檔案md5

要做一個程序,檢測目錄下指定檔案的md5是否我指定的md5 , 已經做出檢測指定檔案的md5功能 , 但如何對比檢測出來的md5和我指定的string 呢? 我用了String.Compare 對比兩個string是否一致 , 但VS報錯了 , 可能是語法有錯 =__= ,請求大大幫幫忙指點指點。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace checkmd5
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            var tragetFile = new System.IO.FileStream(@"Minecraft.jar", System.IO.FileMode.Open);
            var md5 = new System.Security.Cryptography.MD5CryptoServiceProvider();
            byte[] hashbytes = md5.ComputeHash(tragetFile);
            tragetFile.Close();

            System.Text.StringBuilder checkmd5 = new System.Text.StringBuilder();
            for (int i = 0; i < hashbytes.Length; i++)
            {
                checkmd5.Append(hashbytes[i].ToString("x2"));
            }
            string MyString = checkmd5.ToString();
            string Minecraftjar = "4eca7879ff514cdd79c290701443eedd";
            MessageBox.Show(String.Compare(MyString, Minecraftjar ));
        }

    }
}