How do I convert the database size from mega bytes to bytes or vice-versa?

Question

Basically I'm creating a replication application and I just need to figure out the database size and how much free space I have available on the D:\ drive.

If the database size is larger than the free space, then I need to alert the user.

This is what I have so far:

First I find out how much free space there is in the D drive.

DriveInfo di = new DriveInfo(@"D:\");

if (di.IsReady)
{
    freeSpace = di.TotalFreeSpace;
}

Then I get the size of the database I'm going to replicate:

dbSize = Database.GetDatabaseSize(ddlPublisherServer.Text, ddlPublisherDatabase.Text);

Here's the method that gets the size of the DB. I don't know if there's a better way to do this but the size comes with the "MB" string in it so I need to remove it.

public static long GetDatabaseSize(string server, string database)
{
     string finalConnString = Properties.Settings.Default.rawConnectionString.Replace("<<DATA_SOURCE>>", server).Replace("<<INITIAL_CATALOG>>", database);

      using (SqlConnection conn = new SqlConnection(finalConnString))
      {
          using (SqlCommand cmd = new SqlCommand("sp_spaceused", conn))
          {
              cmd.CommandType = CommandType.StoredProcedure;

              conn.Open();
              cmd.ExecuteNonQuery();

              using (SqlDataAdapter da = new SqlDataAdapter(cmd))
              {
                  using (DataSet ds = new DataSet())
                  {
                      da.Fill(ds);

                      var spaceAvailable = ds.Tables[0].Rows[0][1].ToString();

                      string freeSpace = spaceAvailable.Remove(spaceAvailable.Length - 3, 3);

                      return Convert.ToInt64(freeSpace);
                   }
              }
         }
     }
}

My question now is -

How do I go about converting bytes to mega bytes so I can compare the db size and the disk free space?

This is what I have but it's mega bytes and bytes so I need to do a conversion here.

if (dbSize > freeSpace)
{
     ClientScript.RegisterStartupScript(this.GetType(), "Insufficient Space", "alert('The database size is greater than the available space on the drive. Please make some room for the database in D drive of the subscriber server.');", true);
 }

Answer 1

Bytes to Megabytes = Bytes / (1024 * 1024)
Megabytes to Bytes = Megabytes * (1024 * 1024.0)

Be sure to account for integer division, thus the 1024.0 so a floating point number is used.

Answer 2

There are 1024 bytes in a kilobyte and 1024 kilobytes in a megabyte. So multiple your megabytes by 1024 * 1024 (to get bytes). Or else divide your bytes by 1024 * 1024 (to get megabytes).