if (m.Properties["Name"].Value.ToString() == shareName)

m.Properties["Path"]

private static string GetLocalSharePath(string shareName)
        {
            string wmiQuery = "SELECT * FROM Win32_Share";
            var managementObjectSearcher = new ManagementObjectSearcher(wmiQuery);

            foreach (ManagementObject m in managementObjectSearcher.Get())
            {
                if (m.Properties["Name"].Value.ToString() == shareName)
                    return m.Properties["Path"].Value.ToString();
            }
            return string.Empty;
        }

Console.WriteLine(  GetLocalSharePath("temp"));