Added support for code contracts (requires VS support!)

Implemented Contracts into existing classes (yet incomplete especially with Interface implementations in NavObject). Otherwise it basically works.

NAVSCM Library/NavInterface/DevEnvInterface.cs

@@ -0,0 +1,81 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.IO;
+using System.Diagnostics.Contracts;
+
+namespace NavScm.NavInterface
+{
+    /// <summary>
+    /// Interfaces to the NAV IDE command line interface to export / import objects.
+    /// </summary>
+    /// <remarks>
+    /// <para>The interface is based on the powershell snippets delivered with NAV. 
+    /// Note, that the devenv does not give any return values. Instead, errors can only
+    /// be detected by the existance of the log file, which is created only upon errors.</para>
+    /// <para>Currently, the interface expects to be able to access the database using
+    /// NTLM Single Sign on. SQL user/pass authentication is not supported.</para>
+    /// </remarks>
+    class DevEnvInterface
+    {
+        private static readonly log4net.ILog log = log4net.LogManager.GetLogger(typeof(DevEnvInterface));
+
+        /// <summary>
+        /// Path to the dev env executable.
+        /// </summary>
+        protected string DevEnvPath { get; private set; }
+
+        /// <summary>
+        /// Hostname of the database server.
+        /// </summary>
+        protected string DatabaseServer { get; private set; }
+
+        /// <summary>
+        /// Name of the database itself.
+        /// </summary>
+        protected string DatabaseName { get; private set; }
+
+        /// <summary>
+        /// Create an interface class to a given NAV developer environment.
+        /// </summary>
+        /// <param name="devEnvPath">Full path and name to finsql.exe (or however you call it).</param>
+        public DevEnvInterface(string devEnvPath, string databaseServer, string databaseName)
+        {
+            Contract.Requires(devEnvPath != "");
+            Contract.Requires(databaseServer != "");
+            Contract.Requires(databaseName != "");
+            Contract.Ensures(File.Exists(DevEnvPath));
+            Contract.Ensures(databaseName == DatabaseName);
+            Contract.Ensures(databaseServer == DatabaseServer);
+            Contract.Ensures(devEnvPath == DevEnvPath);
+            
+            DevEnvPath = devEnvPath;
+            if (!File.Exists(DevEnvPath))
+                throw new InvalidOperationException($"The file {DevEnvPath} was not found.");
+
+            DatabaseServer = databaseServer;
+            DatabaseName = databaseName;
+
+            if (log.IsDebugEnabled)
+            {
+                log.Debug($"Constructed and attached to DevEnv {DevEnvPath}");
+                log.Debug($"Using database [{DatabaseName}] on server {DatabaseServer}");
+            }
+        }
+
+        /// <summary>
+        /// Exports a given NAV object to disk.
+        /// </summary>
+        /// <param name="obj">The NAV object as taken from the SQL database or from the cache (doesn't matter).</param>
+        /// <param name="destinationFileName">The name of the destination file. The system ensures, that the file
+        /// ends with .txt, as finsql.exe deduces the export format from the destiation files extension (crap).</param>
+        public void Export(NavObject obj, string destinationFileName)
+        {
+            Contract.Requires(obj != null);
+            Contract.Requires(destinationFileName != "");
+        }
+
+    }
+}

NAVSCM Library/NavInterface/NavObject.cs

@@ -4,6 +4,7 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
+using System.Diagnostics.Contracts;
 
 namespace NavScm.NavInterface
 {
@@ -43,15 +44,21 @@ namespace NavScm.NavInterface
     /// <seealso cref="NavObjectType"/>
     partial class NavObject : IEquatable<NavObject>, IComparable, IComparable<NavObject>
     {
+        private static readonly log4net.ILog log = log4net.LogManager.GetLogger(typeof(NavObject));
+
         /// <summary>
         /// Validate restrictions on supported objects as outlined in the class description.
         /// </summary>
         partial void OnLoaded()
         {
+            Contract.Requires(Company_Name.Length == 0);
+            Contract.Requires(Type >= 0  && Type <= 9 && Type != 2 && Type != 4 );
+            /*
             if (Company_Name.Length > 0)
                 throw new InvalidOperationException($"The object {CacheKey} holds a variant with the company name {Company_Name}, which is unsupported");
             if (Type < 0 || Type == 2 || Type == 4 || Type > 9)
                 throw new InvalidOperationException($"The object type of {CacheKey} is unsupported");
+            */
         }
 
         /// <summary>
@@ -75,20 +82,15 @@ namespace NavScm.NavInterface
         /// </summary>
         public string CacheKey
         {
-            get {
-                return $"{Type}.{ID}";
-            }   
+            get { return $"{Type}.{ID}"; }   
         }
 
         /// <summary>
         /// Converts the Date and Time fields to a combined Date/Time value.
         /// </summary>
-        public DateTime Modified
+        public DateTime ModifiedDate
         {
-            get
-            {
-                return Date.Add(Time.TimeOfDay);
-            }
+            get { return Date.Add(Time.TimeOfDay); }
         }
 
         /// <summary>