FillObject: Check if keys are Dbnull, so not set

ResolveForeignKeys: Check if key is set

Database-Attribute_System/Attributes/DbForeignObject.cs

@@ -26,14 +26,15 @@ namespace eu.railduction.netcore.dll.Database_Attribute_System.Attributes
             this._foreignKeyName = foreignKeyName;
         }
 
-        public void Init(FieldInfo fi, DbObject classAttribute)
+        public void Init(FieldInfo fi, DbObject classAttribute, DbObject foreignClassAttribute = null)
         {
             this.parentField = fi;
             this.classAttribute = classAttribute;
             this.foreignObjectType = fi.FieldType;
 
             // Init foreign-object class
-            DbObject foreignClassAttribute = ClassAction.Init(this.foreignObjectType);
+            if(foreignClassAttribute == null)
+                foreignClassAttribute = ClassAction.Init(this.foreignObjectType);
 
             // Check if something is weird
             if (foreignClassAttribute.primaryKeyAttributes.Count < 1) throw new InvalidOperationException($"'{foreignClassAttribute.parentClassType.Name}' does not have a primaryKey.");

Database-Attribute_System/Attributes/DbObject.cs

@@ -13,6 +13,7 @@ namespace eu.railduction.netcore.dll.Database_Attribute_System.Attributes
         public string _tableName;
 
         public Type parentClassType;
+        public ConstructorInfo parentCInfo;
 
         // All childrenAttributes
         public List<BaseAttribute> baseAttributes = new List<BaseAttribute>() { };
@@ -35,6 +36,8 @@ namespace eu.railduction.netcore.dll.Database_Attribute_System.Attributes
         public void Init(Type classType)
         {
             this.parentClassType = classType;
+            parentCInfo = classType.GetConstructor(Type.EmptyTypes);
+
             this._tableName = this._tableName ?? classType.Name;    // If no alternative table-name is specified, use the class-name
 
             // Iterate thru all fields
@@ -66,7 +69,10 @@ namespace eu.railduction.netcore.dll.Database_Attribute_System.Attributes
                     }
                     else if (fi.GetCustomAttribute(typeof(DbForeignObject), true) is DbForeignObject fobj)    // ForeignObjects
                     {
-                        fobj.Init(fi, this);
+                        if(fi.FieldType == this.parentClassType)    // Check if we are referencing ourselfes
+                            fobj.Init(fi, this, this);
+                        else
+                            fobj.Init(fi, this);
 
                         this.foreignObjectAttributes.Add(fobj);
                     }

Database-Attribute_System/ClassAction.cs

@@ -69,10 +69,16 @@ namespace eu.railduction.netcore.dll.Database_Attribute_System
                     if (baseAttribute._attributeName.ToLower() == data_keySet.Key.ToLower())
                     {
                         object value = data_keySet.Value;
-                        //if (baseAttribute.parentField.FieldType == typeof(Guid)) value = new Guid((string)value);   // If its a guid, i need to convert
+                        if (!(value is DBNull))     // Check if value is empty
+                        {
+                            //if (baseAttribute.parentField.FieldType == typeof(Guid)) value = new Guid((string)value);   // If its a guid, i need to convert
+
+                            baseAttribute.parentField.SetValue(classObject, value);
+                            break;
+                        }
+
+
 
-                        baseAttribute.parentField.SetValue(classObject, value);
-                        break;
                     }
                 }
             }
@@ -104,14 +110,14 @@ namespace eu.railduction.netcore.dll.Database_Attribute_System
         }
         public static T GetByPrimaryKey<T>(Type classType, Dictionary<string, object> primaryKeyData, Func<string, List<Dictionary<string, object>>> queryExecutor) where T: new()
         {
-            // Create new empty object
-            T obj = new T();
-
             // Read dbObject-attribute
             DbObject dbObject = ClassAction.Init(classType);
 
             if (dbObject.primaryKeyAttributes.Count < 1) throw new InvalidOperationException($"No primaryKey found in '{classType.Name}'");
 
+            // Create new empty object
+            T obj = (T)dbObject.parentCInfo.Invoke(null);
+
             // iterate thru them to check and fill object
             foreach (DbPrimaryKey primaryKeyAtt in dbObject.primaryKeyAttributes)
             {
@@ -295,13 +301,14 @@ namespace eu.railduction.netcore.dll.Database_Attribute_System
             // Resolve foreignObjects
             foreach (DbForeignObject foreignObjectAtt in dbObject.foreignObjectAttributes)
             {
+                object foreignKey_value = foreignObjectAtt.foreignKeyAttribute.parentField.GetValue(classObject);
                 object foreignObject_value = foreignObjectAtt.parentField.GetValue(classObject);
 
-                // When its empty, get it & set it
+                // When key is set and object is empty, get it & set it
-                if(foreignObject_value == null)
+                if(foreignKey_value != null && foreignObject_value == null)
                 {
                     // Resolve it
-                    foreignObject_value = GetByPrimaryKey<T>(classType, foreignObjectAtt.foreignKeyAttribute.parentField.GetValue(classObject), queryExecutor);
+                    foreignObject_value = GetByPrimaryKey<T>(foreignObjectAtt.foreignObjectType, foreignKey_value, queryExecutor);
                     foreignObjectAtt.parentField.SetValue(classObject, foreignObject_value);    // Set the value
 
                     // Now scan the just resolved class to be able to set myself