Add support for OrmLiteConfig.OnDbNullFilter

Author: mythz

src/ServiceStack.OrmLite/FieldDefinition.cs

@@ -27,6 +27,8 @@ public string FieldName
 
         public Type FieldType { get; set; }
 
+        public object FieldTypeDefaultValue { get; set; }
+
         public Type TreatAsType { get; set; }
 
         public Type ColumnType

src/ServiceStack.OrmLite/OrmLiteConfig.cs

@@ -184,6 +184,8 @@ public static IOrmLiteExecFilter ExecFilter
 
         public static Func<string, string> StringFilter { get; set; }
 
+        public static Func<FieldDefinition, object> OnDbNullFilter { get; set; }
+
         public static Func<string, string> SanitizeFieldNameForParamNameFn = fieldName =>
             (fieldName ?? "").Replace(" ", "");
     }

src/ServiceStack.OrmLite/OrmLiteConfigExtensions.cs

@@ -144,6 +144,7 @@ internal static ModelDefinition GetModelDefinition(this Type modelType)
                     Name = propertyInfo.Name,
                     Alias = aliasAttr != null ? aliasAttr.Name : null,
                     FieldType = propertyType,
+                    FieldTypeDefaultValue = propertyType.GetDefaultValue(),
                     TreatAsType = treatAsType,
                     PropertyInfo = propertyInfo,
                     IsNullable = isNullable,

src/ServiceStack.OrmLite/OrmLiteUtils.cs

@@ -374,14 +374,15 @@ public static bool HandledDbNullValue(FieldDefinition fieldDef, IDataReader data
             if (fieldDef == null || fieldDef.SetValueFn == null || colIndex == NotFound) return true;
             if (dataReader.IsDBNull(colIndex))
             {
-                if (fieldDef.IsNullable)
+                var value = fieldDef.IsNullable ? null : fieldDef.FieldTypeDefaultValue;
+                if (OrmLiteConfig.OnDbNullFilter != null)
                 {
-                    fieldDef.SetValueFn(instance, null);
-                }
-                else
-                {
-                    fieldDef.SetValueFn(instance, fieldDef.FieldType.GetDefaultValue());
+                    var useValue = OrmLiteConfig.OnDbNullFilter(fieldDef);
+                    if (useValue != null)
+                        value = useValue;
                 }
+
+                fieldDef.SetValueFn(instance, value);
                 return true;
             }
             return false;

tests/ServiceStack.OrmLite.Tests/OrmLiteExecFilterTests.cs

@@ -84,7 +84,7 @@ public void Can_mock_store_procedure()
             using (var db = OpenDbConnection())
             {
                 var person = db.SqlScalar<Person>("exec sp_name @firstName, @age",
-                    new {firstName = "aName", age = 1});
+                    new { firstName = "aName", age = 1 });
 
                 Assert.That(person.FirstName, Is.EqualTo("Mocked"));
             }
@@ -109,5 +109,26 @@ public void Does_use_StringFilter()
 
             OrmLiteConfig.StringFilter = null;
         }
+
+        [Test]
+        public void Does_use_StringFilter_on_null_strings()
+        {
+            OrmLiteConfig.OnDbNullFilter = fieldDef => 
+                fieldDef.FieldType == typeof(string)
+                    ? "NULL"
+                    : null;
+
+            using (var db = OpenDbConnection())
+            {
+                db.DropAndCreateTable<Poco>();
+
+                db.Insert(new Poco { Name = null });
+                var row = db.Select<Poco>().First();
+                
+                Assert.That(row.Name, Is.EqualTo("NULL"));
+            }
+
+            OrmLiteConfig.OnDbNullFilter = null;
+        }
     }
 }