Add ApplyNullValues setting / implementation - makes it assign (rather than...

Add ApplyNullValues setting / implementation - makes it assign (rather than ignore) null values when possible; also nameof *all the things*; well... most of them

Dapper.Tests/Tests.Nulls.cs

+using Xunit;
+using System.Linq;
+namespace Dapper.Tests
+{
+    public partial class TestSuite
+    {
+        [Fact]
+		public void TestNullableDefault()
+        {
+            TestNullable(false);
+        }
+        [Fact]
+        public void TestNullableApplyNulls()
+        {
+            TestNullable(true);
+        }
+		private void TestNullable(bool applyNulls)
+        {
+            bool oldSetting = SqlMapper.Settings.ApplyNullValues;
+			try
+            {
+                SqlMapper.Settings.ApplyNullValues = applyNulls;
+                SqlMapper.PurgeQueryCache();
+
+                var data = connection.Query<NullTestClass>(@"
+declare @data table(Id int not null, A int null, B int null, C varchar(20), D int null, E int null)
+insert @data (Id, A, B, C, D, E) values 
+	(1,null,null,null,null,null),
+	(2,42,42,'abc',2,2)
+select * from @data").ToDictionary(_ => _.Id);
+
+                var obj = data[2];
+
+                obj.Id.IsEqualTo(2);
+                obj.A.IsEqualTo(42);
+                obj.B.IsEqualTo(42);
+                obj.C.IsEqualTo("abc");
+                obj.D.IsEqualTo(AnEnum.A);
+                obj.E.IsEqualTo(AnEnum.A);
+
+                obj = data[1];
+                obj.Id.IsEqualTo(1);
+                if (applyNulls)
+                {
+                    obj.A.IsEqualTo(2); // cannot be null
+                    obj.B.IsEqualTo(null);
+                    obj.C.IsEqualTo(null);
+                    obj.D.IsEqualTo(AnEnum.B);
+                    obj.E.IsEqualTo(null);
+                }
+				else
+                {
+                    obj.A.IsEqualTo(2);
+                    obj.B.IsEqualTo(2);
+                    obj.C.IsEqualTo("def");
+                    obj.D.IsEqualTo(AnEnum.B);
+                    obj.E.IsEqualTo(AnEnum.B);
+                }
+            } finally
+            {
+                SqlMapper.Settings.ApplyNullValues = oldSetting;
+            }
+        }
+
+		class NullTestClass
+        {
+			public int Id { get; set; }
+			public int A { get; set; }
+            public int? B { get; set; }
+            public string C { get; set; }
+            public AnEnum D { get; set; }
+            public AnEnum? E { get; set; }
+            
+			public NullTestClass()
+            {
+                A = 2;
+                B = 2;
+                C = "def";
+                D = AnEnum.B;
+                E = AnEnum.B;
+            }
+        }
+    }
+}

Dapper/SqlDataRecordListTVPParameter.cs

@@ -23,7 +23,7 @@ public SqlDataRecordListTVPParameter(IEnumerable<Microsoft.SqlServer.Server.SqlD
         static readonly Action<System.Data.SqlClient.SqlParameter, string> setTypeName;
         static SqlDataRecordListTVPParameter()
         {
-            var prop = typeof(System.Data.SqlClient.SqlParameter).GetProperty("TypeName", BindingFlags.Instance | BindingFlags.Public);
+            var prop = typeof(System.Data.SqlClient.SqlParameter).GetProperty(nameof(System.Data.SqlClient.SqlParameter.TypeName), BindingFlags.Instance | BindingFlags.Public);
             if (prop != null && prop.PropertyType == typeof(string) && prop.CanWrite)
             {
                 setTypeName = (Action<System.Data.SqlClient.SqlParameter, string>)

Dapper/SqlMapper.Settings.cs

@@ -18,12 +18,18 @@ static Settings()
             public static void SetDefaults()
             {
                 CommandTimeout = null;
+                ApplyNullValues = false;
             }
 
             /// <summary>
             /// Specifies the default Command Timeout for all Queries
             /// </summary>
             public static int? CommandTimeout { get; set; }
+
+            /// <summary>
+            /// Indicates whether nulls in data are silently ignored (default) vs actively applied and assigned to members
+            /// </summary>
+            public static bool ApplyNullValues { get; set; }
         }
     }
 }