--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/HowTo/DataAccess/ParamNullValue.cs	Thu Mar 27 21:46:09 2014 +0400
@@ -0,0 +1,31 @@
+using System;
+using NUnit.Framework;
+using BLToolkit.DataAccess;
+
+namespace HowTo.DataAccess
+{
+	[TestFixture]
+	public class ParamNullValue
+	{
+		public abstract class TestAccessor : DataAccessor
+		{
+			public abstract Person SelectByKey([/*[a]*/ParamNullValue/*[/a]*/(1)] int id);
+		}
+
+		[Test]
+		public void Test()
+		{
+			TestAccessor ta = DataAccessor.CreateInstance<TestAccessor>();
+
+			// Parameter id == 1 will be replaced with NULL
+			//
+			Person p1 = ta.SelectByKey(1);
+			Assert.IsNull(p1);
+
+			// Parameter id == 2 will be send as is
+			//
+			Person p2 = ta.SelectByKey(2);
+			Assert.IsNotNull(p2);
+		}
+	}
+}