Localize changes to AbstractStringType

Author: hazzik

src/NHibernate.Test/NHSpecificTest/GH2621Enum/Fixture.cs

@@ -7,15 +7,13 @@ public class Fixture : BugTestCase
 		[Test]
 		public void TestOk()
 		{
-			using (ISession s = OpenSession())
+			using (var s = OpenSession())
+			using (s.BeginTransaction())
 			{
-				using (ITransaction t = s.BeginTransaction())
-				{
-					var query = s.CreateQuery(@"
-							SELECT Name FROM NHibernate.Test.NHSpecificTest.GH2621Enum.ClassWithString ROOT WHERE ROOT.Kind = :kind");
-					query.SetParameter("kind", Kind.SomeKind);
-					Assert.DoesNotThrow(() => query.List());
-				}
+				var query = s.CreateQuery(
+					@"SELECT Name FROM NHibernate.Test.NHSpecificTest.GH2621Enum.ClassWithString ROOT WHERE ROOT.Kind = :kind");
+				query.SetParameter("kind", Kind.SomeKind);
+				Assert.DoesNotThrow(() => query.List());
 			}
 		}
 	}

src/NHibernate/Driver/MicrosoftDataSqlClientDriver.cs

@@ -75,9 +75,6 @@ public MicrosoftDataSqlClientDriver()
 		/// <inheritdoc />
 		public virtual void AdjustParameterForValue(DbParameter parameter, SqlType sqlType, object value)
 		{
-			if (value is Enum)
-				value = Enum.GetName(value.GetType(), value);
-
 			if (value is string stringVal)
 				switch (parameter.DbType)
 				{

src/NHibernate/Driver/SqlClientDriver.cs

@@ -320,9 +320,6 @@ public override bool SupportsMultipleQueries
 
 		public virtual void AdjustParameterForValue(DbParameter parameter, SqlType sqlType, object value)
 		{
-			if (value is Enum)
-				value = Enum.GetName(value.GetType(), value);
-
 			if (value is string stringVal)
 			{
 				switch (parameter.DbType)

src/NHibernate/Type/AbstractStringType.cs

@@ -58,14 +58,23 @@ public override void Set(DbCommand cmd, object value, int index, ISessionImpleme
 		{
 			var parameter = cmd.Parameters[index];
 
-			//Allow the driver to adjust the parameter for the value
-			session.Factory.ConnectionProvider.Driver.AdjustParameterForValue(parameter, SqlType, value);
+			if (value == null)
+			{
+				parameter.Value = DBNull.Value;
+			}
+			else
+			{
+				var stringValue = Convert.ToString(value);
+			
+				//Allow the driver to adjust the parameter for the value
+				session.Factory.ConnectionProvider.Driver.AdjustParameterForValue(parameter, SqlType, stringValue);
 
-			// set the parameter value before the size check, since ODBC changes the size automatically
-			parameter.Value = value;
+				// set the parameter value before the size check, since ODBC changes the size automatically
+				parameter.Value = stringValue;
 
-			if (parameter.Size > 0 && value != null && Convert.ToString(value).Length > parameter.Size)
-				throw new HibernateException("The length of the string value exceeds the length configured in the mapping/parameter.");
+				if (parameter.Size > 0 && stringValue.Length > parameter.Size)
+					throw new HibernateException("The length of the string value exceeds the length configured in the mapping/parameter.");
+			}
 		}
 
 		public override object Get(DbDataReader rs, int index, ISessionImplementor session)