nhibernateGH-3530: The SqlServer 2008 driver does not support the DbD…

…ataReader.GetChar method, wrap it in a SqlServerDbDataReader.

src/NHibernate/AdoNet/SqlServerDbDataReader.cs

@@ -0,0 +1,26 @@
+using System;
+using System.Collections.Generic;
+using System.Data.Common;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace NHibernate.AdoNet
+{
+	public class SqlServerDbDataReader : DbDataReaderWrapper
+	{
+		public SqlServerDbDataReader(DbDataReader reader) : base(reader) { }
+
+		public override char GetChar(int ordinal)
+		{
+			// SQL Server does not support GetChar
+			var value = DataReader[ordinal];
+
+			return value switch
+			{
+				string s => s[0],
+				_ => (char) value
+			};
+		}
+	}
+}

src/NHibernate/Async/Driver/Sql2008ClientDriver.cs

@@ -0,0 +1,37 @@
+//------------------------------------------------------------------------------
+// <auto-generated>
+//     This code was generated by AsyncGenerator.
+//
+//     Changes to this file may cause incorrect behavior and will be lost if
+//     the code is regenerated.
+// </auto-generated>
+//------------------------------------------------------------------------------
+
+
+using System;
+using System.Data;
+using System.Data.Common;
+using NHibernate.Util;
+using NHibernate.AdoNet;
+
+namespace NHibernate.Driver
+{
+	using System.Threading.Tasks;
+	using System.Threading;
+	public partial class Sql2008ClientDriver : SqlClientDriver
+	{
+
+		#if NETFX
+		#else
+
+		#endif
+
+		public override async Task<DbDataReader> ExecuteReaderAsync(DbCommand command, CancellationToken cancellationToken)
+		{
+			cancellationToken.ThrowIfCancellationRequested();
+			var reader = await (command.ExecuteReaderAsync(cancellationToken)).ConfigureAwait(false);
+
+			return new SqlServerDbDataReader(reader);
+		}
+	}
+}

src/NHibernate/Driver/Sql2008ClientDriver.cs

@@ -2,10 +2,11 @@
 using System.Data;
 using System.Data.Common;
 using NHibernate.Util;
+using NHibernate.AdoNet;
 
 namespace NHibernate.Driver
 {
-	public class Sql2008ClientDriver : SqlClientDriver
+	public partial class Sql2008ClientDriver : SqlClientDriver
 	{
 		const byte MaxTime = 5;
 
@@ -34,5 +35,12 @@ protected override void InitializeParameter(DbParameter dbParam, string name, Sq
 
 		/// <inheritdoc />
 		public override DateTime MinDate => DateTime.MinValue;
+
+		public override DbDataReader ExecuteReader(DbCommand command)
+		{
+			var reader = command.ExecuteReader();
+
+			return new SqlServerDbDataReader(reader);
+		}
 	}
 }