Can a Generic Method handle both Reference and Nullable Value types?

public static int? GetNullableInt32(this IDataRecord dr, int ordinal)
{
    int? nullInt = null;
    return dr.IsDBNull(ordinal) ? nullInt : dr.GetInt32(ordinal);
}

public static int? GetNullableInt32(this IDataRecord dr, string fieldname)
{
    int ordinal = dr.GetOrdinal(fieldname);
    return dr.GetNullableInt32(ordinal);
}

public static Nullable<T> GetNullable<T>(this IDataRecord dr, int ordinal)
{
    Nullable<T> nullValue = null;
    return dr.IsDBNull(ordinal) ? nullValue : (Nullable<T>) dr.GetValue(ordinal);
}

public static T GetNullable<T>(this IDataRecord dr, int ordinal)
{
    return dr.IsDBNull(ordinal) ? default(T) : (T) dr.GetValue(ordinal);
}

public static T Get<T>( this IDataRecord dr, int ordinal)
{
	T  nullValue = default(T);
	return dr.IsDBNull(ordinal) ? nullValue : (T) dr.GetValue(ordinal);
}


public void Code(params string[] args)
{
	IDataRecord dr= null;
	int? a = Get<int?>(dr, 1);
	string b = Get<string>(dr, 2);
}

private void Test()
{
  int? iTestA;
  int? iTestB;
  int iTestC;
  string sTestA;
  string sTestB;

  //Create connection
  using (SqlConnection oConnection = new SqlConnection(@""))
  {
    //Open connection
    oConnection.Open();

    //Create command
    using (SqlCommand oCommand = oConnection.CreateCommand())
    {
      //Set command text
      oCommand.CommandText = "SELECT null, 1, null, null, '1'";

      //Create reader
      using (SqlDataReader oReader = oCommand.ExecuteReader())
      {
        //Read the data
        oReader.Read();

        //Set the values
        iTestA = oReader[0] as int?;
        iTestB = oReader[1] as int?;
        iTestC = oReader[2] as int? ?? -1;
        sTestA = oReader[3] as string;
        sTestB = oReader[4] as string;
      }
    }
  }
}

public static T GetData<T>(this IDataReader reader, Func<int, T> getFunc, int index)
{
    if (!reader.IsClosed)
    {
        return getFunc(index);
    }
    throw new ArgumentException("Reader is closed.", "reader");
}

public static T GetDataNullableRef<T>(this IDataReader reader, Func<int, T> getFunc, int index) where T : class
{
    if (!reader.IsClosed)
    {
        return reader.IsDBNull(index) ? null : getFunc(index);
    }
    throw new ArgumentException("Reader is closed.", "reader");
}

public static T? GetDataNullableValue<T>(this IDataReader reader, Func<int, T> getFunc, int index) where T : struct
{
    if (!reader.IsClosed)
    {
        return reader.IsDBNull(index) ? (T?)null : getFunc(index);
    }
    throw new ArgumentException("Reader is closed.", "reader");
}

private static Whatever CreateObject(IDataReader reader)
{
    Int32? id = reader.GetDataNullableValue<Int32>(reader.GetInt32, 0);
    string name = reader.GetDataNullableRef<string>(reader.GetString, 1);
    Int32 x = reader.GetData<Int32>(reader.GetInt32, 2);
}

public static T Get<T>(this IDataRecord rec, Func<int, T> GetValue, int ordinal)
{
    return rec.IsDBNull(ordinal) ? default(T) : GetValue(ordinal);
}

public static T Get<T>(this IDataRecord rec, Func<IDataRecord, int, T> GetValue, int ordinal)
{
    return rec.IsDBNull(ordinal) ? default(T) : GetValue(rec, ordinal);
}

public static Func<IDataRecord, int, int> GetInt32 = (rec, i) => rec.GetInt32(i);
public static Func<IDataRecord, int, bool> GetBool = (rec, i) => rec.GetBoolean(i);
public static Func<IDataRecord, int, string> GetString = (rec, i) => rec.GetString(i);

rec.Get(GetString, index);
rec.Get(GetInt32, index);

DataRow record = GetSomeRecord();
int? someNumber = record[15] as int?
Guid? someUID = record["MyPrimaryKey"] as Guid?;
string someText = GetSomeText();
record["Description"] = someText.ToDbString();

// ........

public static class StringExtensionHelper {
    public static object ToDbString( this string text ) {
         object ret = null != text ? text : DBNull.Value
         return ret;
    }
}

public static class StringExtensionHelper {
    public static object ToDbValue( this object value ) {
         object ret = object.ReferenceEquals( value, null ) ? (object)DBNull.Value : value;
         return ret;
    }
}