A SQL Extension to read JSON generated from SQL Server in C#

SQLExtension.cs

public static class SQLExtensions
{
    /// <summary>
    /// Microsoft doesn't handle JSON well, it wants to use XML methods which then retrieve
    /// the JSON. Sometimes the JSON has characters in it which 
    /// </summary>
    public static SqlJSONReader ExecuteJsonReader(this SqlCommand cmd)
    {
        var rdr = cmd.ExecuteReader();
        return new SqlJSONReader(rdr);
    }

    public static async Task<SqlJSONReader> ExecuteJsonReaderAsync(this SqlCommand cmd)
    {
        var rdr = await cmd.ExecuteReaderAsync();
        return new SqlJSONReader(rdr);
    }

    public class SqlJSONReader : System.IO.TextReader
    {
        private SqlDataReader SqlReader { get; set; }
        private string CurrentLine { get; set; }
        private int CurrentPostion { get; set; }

        public SqlJSONReader(SqlDataReader rdr)
        {
            CurrentLine = "";
            CurrentPostion = 0;
            this.SqlReader = rdr;
        }
        public override int Peek()
        {
            return GetChar(false);
        }

        public async Task<int> PeekAsync()
        {
            return await GetCharAsync(false);
        }

        public override int Read()
        {
            return GetChar(true);
        }

        public async Task<int> ReadAsync()
        {
            return await GetCharAsync(true);
        }

        public int GetChar(bool Advance)
        {
            while (CurrentLine.Length == CurrentPostion)
            {
                if (!SqlReader.Read())
                {
                    return -1;
                }
                CurrentLine = SqlReader.GetString(0);
                CurrentPostion = 0;
            }
            var rv = CurrentLine[CurrentPostion];
            if (Advance)
                CurrentPostion += 1;

            return rv;
        }

        public async Task<int> GetCharAsync(bool Advance)
        {
            while (CurrentLine.Length == CurrentPostion)
            {
                if ((await SqlReader.ReadAsync()) == false)
                {
                    return -1;
                }
                CurrentLine = SqlReader.GetString(0);
                CurrentPostion = 0;
            }
            var rv = CurrentLine[CurrentPostion];
            if (Advance)
                CurrentPostion += 1;

            return rv;
        }

        public string ReadAll()
        {
            var sbResult = new StringBuilder();

            if (SqlReader.HasRows)
            {
                while (SqlReader.Read())
                    sbResult.Append(SqlReader.GetString(0));

            }
            else
                return string.Empty;

            // Clean up any JSON escapes before returning
            return JsonConvert.DeserializeObject(sbResult.ToString()).ToString();
        }

        public async Task<string> ReadAllAsync()
        {
            var sbResult = new StringBuilder();

            if (SqlReader.HasRows)
            {
                while (await SqlReader.ReadAsync())
                    sbResult.Append(SqlReader.GetString(0));

            }
            else
                return string.Empty;

            // Clean up any JSON escapes before returning
            return JsonConvert.DeserializeObject(sbResult.ToString()).ToString();
        }

        public override void Close()
        {
            SqlReader.Close();
        }
    }

}