public class CustomMsSql2008FeatureLayer : MsSql2008FeatureLayer
    {
        public CustomMsSql2008FeatureLayer(string connectionString, string tableName, string featureIdColumn)
            : base()
        {
            FeatureSource = new CustomMsSql2008FeatureSource(connectionString, tableName, featureIdColumn);
        }
    }

    public class CustomMsSql2008FeatureSource : MsSql2008FeatureSource
    {
        public CustomMsSql2008FeatureSource(string connectionString, string tableName, string featureIdColumn)
        {
            this.ConnectionString = connectionString;
            this.TableName = tableName;
            this.FeatureIdColumn = featureIdColumn;
            this.CommandTimeout = 30;
            this.Srid = 4326;
            this.WhereClause = string.Empty;
        }

        public string WkbFieldName
        {
            get;
            set;
        }

        protected override Collection<FeatureSourceColumn> GetColumnsCore()
        {
            string sqlStatement = "SELECT allColumns.name, allTypes.name, allTypes.max_length FROM sys.columns allColumns, sys.all_views allViews, sys.types allTypes where allColumns.object_id=allViews.object_id AND allColumns.user_type_id=allTypes.user_type_id AND allViews.name='" + TableName + "';";

            SqlCommand command = null;
            SqlDataReader dataReader = null;
            Collection<FeatureSourceColumn> columnCollection = new Collection<FeatureSourceColumn>();

            try
            {
                command = GetSqlCommand(sqlStatement, ExecutingSqlStatementType.GetColumns);

                dataReader = command.ExecuteReader();

                if (dataReader.HasRows)
                {
                    while (dataReader.Read())
                    {
                        string columnName = dataReader[0].ToString();
                        string typeName = dataReader[1].ToString();
                        int maxLength = Convert.ToInt32(dataReader[2], CultureInfo.InvariantCulture);
                        FeatureSourceColumn column = new FeatureSourceColumn(columnName, typeName, maxLength);
                        columnCollection.Add(column);
                    }
                }
                else
                {
                    if (dataReader != null)
                    {
                        dataReader.Dispose();
                    }
                    command.CommandText = string.Format(CultureInfo.InvariantCulture, "select * from {0} where 1=0;", TableName);
                    DataTable dataTable = new DataTable();
                    dataTable.Locale = CultureInfo.InvariantCulture;
                    SqlDataAdapter adpter = new SqlDataAdapter(command);
                    adpter.Fill(dataTable);
                    foreach (DataColumn column in dataTable.Columns)
                    {
                        string columnName = column.ColumnName;
                        string typeName = column.DataType.Name;
                        int maxLength = column.MaxLength;
                        if (columnName == WkbFieldName)
                        {
                            typeName = "geometry";
                        }
                        FeatureSourceColumn featureColumn = new FeatureSourceColumn(columnName, typeName, maxLength);
                        columnCollection.Add(featureColumn);
                    }
                    adpter.Dispose();
                    dataTable.Dispose();
                }
            }
            finally
            {
                if (command != null)
                {
                    command.Connection.Close();
                    command.Dispose();
                }
                if (dataReader != null)
                {
                    dataReader.Dispose();
                }
            }

            return columnCollection;
        }

        private SqlCommand GetSqlCommand(string sqlStatement, ExecutingSqlStatementType sqlStatementType)
        {
            if (sqlStatementType != ExecutingSqlStatementType.GetSpatialDataType
                && sqlStatementType != ExecutingSqlStatementType.GetColumns
                && sqlStatementType != ExecutingSqlStatementType.BuildIndex
                && sqlStatementType != ExecutingSqlStatementType.GetBoundingBox)
            {
                if (!string.IsNullOrEmpty(WhereClause))
                {
                    sqlStatement = sqlStatement.Replace(';', ' ');
                    if (sqlStatement.ToUpper(CultureInfo.InvariantCulture).Contains("WHERE"))
                    {
                        sqlStatement = sqlStatement + " " + WhereClause.ToUpper(CultureInfo.InvariantCulture).Replace("WHERE", "AND");
                    }
                    else
                    {
                        sqlStatement = sqlStatement + " " + WhereClause;
                    }
                    sqlStatement += ";";
                }
            }

            ExecutingSqlStatementMsSql2008FeatureSourceEventArgs e = new ExecutingSqlStatementMsSql2008FeatureSourceEventArgs(sqlStatement, sqlStatementType);
            OnExecutingSqlStatement(e);

            SqlConnection connection = new SqlConnection(ConnectionString);
            connection.Open();

            SqlCommand command = new SqlCommand(e.SqlStatement, connection);
            command.CommandTimeout = CommandTimeout;

            return command;
        }
    }