/// <summary>
/// Initializes a new instance of the <Typ>LearningStoreQuerySort</Typ> class.
/// </summary>
/// <param name="column"></param>
/// <param name="direction"></param>
public LearningStoreQuerySort(LearningStoreViewColumn column, LearningStoreSortDirection direction)
{
// Check the parameters
if (column == null)
{
throw new LearningComponentsInternalException("LSTR2220");
}
m_column = column;
m_direction = direction;
}
/// <summary>
/// Add a sort order for the returned data
/// </summary>
/// <param name="columnName">Name of the column to be sorted on. This must
/// refer to a non-XML, non-Guid column.</param>
/// <param name="direction">Direction for the sort.</param>
/// <exception cref="ArgumentNullException"><paramref name="columnName"/> is a null reference.</exception>
/// <exception cref="ArgumentOutOfRangeException"><paramref name="direction"/> is invalid.</exception>
/// <exception cref="InvalidOperationException">
/// The column was not found or is not sortable</exception>
/// <example>
/// The following code creates a new query that returns the names of
/// all the users in the system sorted by name:
/// <code language="C#">
/// LearningStoreQuery query = store.CreateQuery("UserItemView");
/// query.AddColumn("Name");
/// query.AddSort("Name", LearningStoreSortDirection.Ascending);
/// </code>
/// </example>
public void AddSort(string columnName, LearningStoreSortDirection direction)
{
// Check input parameters
if (columnName == null)
{
throw new ArgumentNullException("columnName");
}
if ((direction != LearningStoreSortDirection.Ascending) &&
(direction != LearningStoreSortDirection.Descending))
{
throw new ArgumentOutOfRangeException("direction");
}
// Find the column in the view
LearningStoreViewColumn column = null;
if (!m_view.TryGetColumnByName(columnName, out column))
{
throw new InvalidOperationException(
String.Format(CultureInfo.CurrentCulture, LearningStoreStrings.ColumnNotFound, columnName));
}
// Can't sort on some columns
if (!column.Sortable)
{
throw new InvalidOperationException(
LearningStoreStrings.ColumnCannotBeSorted);
}
// Verify that the same sort hasn't already been added
if (m_sorts.Exists(delegate(LearningStoreQuerySort otherSort)
{
return(Object.ReferenceEquals(column, otherSort.Column));
}))
{
throw new InvalidOperationException(
LearningStoreStrings.ColumnAlreadySortedOn);
}
// Add the sort
LearningStoreQuerySort sort = new LearningStoreQuerySort(
column, direction);
m_sorts.Add(sort);
}