/// <summary>Empty the binding source table</summary>
public void Clear()
{
// Notify of the pending reset of the binding source table
ListChanging?.Invoke(this, new ListChgEventArgs <Type>(this, ListChg.PreReset, -1, default(Type)));
Count = 0;
// Notify of binding source data reset
ListChanging?.Invoke(this, new ListChgEventArgs <Type>(this, ListChg.Reset, -1, default(Type)));
}
public CollectionBase(Exchange exchange, Func <TValue, TKey> key_from)
{
Exchange = exchange;
Updated = new ConditionVariable <DateTimeOffset>(DateTimeOffset.MinValue);
m_data = new BindingDict <TKey, TValue> {
KeyFrom = key_from
};
m_data.CollectionChanged += (s, a) => CollectionChanged?.Invoke(this, a);
m_data.ListChanging += (s, a) => ListChanging?.Invoke(this, a);
}
/// <summary>Updates the data table based on current filter, sorting, etc.</summary>
public void Update(bool raise_events = true)
{
// Invalidate to cause an Invalidated event before every update
if (!UpdateRequired)
{
Invalidate();
}
UpdateRequired = false;
// No data source, no update
if (DB == null)
{
Count = 0;
Cache.Flush();
return;
}
// Check for threading issues
// TODO: this can take a long time. It needs to be asynchronous somehow
Debug.Assert(DB.AssertCorrectThread());
// Generate the new binding source table in a temp table allowing use
// of the previous table while the 'Filtering' is happening.
var tmp_table = TableName + "_TMP";
// Create the temporary table
using (var t = DB.NewTransaction())
{
DB.Execute($"drop table if exists {tmp_table}");
DB.Execute(
$"create table {tmp_table} (\n" +
" [Idx] integer primary key autoincrement,\n" +
" [Key] integer\n" +
")");
// Populate from the base table using the filters
var join = Join ?? string.Empty;
var filter = Filter ?? string.Empty;
var orderby = OrderBy ?? string.Empty;
DB.Execute(
$"insert into {tmp_table} ([Key])\n" +
$"select {Pk} from {BaseTableName}\n" +
(join.Length != 0 ? $" join {join}" : "") +
(filter.Length != 0 ? $"{(join.Contains(" where ") ? " and " : " where ")} {filter}" : "") +
(orderby.Length != 0 ? $" order by {orderby}" : ""));
t.Commit();
}
// Notify of the pending reset of the binding source table
if (raise_events)
{
ListChanging?.Invoke(this, new ListChgEventArgs <Type>(this, ListChg.PreReset, -1, default(Type)));
}
// Drop the old table and rename the temporary table to the new binding source table
using (var t = DB.NewTransaction())
{
DB.Execute($"drop table if exists {TableName}");
DB.Execute($"alter table {tmp_table} rename to {TableName}");
t.Commit();
}
// Get the new table count
Count = DB.ExecuteScalar($"select count(*) from {TableName}");
Cache.Flush();
// Notify of binding source data reset
if (raise_events)
{
ListChanging?.Invoke(this, new ListChgEventArgs <Type>(this, ListChg.Reset, -1, default(Type)));
}
}
private void OnReseting()
{
ListChanging?.Invoke(this, new ListChangingEventArgs <MessageTraceItem>(ListChangingType.Clearing, null));
}
protected virtual void OnListChanging(ListChgEventArgs <TValue> args)
{
ListChanging?.Invoke(this, args);
}
