/// <summary>Removes from this file the MidiItem object at the specified index.</summary>
/// <param name="index">The index in this file's list of the MidiItem object to remove.</param>
public void RemoveItem(int index)
{
/* Determine how many bytes to remove from the array. If the item is chunk info, the entire
* chunk will be removed. If it is a track (MTrk) chunk, decrement the number of tracks.
*/
MidiItem item = this.Items[index];
int i, n = item.Size;
MidiChunkInfo chunkInfo = item as MidiChunkInfo;
if (chunkInfo != null)
{
n += chunkInfo.Length;
i = this.Bytes.Length - item.Offset;
if (n > i)
{
n = i;
}
if (chunkInfo.Type == MidiChunkInfo.TrackType)
{
--this.Header.NumberOfTracks;
}
}
/* If the item is an MTrk event with a nonzero delta-time, the total time of each subsequent
* event in the track/chunk will need to be adjusted accordingly (after this item is removed).
*/
MidiEvent mtrkEvent = item as MidiEvent;
int deltaTime = (mtrkEvent == null) ? 0 : mtrkEvent.DeltaTime;
/* Remove from the list all items whose offsets are within the range of data being removed. */
for (i = item.Offset + n; index < this.ItemCount && this.Items[index].Offset < i; this.Items.RemoveAt(index))
{
item = this.Items[index];
/* If the item being removed is a channel message/event that does not use running status, there
* should be a corresponding entry in the map of running statuses that needs to be removed.
*/
MidiChannelEvent channelEvent = item as MidiChannelEvent;
if (channelEvent != null && !channelEvent.RunningStatus)
{
this.RunningStatusMap.Remove(item.Offset);
}
/* If the item being removed is a meta-event representing a key signature, there should
* be a corresponding entry in the key signature map that also needs to be removed.
*/
MidiMetaEvent metaEvent = MidiFile.ItemToKeySignatureEvent(item);
if (metaEvent != null)
{
this.KeySignatureMap.Remove(metaEvent.TotalTime);
}
}
/* If applicable, cascade total time changes through all subsequent events in the track. */
this.AdjustTotalTimes(index, -deltaTime);
/* Remove the appropriate number of bytes from the array. */
this.Resize(-n, i, (chunkInfo == null) ? index : -1);
}
private static MidiMetaEvent ItemToKeySignatureEvent(MidiItem item)
{
MidiMetaEvent metaEvent = item as MidiMetaEvent;
if (metaEvent == null)
{
return(null);
}
return((metaEvent.Type == MidiMetaEvent.KeySignatureType) ? metaEvent : null);
}
/****************
* Constructors *
****************/
#region Protected Constructors
/// <summary>Initializes a new instance of the MidiItemDialog class.</summary>
/// <param name="item">MIDI item to edit, or null to create a new item.</param>
protected MidiItemDialog(MidiItem item)
{
this._ForNewItem = (item == null);
}