/// <summary>
/// Determines whether two <see cref="DragDropInfo"/> objects have the same settings.
/// </summary>
/// <param name="obj">The object to compare.</param>
/// <returns><c>true</c> if the two objects have the same settings, otherwise <c>false</c>.</returns>
public override bool Equals(object obj)
{
DragDropInfo other = obj as DragDropInfo;
if (obj != null)
{
return(Location == other.Location && KeyStates == other.KeyStates && Data == other.Data &&
AllowedEffects == other.AllowedEffects && IsInternal == other.IsInternal && Source == other.Source &&
VirtualBufferPosition == other.VirtualBufferPosition);
}
else
{
return(false);
}
}
/// <summary>
/// Determines whether the handler can accept data for a drag and drop operation.
/// </summary>
/// <param name="dragDropInfo">
/// Information about the drag and drop operation.
/// </param>
/// <returns><c>true</c> if the handler can accept data now, otherwise <c>false</c>.</returns>
/// <remarks>
/// <para>This method is used by the editor to check whether the drop handler can accept data
/// after it has been designated to handle a drag and drop operation. For example,
/// the drop handler may be able to handle data only if the view is not read-only.
/// The implementation of this method would check the read-only status of the view.</para>
/// <para>If one drop handler returns <c>false</c>,
/// another drop handler might be used to handle the drop operation, even if
/// the ordering of <see cref="IDropHandler"/> objects dictates otherwise.</para>
/// </remarks>
public virtual bool IsDropEnabled(DragDropInfo dragDropInfo)
{
if (dragDropInfo == null)
{
throw new ArgumentNullException(nameof(dragDropInfo));
}
//ensure the source allows either move or copy operation
if (!(
(dragDropInfo.AllowedEffects & NSDragOperation.Copy) == NSDragOperation.Copy ||
(dragDropInfo.AllowedEffects & NSDragOperation.Move) == NSDragOperation.Move))
{
return(false);
}
//only allow dropping when the view is not read-only
return(!_cocoaTextView.Options.GetOptionValue <bool>(DefaultTextViewOptions.ViewProhibitUserInputId));
}
/// <summary>
/// Determines what drag & drop effect should be displayed to the user based on the state of the operation.
/// </summary>
protected virtual DragDropPointerEffects GetDragDropEffect(DragDropInfo dragDropInfo)
{
if (dragDropInfo == null)
{
throw new ArgumentNullException(nameof(dragDropInfo));
}
VirtualSnapshotPoint dropPoint = dragDropInfo.VirtualBufferPosition.TranslateTo(_cocoaTextView.TextSnapshot);
//if an external drop is being performed on a read-only region, then disallow it
if (_cocoaTextView.TextBuffer.IsReadOnly(dropPoint.Position))
{
return(DragDropPointerEffects.None);
}
//determine mode based on user key pressings
if (((dragDropInfo.AllowedEffects & NSDragOperation.Copy) == NSDragOperation.Copy) && ((dragDropInfo.KeyStates & NSEventModifierMask.AlternateKeyMask) == NSEventModifierMask.AlternateKeyMask))
{
return(DragDropPointerEffects.Copy | DragDropPointerEffects.Track);
}
//if (((dragDropInfo.AllowedEffects & NSDragOperation.Move) == NSDragOperation.Move) && ((dragDropInfo.KeyStates & NSEventModifierMask.ShiftKey) == NSEventModifierMask.ShiftKey))
// return DragDropPointerEffects.Move | DragDropPointerEffects.Track;
//if control flow gets here, then the user's key pressings must be ignored in order to continue the drag/drop operation because
//the combination of the user's key pressings with the allowed drag/drop effects is invalid.
//if move mode is allowed, set move effect
if ((dragDropInfo.AllowedEffects & NSDragOperation.Move) == NSDragOperation.Move)
{
return(DragDropPointerEffects.Move | DragDropPointerEffects.Track);
}
//if copy mode is allowed, then indicate copy mode
if ((dragDropInfo.AllowedEffects & NSDragOperation.Copy) == NSDragOperation.Copy)
{
return(DragDropPointerEffects.Copy | DragDropPointerEffects.Track);
}
return(DragDropPointerEffects.None);
}
/// <summary>
/// Indicates that the drag and drop operation is in progress.
/// </summary>
/// <param name="dragDropInfo">
/// Information about the drag and drop operation in progress.
/// </param>
/// <returns>
/// A <see cref="DragDropPointerEffects"/> for the current operation. For example, this can be used to
/// indicate a copy operation when the CTRL key is down.
/// </returns>
/// <remarks>This method is called continuously while the user is dragging the mouse over the text editor during
/// a drag and drop operation. It can be used to
/// draw additional information next to the mouse cursor as a preview of the text after the drop operation.
/// </remarks>
public virtual DragDropPointerEffects HandleDraggingOver(DragDropInfo dragDropInfo)
{
return(this.GetDragDropEffect(dragDropInfo));
}
/// <summary>
/// This method selects the text at the end of the drop operation.
/// </summary>
/// <remarks>
/// This method will only be called if the drop of data resulted in an <see cref="DragDropEffects"/> other than DragDropEffects.None.
/// </remarks>
/// <param name="insertionPoint">The position at which data was inserted.</param>
/// <param name="dataLength">The length of the data inserted in the buffer.</param>
/// <param name="virtualSpaceLength">The length of whitespace inserted in the buffer to fill the gap between the closest buffer position
/// and the position at which data was dropped. This value will be non-zero only if data was dropped into virtual space.</param>
/// <param name="dragDropInfo">The <see cref="DragDropInfo"/> class containing information about the drop.</param>
/// <param name="reverse">True if the existing selection prior to the drop was reversed.</param>
protected virtual void SelectText(SnapshotPoint insertionPoint, int dataLength, DragDropInfo dragDropInfo, bool reverse)
{
if (insertionPoint == null)
{
throw new ArgumentNullException(nameof(insertionPoint));
}
if (dragDropInfo == null)
{
throw new ArgumentNullException(nameof(dragDropInfo));
}
VirtualSnapshotPoint anchorPoint = new VirtualSnapshotPoint(insertionPoint);
VirtualSnapshotPoint activePoint = new VirtualSnapshotPoint(insertionPoint.Add(dataLength));
if (dragDropInfo.IsInternal && reverse)
{
_editorOperations.SelectAndMoveCaret(activePoint, anchorPoint, TextSelectionMode.Stream);
}
else
{
_editorOperations.SelectAndMoveCaret(anchorPoint, activePoint, TextSelectionMode.Stream);
}
}
/// <summary> /// This method is called after the edits are made to the buffer to perform any necessary post edit actions. /// </summary> /// <param name="successfulEdit">If true, the edits performed on the buffer were successful, otherwise, the edits failed.</param> /// <param name="dragDropInfo">The <see cref="DragDropInfo"/> holding information about the currently ongoing drag/drop operation.</param> protected abstract void PerformPostEditActions(DragDropInfo dragDropInfo, bool successfulEdit);
/// <summary> /// This method is called before edits are made to the buffer to perform any necessary pre edit actions. /// </summary> /// <param name="dragDropInfo">The <see cref="DragDropInfo"/> holding information about the currently ongoing drag/drop operation.</param> protected abstract void PerformPreEditActions(DragDropInfo dragDropInfo);
/// <summary> /// This method extracts the text of an <see cref="DragDropInfo"/> object. /// </summary> protected abstract string ExtractText(DragDropInfo dragDropInfo);
/// <summary>
/// Indicates that the drag and drop operation has completed, and that the final tasks, if any, should be performed now.
/// </summary>
/// <param name="dragDropInfo">
/// Information about the drag and drop operation in progress.
/// </param>
/// <returns>
/// The drag and drop effects of this drop operation. For example, if the drop operation has moved data,
/// DragDropPointerEffects.Move should be returned.
/// </returns>
/// <remarks>This method is called when the user drops the data onto the editor.
/// This marks the end of a drag and drop operation.
/// The <see cref="IDropHandler"/> is expected to perform the final tasks of the operation.
/// </remarks>
public virtual DragDropPointerEffects HandleDataDropped(DragDropInfo dragDropInfo)
{
if (dragDropInfo == null)
{
throw new ArgumentNullException(nameof(dragDropInfo));
}
ITextSelection selection = _cocoaTextView.Selection;
//keeps track of the result of this operation
DragDropPointerEffects result = DragDropPointerEffects.None;
//tracks the location at which the data was dropped
VirtualSnapshotPoint dropLocation = dragDropInfo.VirtualBufferPosition;
//convert the drag/drop data to text
string dragDropText = this.ExtractText(dragDropInfo);
bool isReversed = selection.IsReversed;
bool copyRequested = (dragDropInfo.KeyStates & NSEventModifierMask.AlternateKeyMask) == NSEventModifierMask.AlternateKeyMask;
bool copyAllowed = (dragDropInfo.AllowedEffects & NSDragOperation.Copy) == NSDragOperation.Copy;
ITextSnapshot preEditSnapshot = _cocoaTextView.TextSnapshot;
// track the point where the data will be inserted
ITrackingPoint insertionPoint = preEditSnapshot.CreateTrackingPoint(dropLocation.Position, PointTrackingMode.Negative);
// track the currently selected spans before any edits are performed on the buffer
List <ITrackingSpan> selectionSpans = new List <ITrackingSpan>();
foreach (SnapshotSpan selectedSpan in selection.SelectedSpans)
{
selectionSpans.Add(preEditSnapshot.CreateTrackingSpan(selectedSpan, SpanTrackingMode.EdgeExclusive));
}
// perform any necessary pre edit actions
this.PerformPreEditActions(dragDropInfo);
// clear selection before data operations
if (!selection.IsEmpty)
{
selection.Clear();
}
// a reference to the snapshot resulting from the edits
bool successfulEdit = false;
// if the data is being dropped in virtual space, calculate how many whitespace characters will be inserted
// to fill the gap between the dropped point and the closest buffer position
int virtualSpaceLength = 0;
if (dragDropInfo.VirtualBufferPosition.IsInVirtualSpace)
{
virtualSpaceLength = _editorOperations.GetWhitespaceForVirtualSpace(dragDropInfo.VirtualBufferPosition).Length;
}
if (copyRequested && copyAllowed)
{
//copy the data by inserting it in the buffer
successfulEdit = this.InsertText(dropLocation, dragDropText);
if (successfulEdit)
{
result = DragDropPointerEffects.Copy;
}
}
else
{
//the data needs to be moved
if (dragDropInfo.IsInternal)
{
//delete the existing selection, and add the data to the new location
successfulEdit = this.MoveText(dropLocation, selectionSpans, dragDropText);
}
else
{
//the drag is not from this text view, just insert the data at dropLocation
successfulEdit = this.InsertText(dropLocation, dragDropText);
}
//set the pointer effect to move if the edit was successful since that implies that the data was moved successfully
if (successfulEdit)
{
result = DragDropPointerEffects.Move;
}
}
// finally select the newly inserted data if the operation was successful
if (result != DragDropPointerEffects.None)
{
SnapshotPoint textInsertionPoint = insertionPoint.GetPoint(_cocoaTextView.TextSnapshot);
// if the data was inserted in virtual space, offset the selection's anchor point by the whitespace that was inserted
// in virtual space
if (virtualSpaceLength != 0)
{
textInsertionPoint = textInsertionPoint.Add(virtualSpaceLength);
}
this.SelectText(textInsertionPoint, dragDropText.Length, dragDropInfo, isReversed);
}
// perform any post edit actions as necessary
this.PerformPostEditActions(dragDropInfo, successfulEdit);
return(result);
}
