How to drag and drop rows in NSTableView in Mac - xamarin

Question

I have struck with one point i.e now I have got a list of data using NSTableView but what my requirement is, able to drag and drop that rows from one row position to another row position. please give any suggestion for get out this problem. Thanks in advance.
My sample code

Answer 1

Within your NSTableViewDataSource subclass implement WriteRows, ValidateDrop and AcceptDrop and register which Drag/Drop targets your NSTableView accepts. In this case you are only accepting Drops from within your own NSTableView.
Assign a name that will be used for valid drag operations on this NSTableView:
// Any name can be registered, I find using the class name
// of the items in the datasource is cleaner than a const string
string DragDropType = typeof(Product).FullName;
Register the drag types for your NSTableView:
ProductTable.RegisterForDraggedTypes(new string[] { DragDropType });
Implement drag/drop methods on your NSTableViewDataSource:
public override bool WriteRows(NSTableView tableView, NSIndexSet rowIndexes, NSPasteboard pboard)
{
var data = NSKeyedArchiver.ArchivedDataWithRootObject(rowIndexes);
pboard.DeclareTypes(new string[] { DragDropType }, this);
pboard.SetDataForType(data, DragDropType);
return true;
}
public override NSDragOperation ValidateDrop(NSTableView tableView, NSDraggingInfo info, nint row, NSTableViewDropOperation dropOperation)
{
tableView.SetDropRowDropOperation(row, dropOperation);
return NSDragOperation.Move;
}
public override bool AcceptDrop(NSTableView tableView, NSDraggingInfo info, nint row, NSTableViewDropOperation dropOperation)
{
var rowData = info.DraggingPasteboard.GetDataForType(DragDropType);
if (rowData == null)
return false;
var dataArray = NSKeyedUnarchiver.UnarchiveObject(rowData) as NSIndexSet;
Console.WriteLine($"{dataArray}");
// Move hack for this example... you need to handle the complete NSIndexSet
tableView.BeginUpdates();
var tmpProduct = Products[(int)dataArray.FirstIndex];
Products.RemoveAt((int)dataArray.FirstIndex);
if (Products.Count == row - 1)
Products.Insert((int)row - 1 , tmpProduct);
else
Products.Insert((int)row, tmpProduct);
tableView.ReloadData();
tableView.EndUpdates();
return true;
}