Add support for printing GCode

- Issue MatterHackers/MatterControl#3457
MC2 2.0.0.9727 Gcode files do not print
- Enable print from current bed plate
- Enable print from library selection

ApplicationView/PrinterModels.cs

@@ -189,6 +189,28 @@ namespace MatterHackers.MatterControl
 			return insertionGroup;
 		}
 
+		public async Task StashAndPrintGCode(ILibraryItem libraryItem)
+		{
+			// Clear plate
+			await this.ClearPlate();
+
+			// Add content
+			await this.LoadContent(
+				new EditContext()
+				{
+					SourceItem = libraryItem,
+					// No content store for GCode, otherwise PlatingHistory
+					ContentStore = this.EditContext.ContentStore
+				});
+
+			// Slice and print
+			await ApplicationController.Instance.PrintPart(
+				this.EditContext,
+				this.Printer,
+				null,
+				CancellationToken.None);
+		}
+
 		public async Task StashAndPrint(IEnumerable<ILibraryItem> selectedLibraryItems)
 		{
 			// Clear plate

Library/Widgets/PrintLibraryWidget.cs

@@ -525,7 +525,14 @@ namespace MatterHackers.MatterControl.PrintLibrary
 							printer.Connection.StartSdCardPrint(sdcardItem.Name.ToLower());
 							break;
 						case FileSystemFileItem fileItem when Path.GetExtension(fileItem.FileName).ToUpper() == ".GCODE":
-							//ApplicationController.Instance.ActivePrintItem = new PrintItemWrapper(new PrintItem(fileItem.Name, fileItem.Path));
+							if (printer != null)
+							{
+								UiThread.RunOnIdle(async () =>
+								{
+									await printer.Bed.StashAndPrintGCode(fileItem);
+								});
+							}
+
 							break;
 						default:
 							//TODO: Otherwise add the selected items to the plate and print the plate?
@@ -559,9 +566,26 @@ namespace MatterHackers.MatterControl.PrintLibrary
 				Title = "Add to Plate".Localize(),
 				Action = (selectedLibraryItems, listView) =>
 				{
-					// TODO: Sort out the right way to have an ActivePrinter context that looks and behaves correctly
 					var activeContext = ApplicationController.Instance.DragDropData;
-					activeContext.SceneContext.AddToPlate(selectedLibraryItems);
+					var printer = activeContext.Printer;
+
+					if (listView.SelectedItems.Count == 1 &&
+						selectedLibraryItems.FirstOrDefault() is ILibraryAssetStream assetStream
+						&& assetStream.ContentType == "gcode")
+					{
+						// Drop handler for special case of GCode or similar (change loaded scene to new context)
+						printer.Bed.LoadContent(
+							new EditContext()
+							{
+								SourceItem = assetStream,
+								// No content store for GCode, otherwise PlatingHistory
+								ContentStore = printer.Bed.EditContext.ContentStore
+							}).ConfigureAwait(false);
+					}
+					else
+					{
+						activeContext.SceneContext.AddToPlate(selectedLibraryItems);
+					}
 				},
 				IsEnabled = (selectedListItems, listView) =>
 				{

PartPreviewWindow/View3D/PrinterBar/PrintPopupMenu.cs

@@ -35,6 +35,7 @@ using MatterHackers.Agg;
 using MatterHackers.Agg.UI;
 using MatterHackers.Localizations;
 using MatterHackers.MatterControl.CustomWidgets;
+using MatterHackers.MatterControl.Library;
 using MatterHackers.MatterControl.SlicerConfiguration;
 using MatterHackers.VectorMath;
 
@@ -145,7 +146,9 @@ namespace MatterHackers.MatterControl.PartPreviewWindow
 				};
 				button.Click += (s, e) =>
 				{
-					if (!printer.Bed.Scene.Children.Any())
+					// Exit if the bed is not GCode and the bed has no items
+					if ((printer.Bed.EditContext.SourceItem as ILibraryAsset)?.ContentType != "gcode"
+						&& printer.Bed.Scene.Children.Count <= 0)
 					{
 						return;
 					}