Merged PR 21140: update info about drag-drop ops

update info about drag-drop ops

Author: jwmsft

windows.ui.xaml/drageventargs_acceptedoperation.md

@@ -10,17 +10,33 @@ public Windows.ApplicationModel.DataTransfer.DataPackageOperation AcceptedOperat
 # Windows.UI.Xaml.DragEventArgs.AcceptedOperation
 
 ## -description
-Gets or sets a value that specifies which operations are allowed by the originator of the drag event.
-
 
+Gets or sets a value that specifies which operations (none, move, copy, and/or link) can be accepted by the target of the drag event.
 
 ## -property-value
-A member of the [DataPackageOperation](../windows.applicationmodel.datatransfer/datapackageoperation.md) enumeration that specifies which operations are allowed by the originator of the drag event.
+
+A value or bitwise combination of values that specifies which operations can be accepted by the target of the drag event.
 
 ## -remarks
 
+This value is set in the [DragEnter](uielement_dragenter.md) or [DragOver](uielement_dragover.md) event of the `UIElement` that is a potential drop target of the drag and drop operation. It notifies the drag source of what operations it can accept, if any, for the [DataPackage](../windows.applicationmodel.datatransfer/datapackage.md) that is being dragged.
+
+For more info about data operations, see the [DataPackageOperation](../windows.applicationmodel.datatransfer/datapackageoperation.md) enumeration.
+
 ## -examples
 
+In this example, a `ListView` accepts only text content. In the `DragOver` event handler, the `AcceptedOperation` is set to `Copy` if the `DataPackage` contains text; otherwise, `AcceptedOperation` is set to `None`.
+
+```csharp
+private void TargetListView_DragOver(object sender, DragEventArgs e)
+{
+    // The list accepts only text.
+    e.AcceptedOperation = 
+       (e.DataView.Contains(StandardDataFormats.Text)) 
+           ? DataPackageOperation.Copy : DataPackageOperation.None;
+}
+```
+
 ## -see-also
 
 [Drag-and-drop overview](/windows/uwp/design/input/drag-and-drop)

windows.ui.xaml/drageventargs_allowedoperations.md

@@ -10,19 +10,21 @@ public Windows.ApplicationModel.DataTransfer.DataPackageOperation AllowedOperati
 # Windows.UI.Xaml.DragEventArgs.AllowedOperations
 
 ## -description
-Gets the allowed data package operations (none, move, copy, and/or link) for the drag and drop operation.
-
 
+Gets a value that specifies which operations (none, move, copy, and/or link) are allowed by the source of the drag event.
 
 ## -property-value
-The allowed data operations.
+
+A value or bitwise combination of values that specifies which operations are allowed by the source of the drag event.
 
 ## -remarks
-For more info about the allowed data operations, see [DataPackageOperation](../windows.applicationmodel.datatransfer/datapackageoperation.md).
 
-This value is set in the [DragStarting](uielement_dragstarting.md) event handler. See the DragStartingEventArgs.AllowedOperations property.
+This value is set in the [UIElement.DragStarting](uielement_dragstarting.md) event handler via the [DragStartingEventArgs.AllowedOperations](dragstartingeventargs_allowedoperations.md) property. It can then be read from this property in the [DragEnter](uielement_dragenter.md) and [DragOver](uielement_dragover.md) events of the `UIElement` that is a potential drop target of the drag and drop operation. It notifies the target which data package operations (none, move, copy, and/or link) are allowed by the source.
+
+For more info about the allowed data operations, see the [DataPackageOperation](../windows.applicationmodel.datatransfer/datapackageoperation.md) enumeration.
 
 ## -examples
 
 ## -see-also
+
 [Drag-and-drop overview](/windows/uwp/design/input/drag-and-drop), [DragStarting](uielement_dragstarting.md), DragStartingEventArgs.AllowedOperations, [CoreDragOperation.AllowedOperations](../windows.applicationmodel.datatransfer.dragdrop.core/coredragoperation_allowedoperations.md)

windows.ui.xaml/dragstartingeventargs_allowedoperations.md

@@ -10,15 +10,18 @@ public Windows.ApplicationModel.DataTransfer.DataPackageOperation AllowedOperati
 # Windows.UI.Xaml.DragStartingEventArgs.AllowedOperations
 
 ## -description
-Gets or sets the allowed data package operations (none, move, copy, and/or link) for the drag and drop operation.
-
 
+Gets or sets a value that specifies which operations (none, move, copy, and/or link) are allowed by the source of the drag event.
 
 ## -property-value
-The allowed data operations.
+
+A value or bitwise combination of values that specifies which operations are allowed by the source of the drag event.
 
 ## -remarks
-For more info about the allowed data operations, see [DataPackageOperation](../windows.applicationmodel.datatransfer/datapackageoperation.md).
+
+This value is set in the [UIElement.DragStarting](uielement_dragstarting.md) event handler. It can then be read from the [DragEventArgs.AllowedOperations](drageventargs_allowedoperations.md) property in the [DragEnter](uielement_dragenter.md) and [DragOver](uielement_dragover.md) events of the `UIElement` that is a potential drop target of the drag and drop operation. It notifies the target which data package operations (none, move, copy, and/or link) are allowed by the source.
+
+For more info about the allowed data operations, see the [DataPackageOperation](../windows.applicationmodel.datatransfer/datapackageoperation.md) enumeration.
 
 ## -examples