UWP Gridview 固定项目位置

Question

In my UWP app, I have this gridview with items reordering enabled

        <GridView Name="ModulesGridView" CanReorderItems="True" ItemsSource="{x:Bind DataSource, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"
 IsItemClickEnabled="False"  IsHoldingEnabled="False" IsTapEnabled="False" AllowDrop="True" Drop="Drop_Module"
 DragOver="Grid_DragOver" ItemTemplateSelector="{StaticResource MyDataTemplateSelector}">           
        </GridView>

and I want to have an item in this gridview to be always at the end, no matter how I will reorder the items. It will be always at the end. Is there any way to achieve this?

Answer 1

GridView does not have a native API to support this feature, but we can achieve the goal in other ways.

For simplicity, we assume that your DataSource is of type ObservableCollection<int> . If your actual type is more complex than int, you need to override the EqualTo method for this class in advance.

1. Allow CanDragItems and add corresponding events

<GridView ...
          CanDragItems="True"
          DragItemsCompleted="ModulesGridView_DragItemsCompleted">
</GridView>

2. Extract the last item in advance when loading the data collection

private int LastItem = 0;

...

for (int i = 0; i < 20; i++)
{
    DataSource.Add(i);
}
LastItem = DataSource.Last();

3. Check the position of the last item in the DragItemsCompleted event

private void ModulesGridView_DragItemsCompleted(ListViewBase sender, DragItemsCompletedEventArgs args)
{
    int index = DataSource.IndexOf(LastItem);
    if (index != DataSource.Count - 1)
    {
        DataSource.Move(index, DataSource.Count - 1);
    }
}

In other words, we do not interfere with the process of reordering items by the user, but after reordering, we detect the position of the last item. If it is not at the end, we move it again.

Thanks.