public class GridItemsDroppedEventArgs :
    GridItemsDroppedEventArgsBase

<DxGrid @ref="Grid"
        Data="DataSource"
        AllowDragRows="true"
        ItemsDropped="Grid_ItemsDropped"
        CssClass="max-h-480">
    <Columns>
        <DxGridDataColumn FieldName="Name" Caption="Subject" MinWidth="220" />
        <DxGridDataColumn FieldName="Status" Caption="Status" Width="140px" MinWidth="140" />
        <DxGridDataColumn FieldName="CreatedDate" Caption="Created" Width="120px" MinWidth="120" />
        <DxGridDataColumn FieldName="FixedDate" Caption="Fixed" Width="120px" MinWidth="120" />
    </Columns>
</DxGrid>

@code {
    IGrid Grid;
    ObservableCollection<Issue> DataSource { get; set; }
    protected override async Task OnInitializedAsync() {
        DataSource = new ObservableCollection<Issue>(await IssuesDataService.GetIssuesAsync());
    }
    void Grid_ItemsDropped(GridItemsDroppedEventArgs evt) {
        var droppedItem = (Issue)evt.DroppedItems[0];
        DataSource.Remove(droppedItem);
        var targetItem = (Issue)evt.TargetItem;
        var index = targetItem != null
            ? DataSource.IndexOf(targetItem) + (evt.DropPosition == GridItemDropPosition.After ? 1 : 0)
            : DataSource.Count;
        DataSource.Insert(index, droppedItem);
    }
}

<DxGrid @ref="@InStockGrid"
        Data="InStockProducts"
        AllowDragRows="true"
        AllowedDropTarget="GridAllowedDropTarget.External">
    <Columns>
        <DxGridDataColumn FieldName="ProductName" MinWidth="50" />
        <DxGridDataColumn FieldName="UnitPrice" DisplayFormat="c2" />
    </Columns>
</DxGrid>

<DxGrid Data="DiscontinuedProducts"
        AllowDragRows="true"
        AllowedDropTarget="GridAllowedDropTarget.All"
        ItemsDropped="Grid_ItemsDropped">
    <Columns>
        <DxGridDataColumn FieldName="ProductName" MinWidth="50" />
        <DxGridDataColumn FieldName="UnitPrice" DisplayFormat="c2" />
    </Columns>
</DxGrid>

@code {
    IGrid InStockGrid { get; set; }

    ObservableCollection<Product> InStockProducts { get; set; }
    ObservableCollection<Product> DiscontinuedProducts { get; set; }

    protected override async Task OnInitializedAsync() {
        var products = await NwindDataService.GetProductsAsync();
        InStockProducts = new ObservableCollection<Product>(products.Where(p => p.InStock));
        DiscontinuedProducts = new ObservableCollection<Product>(products.Where(p => p.Discontinued));
    }

    void Grid_ItemsDropped(GridItemsDroppedEventArgs evt) {
        var sourceProducts = GetProductCollection(evt.SourceComponent);
        RemoveDroppedItems(sourceProducts, evt.DroppedItems);

        var destinationProducts = GetProductCollection(evt.Grid);
        var targetProduct = (Product)evt.TargetItem;
        var index = targetProduct != null
            ? destinationProducts.IndexOf(targetProduct) + (evt.DropPosition == GridItemDropPosition.After ? 1 : 0)
            : destinationProducts.Count;

        InsertDroppedItems(destinationProducts, evt.DroppedItems, index);
    }

    ObservableCollection<Product> GetProductCollection(object grid) {
        return grid == InStockGrid ? InStockProducts : DiscontinuedProducts;
    }

    void RemoveDroppedItems(IList<Product> sourceProducts, IEnumerable<object> droppedItems) {
        foreach(var item in droppedItems)
            sourceProducts.Remove((Product)item);
    }

    void InsertDroppedItems(IList<Product> destinationProducts, IEnumerable<object> droppedItems, int index) {
        foreach(var item in droppedItems.Reverse())
            destinationProducts.Insert(index, (Product)item);
    }
}