DxGrid.AllowedDropTarget Property

Namespace: DevExpress.Blazor

Assembly: DevExpress.Blazor.v25.1.dll

NuGet Package: DevExpress.Blazor

Declaration

[DefaultValue(GridAllowedDropTarget.Internal)]
[Parameter]
public GridAllowedDropTarget AllowedDropTarget { get; set; }

Property Value

Remarks

Activate the AllowDragRows option to render drag handles for data rows. The AllowedDropTarget property specifies whether these handles allow users to reorder rows or drop them from this Grid to other components. Handle the target component’s ItemsDropped event to update the data source accordingly.

View Example: Implement Row Drag and Drop Functionality

In the following example, the first Grid allows users to drag rows to external targets. The second Grid accepts rows from the first Grid and allows row reordering:

Run Demo: Drag and Drop Rows - Between Components

<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);
    }
}