|
| 1 | +--- |
| 2 | +title: Drag and Drop Items between Grids in Different Components |
| 3 | +description: Learn how to drag and drop data items between Telerik Blazor Grids, TreeLists, or TreeViews which are nested inside different parent components. |
| 4 | +type: how-to |
| 5 | +page_title: How to Drag and Drop Items between Grids in Different Parent Components |
| 6 | +slug: grid-kb-drag-drop-in-different-components |
| 7 | +tags: telerik, blazor, grid, treelist, treeview, drag and drop |
| 8 | +ticketid: |
| 9 | +res_type: kb |
| 10 | +--- |
| 11 | + |
| 12 | +## Environment |
| 13 | + |
| 14 | +<table> |
| 15 | + <tbody> |
| 16 | + <tr> |
| 17 | + <td>Product</td> |
| 18 | + <td> |
| 19 | + Grid for Blazor, <br /> |
| 20 | + TreeList for Blazor, <br /> |
| 21 | + TreeView for Blazor |
| 22 | + </td> |
| 23 | + </tr> |
| 24 | + </tbody> |
| 25 | +</table> |
| 26 | + |
| 27 | +## Description |
| 28 | + |
| 29 | +This KB shows how to implement drag and drop between two Telerik components, which are inside different parent Razor components. |
| 30 | + |
| 31 | +## Solution |
| 32 | + |
| 33 | +You can approach drag and drop across different parent components in at least two ways: |
| 34 | + |
| 35 | +* Use parameters and `EventCallback`s to pass information between the two parent Razor components, which hold the Telerik components. This is a suitable approach if the two parent components are siblings in their parent. |
| 36 | +* Use a state management service in your app, which will execute methods and fire events to the Razor components that hold the Telerik components. This is a suitable approach in all cases, but especially if the two parent components are further away in the app component hierarchy. |
| 37 | + |
| 38 | +The described algorithm and the example below are applicable for the [Grid]({%slug grid-drag-drop-overview%}), [TreeList]({%slug treelist-drag-drop-overview%}), and [TreeView]({%slug treeview-drag-drop-overview%}). |
| 39 | + |
| 40 | +## Example |
| 41 | + |
| 42 | +The following example includes three files: |
| 43 | + |
| 44 | +* `GridContainer.razor` is a Razor component that contains a Grid with enabled row drag and drop. |
| 45 | +* `Home.razor` is a component (page) that holds two `GridContainer` instances. |
| 46 | +* `GridModel.cs` is the Grid model class. |
| 47 | + |
| 48 | +Adjust the `YourAppName` namespace in `Home.razor` and `GridModel.cs` to run the code successfully in your app. |
| 49 | + |
| 50 | +<div class="skip-repl"></div> |
| 51 | + |
| 52 | +````Home.razor |
| 53 | +@page "/" |
| 54 | +
|
| 55 | +@using YourAppName.Data |
| 56 | +
|
| 57 | +<h2>Grid 1</h2> |
| 58 | +<GridContainer OnItemsDropped="@OnGridItemsDropped" |
| 59 | + @bind-GridData="@Grid1Data" |
| 60 | + @bind-GridRef="@Grid1Ref" /> |
| 61 | +
|
| 62 | +<h2>Grid 2</h2> |
| 63 | +<GridContainer OnItemsDropped="@OnGridItemsDropped" |
| 64 | + @bind-GridData="@Grid2Data" |
| 65 | + @bind-GridRef="@Grid2Ref" /> |
| 66 | +
|
| 67 | +@code { |
| 68 | + private TelerikGrid<GridModel>? Grid1Ref { get; set; } |
| 69 | +
|
| 70 | + private TelerikGrid<GridModel>? Grid2Ref { get; set; } |
| 71 | +
|
| 72 | + private List<GridModel> Grid1Data { get; set; } = Enumerable.Range(1, 5).Select(x => new GridModel |
| 73 | + { |
| 74 | + Id = x, |
| 75 | + Name = $"Name {x}" |
| 76 | + }).ToList(); |
| 77 | +
|
| 78 | + private List<GridModel> Grid2Data { get; set; } = Enumerable.Range(6, 5).Select(x => new GridModel |
| 79 | + { |
| 80 | + Id = x, |
| 81 | + Name = $"Name {x}" |
| 82 | + }).ToList(); |
| 83 | +
|
| 84 | + private void OnGridItemsDropped(GridRowDropEventArgs<GridModel> args) |
| 85 | + { |
| 86 | + var destinationData = args.DestinationGrid == Grid1Ref ? Grid1Data : Grid2Data; |
| 87 | + var destinationIndex = 0; |
| 88 | +
|
| 89 | + if (args.DestinationItem != null) |
| 90 | + { |
| 91 | + destinationIndex = destinationData.IndexOf(args.DestinationItem); |
| 92 | +
|
| 93 | + if (args.DropPosition == GridRowDropPosition.After) |
| 94 | + { |
| 95 | + destinationIndex += 1; |
| 96 | + } |
| 97 | + } |
| 98 | +
|
| 99 | + destinationData.InsertRange(destinationIndex, args.Items); |
| 100 | + } |
| 101 | +} |
| 102 | +```` |
| 103 | +````GridContainer.razor |
| 104 | +@using YourAppName.Data |
| 105 | +
|
| 106 | +<TelerikGrid @ref="@GridRef" |
| 107 | + Data="@GridData" |
| 108 | + TItem="@GridModel" |
| 109 | + RowDraggable="true" |
| 110 | + OnRowDrop="@((GridRowDropEventArgs<GridModel> args) => OnGridRowDrop(args))" |
| 111 | + SelectionMode="@GridSelectionMode.Multiple" |
| 112 | + @bind-SelectedItems="@GridSelectedItems" |
| 113 | + Height="300px"> |
| 114 | + <GridSettings> |
| 115 | + <GridRowDraggableSettings DragClueField="@nameof(GridModel.Name)"></GridRowDraggableSettings> |
| 116 | + </GridSettings> |
| 117 | + <GridColumns> |
| 118 | + <GridCheckboxColumn SelectAll="true" /> |
| 119 | + <GridColumn Field="@(nameof(GridModel.Id))" Width="120px" /> |
| 120 | + <GridColumn Field="@(nameof(GridModel.Name))" Groupable="false" /> |
| 121 | + </GridColumns> |
| 122 | +</TelerikGrid> |
| 123 | +
|
| 124 | +@code { |
| 125 | + [Parameter] |
| 126 | + public EventCallback<GridRowDropEventArgs<GridModel>> OnItemsDropped { get; set; } |
| 127 | +
|
| 128 | + [Parameter] |
| 129 | + public List<GridModel> GridData { get; set; } = new(); |
| 130 | +
|
| 131 | + [Parameter] |
| 132 | + public EventCallback<List<GridModel>> GridDataChanged { get; set; } |
| 133 | +
|
| 134 | + [Parameter] |
| 135 | + public TelerikGrid<GridModel>? GridRef { get; set; } |
| 136 | +
|
| 137 | + [Parameter] |
| 138 | + public EventCallback<TelerikGrid<GridModel>> GridRefChanged { get; set; } |
| 139 | +
|
| 140 | + private IEnumerable<GridModel> GridSelectedItems { get; set; } = new List<GridModel>(); |
| 141 | +
|
| 142 | + private async Task OnGridRowDrop(GridRowDropEventArgs<GridModel> args) |
| 143 | + { |
| 144 | + // Remove items from the source Grid |
| 145 | + GridData.RemoveAll(x => args.Items.Contains(x)); |
| 146 | + await GridDataChanged.InvokeAsync(GridData); |
| 147 | +
|
| 148 | + if (OnItemsDropped.HasDelegate) |
| 149 | + { |
| 150 | + // Add items to the destination Grid |
| 151 | + await OnItemsDropped.InvokeAsync(args); |
| 152 | + } |
| 153 | + } |
| 154 | +
|
| 155 | + protected override async Task OnAfterRenderAsync(bool firstRender) |
| 156 | + { |
| 157 | + if (firstRender && GridRefChanged.HasDelegate) |
| 158 | + { |
| 159 | + // Pass the Grid component references to the parent component |
| 160 | + await GridRefChanged.InvokeAsync(GridRef); |
| 161 | + } |
| 162 | +
|
| 163 | + await base.OnAfterRenderAsync(firstRender); |
| 164 | + } |
| 165 | +} |
| 166 | +```` |
| 167 | +````GridModel.cs |
| 168 | +namespace YourAppName.Data |
| 169 | +{ |
| 170 | + public class GridModel |
| 171 | + { |
| 172 | + public int Id { get; set; } |
| 173 | + |
| 174 | + public string Name { get; set; } = string.Empty; |
| 175 | + } |
| 176 | +} |
| 177 | +```` |
| 178 | + |
| 179 | +## See Also |
| 180 | + |
| 181 | +* [Grid Drag and Drop Documentation]({%slug grid-drag-drop-overview%}) |
| 182 | +* [TreeList Drag and Drop Documentation]({%slug treelist-drag-drop-overview%}) |
| 183 | +* [TreeView Drag and Drop Documentation]({%slug treeview-drag-drop-overview%}) |
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