Row Dragging in Web Components Grid

The Ignite UI for Web Components Row Dragging feature in Web Components Grid is easily configurable and is used for rearranging rows within the grid by dragging and dropping them to a new position using the mouse. It is initialized on the root IgcGrid component and is configurable via the IgcGrid.rowDraggable input.

Web Components Grid Row Drag Example

Configuration

In order to enable row-dragging for your IgcGrid, all you need to do is set the grid’s IgcGrid.rowDraggable to true. Once this is enabled, a row-drag handle will be displayed on each row. This handle can be used to initiate row dragging. Clicking on the drag-handle and moving the cursor while holding down the button will cause the grid’s IgcGrid.rowDragStart event to fire. Releasing the click at any time will cause IgcGrid.rowDragEnd event to fire.

<igc-grid row-draggable="true">
</igc-grid>

Drop Areas

First we need to register the DragDropModule:

import { IgcDragDropModule } from 'igniteui-webcomponents';
// ...
ModuleManager.register(
    IgcDragDropModule
);

In this case, our drop-area will be a whole second grid where we’ll drop the rows.

<igc-grid id="targetGrid" auto-generate="false" primary-key="ID">
</igc-grid>

constructor() {
    var targetGrid = this.targetGrid = document.getElementById('targetGrid') as IgcGridComponent;

    this._bind = () => {
        targetGrid.data = this.data;
        targetGrid.emptyGridTemplate = this.dragHereTemplate;
        targetGrid.enter = this.onEnterAllowed;
        targetGrid.leave = this.onLeaveAllowed;
        targetGrid.dropped = this.onDropAllowed;
    }
    this._bind();
}

public dragHereTemplate = (ctx: IgcGridEmptyTemplateContext) => {
    return html`Drop a row to add it to the grid`;
}

export class IgcGridRowDragComponent {
    constructor() {
        var sourceGrid = this.sourceGrid = document.getElementById('sourceGrid') as IgcGridComponent;
        var targetGrid = this.targetGrid = document.getElementById('targetGrid') as IgcGridComponent;
    }

    public onDropAllowed(args) {
        this.targetGrid.addRow(args.dragData.data);
        this.sourceGrid.deleteRow(args.dragData.key);
    }
}

constructor() {
    var grid = this.grid = document.getElementById('grid') as IgcGridComponent;

    this._bind = () => {
        grid.rowDragGhost = this.rowDragGhostTemplate;
    }
    this._bind();
}

public rowDragGhostTemplate = (ctx: IgcGridRowDragGhostContext) => {
    return html`<igc-icon fontSet="material">arrow_right_alt</igc-icon>`;
}

Templating the Drag Icon

The drag handle icon can be templated using the grid’s DragIndicatorIconTemplate. In the example we’re building, let’s change the icon from the default one (drag_indicator) to drag_handle.

Once our drop handlers are properly configured, we’re good to go!

The result of the configuration can be seem below:

Example Demo

Application Demo

Row Reordering Demo

With the help of the grid’s row drag events you can create a grid that allows you to reorder rows by dragging them.

<igc-grid id="grid" row-draggable="true" primary-key="ID">
</igc-grid>

constructor() {
    var grid = this.grid = document.getElementById('grid') as IgcGridComponent;
    grid.addEventListener("rowDragEnd", this.webGridReorderRowHandler)
}

Once IgcGrid.rowDraggable is enabled and a drop zone has been defined, you need to implement a simple handler for the drop event. When a row is dragged, check the following:

• Was the row dropped inside of the grid?
• If so, on which other row was the dragged row dropped?
• Once you’ve found the target row, swap the records’ places in the Data array

Below, you can see this implemented:

public webGridReorderRowHandler(args: CustomEvent<IgcRowDragEndEventArgs>): void {
    const ghostElement = args.detail.dragDirective.ghostElement;
    const dragElementPos = ghostElement.getBoundingClientRect();
    const grid = document.getElementsByTagName["igc-grid"](0) as any;
    const rows = Array.prototype.slice.call(document.getElementsByTagName("igx-grid-row"));
    const currRowIndex = this.getCurrentRowIndex(rows,
    { x: dragElementPos.x, y: dragElementPos.y });
    if (currRowIndex === -1) { return; }
    // remove the row that was dragged and place it onto its new location
    grid.deleteRow(args.detail.dragData.key);
    grid.data.splice(currRowIndex, 0, args.detail.dragData.data);
}

public getCurrentRowIndex(rowList: any[], cursorPosition) {
    for (const row of rowList) {
        const rowRect = row.getBoundingClientRect();
        if (cursorPosition.y > rowRect.top + window.scrollY && cursorPosition.y < rowRect.bottom + window.scrollY &&
            cursorPosition.x > rowRect.left + window.scrollX && cursorPosition.x < rowRect.right + window.scrollX) {
            // return the index of the targeted row
            return parseInt(row.attributes["data-rowindex"].value);
        }
    }
    return -1;
}

With these few easy steps, you’ve configured a grid that allows reordering rows via drag/drop! You can see the above code in action in the following demo.

Holding onto the drag icon will allow you to move a row anywhere in the grid:

Limitations

Currently, there are no known limitations for the IgcGrid.rowDraggable.

API References

Additional Resources

Our community is active and always welcoming to new ideas.

• Ignite UI for Web Components Forums
• Ignite UI for Web Components GitHub