DxDataGrid<T>.RowInsertingAsync Event

Occurs when a user adds a new data row and allows you to await handler execution without blocking the Data Grid.

Namespace: DevExpress.Blazor

Assembly: DevExpress.Blazor.v22.1.dll

Declaration

[Parameter]
public Func<IDictionary<string, object>, Task> RowInsertingAsync { get; set; }

Parameters

Type	Description
IDictionary<String, Object>	A dictionary that lists column names and column values.

Remarks

Important

The Data Grid was moved to maintenance support mode. No new features/capabilities will be added to this component. We recommend that you migrate to the Grid component.

When users click the New button in a command column, the grid displays the Edit Form where you can specify a new row’s data. To post new values to the Data Grid’s data source or discard these values, handle the RowInsertingAsync event.

To control the visibility of the New button, use the NewButtonVisible property.

Razor

@inject MyApp.Data.WeatherForecastService ForecastService
@using MyApp.Data

<DxDataGrid DataAsync="@ForecastService.GetForecastAsync" 
            RowInsertingAsync="@OnRowInserting"
            InitNewRow="@OnInitNewRow">
    <DxDataGridCommandColumn />
    <DxDataGridDateEditColumn Field=@nameof(WeatherForecast.Date) />
    <DxDataGridSpinEditColumn Field="@nameof(WeatherForecast.TemperatureC)" 
                              Caption="@("Temp. (\x2103)")" />
    <DxDataGridColumn Field=@nameof(WeatherForecast.TemperatureF) Caption="Temp. (F)" />
</DxDataGrid>

@code {
    async Task OnRowInserting(IDictionary<string, object> newValue) {
        await ForecastService.Insert(newValue);
    }

    Task OnInitNewRow(Dictionary<string, object> values) {
        values.Add("Date", DateTime.Now);
        values.Add("TemperatureC", 13);
        return Task.CompletedTask;
    }
}

WeatherForecast

using System;

namespace MyApp.Data {
    public class WeatherForecast {
        public DateTime Date { get; set; }
        public int TemperatureC { get; set; }
        public int TemperatureF => 32 + (int)(TemperatureC / 0.5556);
    }
}

WeatherForecastService

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;

namespace MyApp.Data {
    public class WeatherForecastService {

        private List<WeatherForecast> CreateForecast() {
            var rng = new Random();
            DateTime startDate = DateTime.Now;

            return Enumerable.Range(1, 15).Select(index => new WeatherForecast {
                Date = startDate.AddDays(index),
                TemperatureC = rng.Next(-15, 20)
            }).ToList();
        }

        private List<WeatherForecast> Forecasts { get; set; }

        public WeatherForecastService() {
            Forecasts = CreateForecast();
        }

        public Task<IEnumerable<WeatherForecast>> GetForecastAsync(CancellationToken ct = default) {
            return Task.FromResult(Forecasts.AsEnumerable());
        }

        WeatherForecast[] UpdateInternal(WeatherForecast dataItem, IDictionary<string, object> newValue) {
            foreach (var field in newValue.Keys) {
                switch (field) {
                    case nameof(dataItem.Date):
                        dataItem.Date = (DateTime)newValue[field];
                        break;
                    case nameof(dataItem.TemperatureC):
                        dataItem.TemperatureC = (int)newValue[field];
                        break;
                }
            }
            return Forecasts.ToArray();
        }

        public Task<WeatherForecast[]> Update(WeatherForecast dataItem, IDictionary<string, object> newValue) {
            return Task.FromResult(UpdateInternal(dataItem, newValue));
        }

        WeatherForecast[] InsertInternal(IDictionary<string, object> newValue) {
            var dataItem = new WeatherForecast();
            Update(dataItem, newValue);
            Forecasts.Insert(0, dataItem);
            return Forecasts.ToArray();
        }

        public Task<WeatherForecast[]> Insert(IDictionary<string, object> newValue) {
            return Task.FromResult(InsertInternal(newValue));
        }
    }
}

Program.cs

// ...
builder.Services.AddSingleton<WeatherForecastService>();

Note

If you bind the data grid to a data source that does not implement the INotifyCollectionChanged interface, you should reload data and redraw the grid after a row is inserted. To do this, use the Refresh method in the OnRowInserting handler.