DxGrid.EditStart Event

Fires before the edit form or row appears.

Namespace: DevExpress.Blazor

Assembly: DevExpress.Blazor.v23.1.dll

NuGet Package: DevExpress.Blazor

Declaration

[Parameter]
public EventCallback<GridEditStartEventArgs> EditStart { get; set; }

Parameters

Type	Description
GridEditStartEventArgs	A GridEditStartEventArgs object that contains data for this event.

Remarks

Users can employ an inline edit row or invoke a standard or pop-up edit form to edit data in the Grid. The EditMode property specifies the current edit mode.

Tip

For information on how to enable data editing, refer to the following topic: Edit Data in Blazor Grid.

The EditStart event occurs in the following cases:

• When a user clicks the New or Edit button in the command column.
• When the StartEditRowAsync, StartEditDataItemAsync, or StartEditNewRowAsync method is called.

Handle this event to create a custom response to the edit start action. Use the IsNew event argument to identify whether the edit form or row is used for a new or existing row. The DataItem property returns the processed data item. You can also access the Grid object and use its members to obtain additional information about the Grid.

You can also set the Cancel property to true to prevent the edit form/row from being shown.

The following example demonstrates how to prevent users from editing unselected rows:

Razor

@using Microsoft.EntityFrameworkCore
@inject IDbContextFactory<NorthwindContext> NorthwindContextFactory
@implements IDisposable

<DxGrid Data="GridDataSource"
        EditModelSaving="OnEditModelSaving"
        KeyFieldName="EmployeeId"
        AllowSelectRowByClick="true"
        SelectionMode="GridSelectionMode.Single"
        @bind-SelectedDataItem="@SelectedDataItem"
        EditStart="OnEditStart"
        EditMode="GridEditMode.EditRow">
    <Columns>
        <DxGridCommandColumn DeleteButtonVisible="false" />
        <DxGridDataColumn FieldName="FirstName" />
        <DxGridDataColumn FieldName="LastName" />
        <DxGridDataColumn FieldName="Title" />
        <DxGridDataColumn FieldName="HireDate" />
    </Columns>
</DxGrid>

@code {
    IEnumerable<object> GridDataSource { get; set; }
    NorthwindContext Northwind { get; set; }
    object SelectedDataItem { get; set; }

    protected override async Task OnInitializedAsync() {
        Northwind = NorthwindContextFactory.CreateDbContext();
        GridDataSource = await Northwind.Employees.ToListAsync();
        SelectedDataItem = GridDataSource.FirstOrDefault();
    }

    async Task OnEditModelSaving(GridEditModelSavingEventArgs e) {
        var editModel = (Employee)e.EditModel;
        var dataItem = e.IsNew ? new Employee() : Northwind.Employees.Find(editModel.EmployeeId);
        if (dataItem != null) {
            dataItem.FirstName = editModel.FirstName;
            dataItem.LastName = editModel.LastName;
            dataItem.Title = editModel.Title;
            dataItem.HireDate = editModel.HireDate;
            if (e.IsNew)
                await Northwind.AddAsync(dataItem);
            await Northwind.SaveChangesAsync();
            GridDataSource = await Northwind.Employees.ToListAsync();
        }
    }

    async Task OnEditStart(GridEditStartEventArgs e) {
        if (!e.IsNew && !e.Grid.IsDataItemSelected(e.DataItem))
            e.Cancel = true;
    }

    public void Dispose() {
        Northwind?.Dispose();
    }
}

Employee

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;

namespace Grid.Northwind {
    public partial class Employee {
        public int EmployeeId { get; set; }
        [Required]
        public string LastName { get; set; }
        [Required]
        public string FirstName { get; set; }
        [Required]
        public string Title { get; set; }
        public string TitleOfCourtesy { get; set; }
        public Nullable<System.DateTime> BirthDate { get; set; }
        [Required]
        [Range(typeof(DateTime), "1/1/2000", "1/1/2020",
        ErrorMessage = "HireDate must be between {1:d} and {2:d}")]
        public Nullable<System.DateTime> HireDate { get; set; }
        public string Address { get; set; }
        public string City { get; set; }
        public string Region { get; set; }
        public string PostalCode { get; set; }
        public string Country { get; set; }
        public string HomePhone { get; set; }
        public string Extension { get; set; }
        public byte[] Photo { get; set; }
        public string Notes { get; set; }
        public Nullable<int> ReportsTo { get; set; }
        public string PhotoPath { get; set; }
        public virtual ICollection<Order> Orders { get; set; }
        public string Text => $"{FirstName} {LastName} ({Title})";
        public string ImageFileName => $"Employees/{EmployeeId}.jpg";
    }
}

NorthwindContext

using Microsoft.EntityFrameworkCore;
#nullable disable

namespace Grid.Northwind {
    public partial class NorthwindContext : DbContext {

        public NorthwindContext(DbContextOptions<NorthwindContext> options)
            : base(options) {
        }
        // ...
        public virtual DbSet<Employee> Employees { get; set; }

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder) {
            if(!optionsBuilder.IsConfigured) {
                optionsBuilder.UseSqlServer("Server=.\\sqlexpress;Database=Northwind;Integrated Security=true");
            }
        }

        protected override void OnModelCreating(ModelBuilder modelBuilder) {
            modelBuilder.HasAnnotation("Relational:Collation", "SQL_Latin1_General_CP1_CI_AS");
            // ...
            modelBuilder.Entity<Employee>(entity => {
                entity.HasIndex(e => e.EmployeeId, "EmployeeId");
                entity.HasIndex(e => e.LastName, "LastName");
                entity.HasIndex(e => e.FirstName, "FirstName");
                entity.HasIndex(e => e.Title, "Title");
                entity.HasIndex(e => e.BirthDate, "BirthDate");
                entity.HasIndex(e => e.HireDate, "HireDate");
                entity.HasIndex(e => e.Notes, "Notes");
            });
            OnModelCreatingPartial(modelBuilder);
        }

        partial void OnModelCreatingPartial(ModelBuilder modelBuilder);
    }
}

Program.cs

using Microsoft.EntityFrameworkCore;
// ...
builder.Services.AddDbContextFactory<NorthwindContext>((sp, options) => {
    var env = sp.GetRequiredService<IWebHostEnvironment>();
    var dbPath = Path.Combine(env.ContentRootPath, "Northwind-5e44b51f.mdf");
    options.UseSqlServer("Server=(localdb)\\MSSQLLocalDB;Integrated Security=true;AttachDbFileName=" + dbPath);
});