按摩盒未显示实体框架核心

问题描述

嗨，我是Microsoft实体框架核心的新手，我使用（net核心3.1和Microsoft实体框架核心）创建了一个简单的Windows窗体应用程序，我已经成功创建了一个看起来像这样的表

    using AplicationDbContext DbContext = new AplicationDbContext();
            Wholesaler tabPage = new Wholesaler()
            {
                NameOwner = NameOwner.Text,NameCompany = NameCompany.Text,Address = Address.Text,MobilePhoneNumber1 =  MobilePhoneNumber1.Text,MobilePhoneNumber2 =  MobliePhoneNumber2.Text,linePhone1 = LinePhone1.Text,linePhone2 = LinePhone2.Text,Email = Email.Text,Fax = Fax.Text
            };
DbContext.Wholesalers.Add(tabPage);
            DbContext.SaveChanges();

问题是NameCompany为PK，我想向用户“ Name Company已经存在”显示按摩框，并防止出现此错误（sqlException：违反PRIMARY KEY约束'PK_Wholesalers'。无法在对象'中插入重复的键dbo.Wholesalers'。重复的键值为（）。）

解决方法

using AplicationDbContext DbContext = new AplicationDbContext();
        
            Wholesaler tabPage = new Wholesaler()           
        {
            NameOwner = NameOwner.Text,NameCompany = NameCompany.Text,Address = Address.Text,MobilePhoneNumber1 =  MobilePhoneNumber1.Text,MobilePhoneNumber2 =  MobliePhoneNumber2.Text,linePhone1 = LinePhone1.Text,linePhone2 = LinePhone2.Text,Email = Email.Text,Fax = Fax.Text
        };
        if (DbContext.Wholesalers.Any(s => s.NameCompany == NameCompany.Text))
        {
            MessageBox.Show($"Wholesaler: {NameCompany.Text} already exist ","Name Company",MessageBoxButtons.OK,MessageBoxIcon.Information);
            return;
        }
        DbContext.Wholesalers.Add(tabPage);
        DbContext.SaveChanges();
    }

在这里Check if Record Exists in Entity Framework

找到了答案