.net EF框架-实现增删改查

//申明一个表的实体线
Contact contact = new Contact();
//向表中的字段名加上数据信息
contact.Name = "张三";
contact.EnrollmentDate = DateTime.Now;
//做插进操作
dbContext.Contacts.Add(contact);
 //储存
dbContext.SaveChanges();

//申明一个表的实体线
Contact contact = new Contact();
contact.Name = "张三三";
contact.EnrollmentDate = DateTime.Now;
contact.ID = 3;  //改动或删掉操作时选填字段名
//做改动操作
dbContext.Entry<Contact>(contact).State=System.Data.Entity.EntityState.Modified;
//储存
dbContext.SaveChanges();

//删掉ID为3的一条数据信息
Contact contact = dbContext.Contacts.Find(3);
dbContext.Contacts.Remove(contact);
dbContext.SaveChanges();

 List<Contact> list = dbContext.Contacts.ToList();

List<Contact> list = dbContext.Contacts.Where(u => u.Name == "东莞市").ToList();

Contact contact = dbContext.Contacts.Find(30);

int _Page=3;  //第几页
int _Take = 5;  //每张显示信息是多少条数据信息
List<Contact> result = dbContext.Contacts.Where(a => a.Name == "东莞市").OrderBy(a => a.ID).Skip(_Take * (_Page - 1)).Take(_Take).ToList();

//Contains等额的于数据库查询 like '%key%'特定的字符串数组目标是不是出現在字符串数组中
//EndsWith等额的于数据库查询 like '%key'  字符串数组目标末尾是不是与特定字符串匹配
//StartsWith等额的于数据库查询 like 'key%'字符串数组目标开始是不是与特定字符串匹配
List<Contact> result = dbContext.Contacts.Where(a => a.Name.Contains("东莞市") || a.Name.EndsWith("2")).ToList();

 public partial class Model : DbContext
 {
     public Model()
         : base("name=efdemo")
     {
     }
     public virtual DbSet<Contact> Contacts { get; set; }
}

 public class Contact
 {
    public int ID { get; set; }
    public string Name { get; set; }
    public DateTime EnrollmentDate { get; set; }
    public virtual ICollection<Enrollment> Enrollments { get; set; }
 }