普通的增删改查list View与LinQ:集成化语言增删改查与扩展属性

普通增加：

SqlConnection conn = new SqlConnection("server=.;database=mydb;uid=sa;pwd=789234178");
 SqlCommand cmd = conn.CreateCommand();

cmd.CommandText = "insert into fruit values(@Ids,@Name,@Price,@Source,@Numbers,@Image)";

cmd.Parameters.Add("@Ids", textBox1.Text);
 cmd.Parameters.Add("@Name", textBox2.Text);
 cmd.Parameters.Add("@Price", textBox3.Text);
 cmd.Parameters.Add("@Source", textBox4.Text);
 cmd.Parameters.Add("@Numbers", textBox5.Text);
 cmd.Parameters.Add("@Image", textBox6.Text);

conn.Open();
 cmd.ExecuteNonQuery();
 conn.Close();

List View控件：

要想从List View中显示列表，首先要从属性中最下面的View中

改为Details是专门用来显示列表的

属性中columns集合是用来显示列，Items是用来显示每一行，在text里面填写数据

在List View中查询：

SqlConnection conn = new SqlConnection("server=.;database=mydb;uid=sa;pwd=789234178");
 SqlCommand cmd = conn.CreateCommand();
 cmd.CommandText = "select*from fruit";
 conn.Open();
 SqlDataReader dr = cmd.ExecuteReader();

 while (dr.Read())
 { 
 ListViewItem lvt=new ListViewItem();
 lvt.Text=dr["ids"].ToString();
 lvt.SubItems.Add(dr["name"].ToString());
 lvt.SubItems.Add(dr["price"].ToString());
 lvt.SubItems.Add(dr["source"].ToString());
 lvt.SubItems.Add(dr["numbers"].ToString());
 lvt.SubItems.Add(dr["image"].ToString());
 listView1.Items.Add(lvt);
 }
 conn.Close();

 在List View中删除：

在List view中要想删除一行但只能选择一个单元格的情况下从属性里面找到FullrowSelect选中True就可以选择一行删除了。

LinQ:集成化语言增删改查 O--M--R Object:对象   Mapping:映射   Relation:关系

用法： 一、简单的查询

造一个上下文对象：

  HRDataContext _context = new HRDataContext();

扩展方法，查所有

dataGridView1.DataSource = _context.Info;

根据条件查,括号里要写Lambda表达式      

List<Info> list = _context.Info.Where(p=>p.列名=="p001" || p.Name=="张三").ToList();

二、添加数据：

1.造一个上下文对象  HRDataContext _context = new HRDataContext();

2.造对象           Info data = new Info();       

                      data.Code = "p005";

                      data.Name = "张三";

                      data.Sex = true;

                     data.Nation = "n001";   

                     data.Birthday = DateTime.Now;

3.添加

_context.Info.InsertOnSubmit(data);

4.提交  

_context.SubmitChanges();

三、修改对象

1.造一个上下文对象

方法一：

HRDataContext _context = new HRDataContext();

2.找出要修改的对象

List<Info> list = _context.Info.Where(p=>p.Code=="p005").ToList();

3.判断有没有找出数据

            if (list.Count > 0)            

{                 Info data = list.First();

                data.Name = "李四";

提交修改

_context.SubmitChanges();

方法二：

  var query = _context.Info.Where(p => p.Code == "p001");

            Info data = query.First();

            data.Name = "aa";

            _context.SubmitChanges();

四、删除对象

方法一：

1.造一个上下文对象

HRDataContext _context = new HRDataContext();

2.找出要修改的对象

List<Info> list = _context.Info.Where(p => p.Code == "p001").ToList();

3.判断有没有找出数据

         if (list.Count > 0)           

  {                 Info data = list.First();

              删除             

    _context.Family.DeleteAllOnSubmit(data.Family);              

    _context.Work.DeleteAllOnSubmit(data.Work);                

    _context.Info.DeleteOnSubmit(data);            

}

4.提交

 _context.SubmitChanges();

方法二：

 //var query = _context.Info.Where(p=>p.Code=="p001");           

  //Info data = query.First();

            var query1 = _context.Family.Where(p => p.InfoCode == data.Code);         

    _context.Family.DeleteAllOnSubmit(query1);

            var query2 = _context.Work.Where(p => p.InfoCode == data.Code);     

        _context.Work.DeleteAllOnSubmit(query2);

            _context.Info.DeleteOnSubmit(data);

            _context.SubmitChanges();

扩展属性：

 partial class Info  

   {     

    public string SexName      

   {          

   get {               

  return this.Sex.Value ? "男" : "女";        

     }      

   }

        public string NationName      

   {             get {           

      //TestDataContext context = new TestDataContext();

                //Nation data = context.Nation.Where(p=>p.Code == this.Nation).First();

                //return data.Name;

                return this.Nation1.Name;         

    }       

  }    

} }