LinQ 组合查询与分页

1.以开头查

public List<Car> Select1(string a){

return con.Car.Where(r => r.Name.StartsWith(a)).ToList();
}

2.以结尾查

public List<Car> Select2(string a)

{
return con.Car.Where(r => r.Name.EndsWith(a)).ToList();
}

3.最大值

public string Max()

{
return con.Car.Max(r => r.Price).ToString();
}

4.最小值

public string Min()

{
return con.Car.Min(r => r.Price).ToString();
}

5.总和

public string Sum()
{
return con.Car.Sum(r => r.Price).ToString();
}

6.平均值

public string avg()
{
return con.Car.Average(r => r.Price).ToString();
}

7.升序

public List<Car> ss()
{
return con.Car.OrderBy( r =>r.Price).ToList();
}

8.降序

public List<Car> s()
{
return con.Car.OrderByDescending(r => r.Price).ToList();
}

9.组合分页查询

  public List<Car> Selecta(int d, string a, string b, string c)  {    List<Car> list = new List<Car>();    list = con.Car.ToList();   if (a != "")    {      List<Car> list1 = con.Car.Where(r => r.Code.Contains(a)).ToList();      list = list.Intersect(list1).ToList();    }    if (b != "")    {      List<Car> list1 = con.Car.Where(r => r.Name.Contains(b)).ToList();      list = list.Intersect(list1).ToList();    }    if (c != "")    {      List<Car> list1 = con.Car.Where(r => r.Brand.Contains(c)).ToList();      list = list.Intersect(list1).ToList();    }    return list.Skip((d-1-1) * PageCount).Take(PageCount).ToList();      }  int PageCount = 6;  public List<Car> start()  {    return con.Car.Skip(0 * PageCount).Take(PageCount).ToList();  }  public List<Car> prev(string a)  {    return con.Car.Skip((Convert.ToInt32(a) - 1 - 1) * PageCount).Take(PageCount).ToList();  }  public List<Car> next(string a)  {    return con.Car.Skip(Convert.ToInt32(a) * PageCount).Take(PageCount).ToList();  }  public List<Car> end()  {    return con.Car.Skip((max() - 1) * PageCount).Take(PageCount).ToList();  }  private int max()  {    int count = new CarData().Select().Count;    double aa = count / (PageCount * 1.0);    return Convert.ToInt32(Math.Ceiling(aa));  }}

 void LinkButton4_Click(object sender, EventArgs e)  {    Repeater1.DataSource = new CarData().end();    Repeater1.DataBind();    Label2.Text = max().ToString();  }    private int max()  {    int count = new CarData().Select().Count;    double aa = count / (PageCount * 1.0);    return Convert.ToInt32(Math.Ceiling(aa));  }  void LinkButton3_Click(object sender, EventArgs e)  {    if (Convert.ToInt32(Label2.Text) < max())    {      int a = Convert.ToInt32(Label2.Text) + 1;      Repeater1.DataSource = new CarData().next(Label2.Text);      Repeater1.DataBind();      Label2.Text = a.ToString();    }    else    {      return;    }  }  void LinkButton2_Click(object sender, EventArgs e)  {        if (Convert.ToInt32(Label2.Text) > 1)    {      int a = Convert.ToInt32(Label2.Text) - 1;      Repeater1.DataSource = new CarData().prev(Label2.Text);      Repeater1.DataBind();      Label2.Text = a.ToString();    }    else    {      return;    }  }  void LinkButton1_Click(object sender, EventArgs e)//首页  {    Repeater1.DataSource = new CarData().start();    Repeater1.DataBind();    Label2.Text = "1";  }  void Button13_Click(object sender, EventArgs e)  {    Label2.Text = "1";    int a = Convert.ToInt32(Label2.Text) + 1;    Repeater1.DataSource = new CarData().Selecta(a,TextBox3.Text, TextBox4.Text, TextBox5.Text);    Repeater1.DataBind();        int count = new CarData().Select().Count;        Label3.Text = Math.Ceiling(Convert.ToDouble(count) / PageCount).ToString();      }

原标题：LinQ 组合查询与分页

关键词：linq