How to retrieve database data on selected attribute with foreach loop?

Question

User-578960655 posted

Hi, i want to know how to listed/retrieve data from selected database table with foreach loop, but without showing ALL data instead i want to show selected data only. 

Example on html syntax, call it MenuList.cshtml

       @foreach (var item in Model.Menu)
        {
            <tr>
                <td>
                    @Html.DisplayFor(modelItem => item.Breakfast)
                </td>

DbController.cs

        public static List<Menu> LoadMenu()
        {
            string sql = @"select MenuID, Breakfast from dbo.Menu;";

            return SqlDataAccess.LoadData<Menu>(sql);
        }

MenuList.cshtml.cs

        public ActionResult ViewMenu()
        {
            ViewBag.Message = "Menu List";

            var data = LoadMenu();
            List<Menu> menu = new List<Menu>();

            foreach(var row in data)
            {
                menu.Add(new Menu
                {
                    Breakfast = row.Breakfast
                });
            }
            return Page();
        }

In Menu.cs, i provided 3 data in Breakfast attribute. I would like to show only 1 from 3 data. How should i limit the foreach loop?

Answer 1

User303363814 posted

Change your sql so it only retrieves the rows that you want.

select MenuID, Breakfast from dbo.Menu where ….

Answer 2

User-2054057000 posted

You could use a LINQ query with Where condition after this something like:

SqlDataAccess.LoadData<Menu>(sql).Where(t => t.Name =="Jack");

Answer 3

User1686398519 posted

Hi,  emirryhn

You can use "if" in your loop to judge based on a certain condition.

data.ForEach(m =>
{
     if (m.MenuID == 1)
     {
          menu.Add(new Menu { Breakfast = m.Breakfast });
     }
});

OR

foreach (var row in data)
            {
                if (row.MenuID == 1)
                {
                    menu.Add(new Menu
                    {
                        Breakfast = row.Breakfast
                    });
             }
}

Here is the result.

 
Best Regards,

YihuiSun