How do I populate dropdownlist inside Razor pages Not MVC

Question

How do I populate dropdownlist inside Razor pages Not MVC because
I have the code working fine in .Net core MVC but not working in .Net core Razor Page
How do I display the list in dropdown with asp-items="????????" i mean

How do I display from here

public IActionResult Droplist()  
   {  
        List<ListMode> _Define = PopulateList();  
        return View(new SelectList(_Define, "PredefineID", "Predefine"));  
    }  

return View(……); in above code is not working in Razor page

In side my Razor page I have this.

@Page  
@model…  
<form method="post">  
<select id="ddlFruits" name="PredefineID" asp-items="????????">  
<option value="0">Please select</option>  
</select>  
</form>  
                                  

Other part of the code
Database: dbo.DropListTBL

PredefineID	Predefine
1	Class
2	Subject
3	Option
4	Status

Model Class:

public class ListMode  
{  
    public int PredefineID { get; set; }  
    public string Predefine { get; set; }  
}  

Also:

private static List<ListMode> PopulateList()  
    {  
        string constr = @"Data Source =.; initial Catalog = DBname; Integrated Security = True";  
        List<ListMode> List_Mode = new List<ListMode>();  
        using (SqlConnection con = new SqlConnection(constr))  
        {  
            string query = "SELECT PredefineID, Predefine FROM dbo.DropListTBL";  
            using (SqlCommand cmd = new SqlCommand(query))  
            {  
                cmd.Connection = con;  
                con.Open();  
                using (SqlDataReader sdr = cmd.ExecuteReader())  
                {  
                    while (sdr.Read())  
                    {  
                        List_Mode.Add(new ListMode  
                        {  
                            Predefine = sdr["Predefine"].ToString(),  
                            PredefineID = Convert.ToInt32(sdr["PredefineID"])  
                        });  
                    }  
                }  
                con.Close();  
            }  
        }  

        return List_Mode;  
    }  

Answer 1

@Page  
@model…  
@{  
    var list = new SelectList(PopulateList(), "PredefineID", "Predefine"));  
}  
 <form method="post">  
   <select id="ddlFruits" name="PredefineID" asp-items="list">  
        <option value="0">Please select</option>  
   </select>  
 </form>  

you really should use async sql and put the init code OnGetAsync, and make the list part of the model

 @Page  
 @model…  
     <form method="post">  
       <select id="ddlFruits" name="PredefineID" asp-items="Model.FruitList">  
            <option value="0">Please select</option>  
       </select>  
     </form>  

and in PageModel:

public List<SelectListItem> FruitList {get; set;} = new  List<SelectListItem>;  
  
public async Task OnGetAsync()  
{  
   var data = await PopulateListAsync();  
   var list = new SelectList(data, "PredefineID", "Predefine"));  
}  

note: you should read the basic intro docs

Answer 2

Hi,@ladd4luv_22

I tried as below and it could work:
in pagemodel:

public class TestModel : PageModel  
    {  
        public SelectList DropDownList { get; set; }  
  
        public void OnGet()  
        {  
            var List_Mode = GetDropDownList();  
            DropDownList = new SelectList(List_Mode, "PredefineID", "Predefine");  
        }  
  
        //assuming you get the list successfully from db,I tried with hard coding  
        public List<ListMode> GetDropDownList()  
        {  
            var List_Mode = new List<ListMode>()   
            {  
            new ListMode(){PredefineID=1,Predefine="Class"},  
            new ListMode(){PredefineID=2,Predefine="Subject"},  
            new ListMode(){PredefineID=3,Predefine="Option"},  
            new ListMode(){PredefineID=4,Predefine="Status"}  
            };  
            return List_Mode;  
        }  
    }  

in page:

@page  
@model RazorPage7._22.Pages.TestModel  
  
<form method="post">  
    <select id="ddlFruits" name="PredefineID" asp-items="@Model.DropDownList">  
        <option value="0">Please select</option>  
    </select>  
</form>  

Result:

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Best regards
RuikaiFeng