Hello I am new to MVC and webdevelopment and I am stuck with Viewbag I am trying to populate dropdownlist with names from a staff tableHere is a method that is meant to get the namespublic Listltstringgt GetStaffList using SqlConnection conn new SqlConnectionConnection var command new SqlCommandGetReadQuery conn connOpen var result StringEmpty var reader commandExecuteReader staff staffTbl new staff i

Bind (Populate) DropDownListFor using ViewBag in ASP.Net MVC

leila398

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User: leila398
Posted: on Nov 16, 2021 02:42 AM
Forum: ASP.Net MVC
Answer: 1
Views: 2446
Sample Code: Download

Hello I am new to MVC and webdevelopment and I am stuck with Viewbag. I am trying to populate dropdownlist with names from a staff table.

Here is a method that is meant to get the names:

public List<string> GetStaffList()
{
    using (SqlConnection conn = new SqlConnection(_Connection))
    {
        var command = new SqlCommand(GetReadQuery(), conn);
        conn.Open();
 
        var result = String.Empty;
        var reader = command.ExecuteReader();
 
       staff staffTbl = new staff();
 
        if (reader.HasRows)
        {
            while (reader.Read())
            {
                reader.Read();
                DropDownList.Add(reader["name"].ToString());
            }
        }
        conn.Close();
        return DropDownList;
    }
}

When I step through it looks like DropDownList stores all the items as I can see the count and names. But it eventually throws an error saying Invalid attempt to read when no data is present.

Here is the controller calling this method:

public ActionResult DropdownList()
{
    var dropdowngenerator = new DropdownGenerator(connString);
    var getList = dropdowngenerator.GetStaffList().ToList();
 
    SelectList list = new SelectList(getList);
    ViewBag.StaffList = list;
 
    return View();
}

And then here is the View with the dropdownlist:

<div class="form-group">
        @Html.LabelFor(model => model.staffname, htmlAttributes: new { @class = "control-label col-md-2" })
    <div class="col-md-10">
        @Html.DropDownListFor(model => model.staffname, (SelectList)ViewBag.StaffL)
        @Html.ValidationMessageFor(model => model.staffname, "", new { @class = "text-danger" })
    </div>
 </div>

Please help I would be very grateful

dharmend...

0 3

Reply
ANSWER
User: dharmendr
Replied: on Nov 16, 2021 03:13 AM
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Hi leila398,

Check this example. Now please take its reference and correct your code.

Database

For this example I have used of Northwind database that you can download using the link given below.

Download Northwind Database

Model

public class staff
{
    public int Id { get; set; }
    public string staffname { get; set; }
}

Namespaces

using System.Configuration;
using System.Data.SqlClient;

Controller

public class HomeController : Controller
{
    // GET: Home
    public ActionResult Index()
    {
        SelectList list = new SelectList(GetStaffList(), "Id", "staffname");
        ViewBag.StaffList = list;
        return View();
    }

    public List<staff> GetStaffList()
    {
        string _Connection = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
        using (SqlConnection conn = new SqlConnection(_Connection))
        {
            var command = new SqlCommand("SELECT EmployeeID,FirstName FROM Employees", conn);
            conn.Open();
            SqlDataReader reader = command.ExecuteReader();
            List<staff> staffTbl = new List<staff>();
            while (reader.Read())
            {
                staffTbl.Add(new staff
                {
                    Id = Convert.ToInt32(reader["EmployeeID"]),
                    staffname = reader["FirstName"].ToString()
                });
            }
            conn.Close();

            return staffTbl;
        }
    }
}

View

@model ViewBag_DropDownList_MVC.Models.staff
@{
    Layout = null;
}

<!DOCTYPE html>

<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title>Index</title>
</head>
<body>
    @Html.LabelFor(model => model.staffname)
    @Html.DropDownListFor(model => model.staffname, (IEnumerable<SelectListItem>)ViewBag.StaffList, "Select")
</body>
</html>

Screenshot

Bind (Populate) DropDownListFor using ViewBag in ASP.Net MVC

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