ASP.Net DropDownList FindByText FindByValue Error: Object reference not set to an instance of an object

Hey nauna,

Please refer below smaple.

HTML

Login.aspx

<div>
    Name:
    <asp:TextBox runat="server" ID="txtName" />
    <asp:Button Text="LoginUser" runat="server" OnClick="Loginn" />
</div>

CS.aspx

<div>
    <asp:DropDownList runat="server" ID="ddlCountry">
        <asp:ListItem Text="Select Country" />
        <asp:ListItem Text="USA" Value="USA" />
        <asp:ListItem Text="Russia" Value="Russia" />
        <asp:ListItem Text="India" Value="India" />
    </asp:DropDownList>
</div>

Namespaces

C#

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

VB.Net

Imports System.Data.SqlClient
Imports System.Data

Code

C#

Login.aspx.cs

protected void Loginn(object sender, EventArgs e)
{
    using (SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["constr"].ConnectionString))
    {
        using (SqlCommand cmd = new SqlCommand("SELECT EmployeeId, FirstName FROM Employees", conn))
        {
            using (SqlDataAdapter da = new SqlDataAdapter(cmd))
            {
                using (DataTable dt = new DataTable())
                {
                    da.Fill(dt);
                    foreach (DataRow row in dt.Rows)
                    {
                        if (txtName.Text == row["FirstName"].ToString())
                        {
                            Session["Name"] = txtName.Text;
                            Response.Redirect("CS.aspx");
                        }
                    }
                }
            }
        }
    }
}

CS.aspx.cs

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        string country = GetCountryBasedOnLogedInUser();

        if (ddlCountry.Items.FindByText(GetCountryBasedOnLogedInUser()) != null)
        {
            ddlCountry.Items.FindByText(GetCountryBasedOnLogedInUser()).Selected = true;
        }
    }
}

private string GetCountryBasedOnLogedInUser()
{
    using (SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["constr"].ConnectionString))
    {
        string query = "SELECT Country FROM Employees WHERE FirstName = @FirstName";
        SqlCommand cmd = new SqlCommand(query, conn);
        cmd.Parameters.AddWithValue("@FirstName", Session["Name"]);
        conn.Open();
        string country = Convert.ToString(cmd.ExecuteScalar());
        conn.Close();
        return country;
    }
}

VB.Net

Login.aspx.vb

Protected Sub Loginn(ByVal sender As Object, ByVal e As EventArgs)
    Using conn As SqlConnection = New SqlConnection(ConfigurationManager.ConnectionStrings("constr").ConnectionString)
        Using cmd As SqlCommand = New SqlCommand("SELECT EmployeeId, FirstName FROM Employees", conn)
            Using da As SqlDataAdapter = New SqlDataAdapter(cmd)
                Using dt As DataTable = New DataTable()
                    da.Fill(dt)
                    For Each row As DataRow In dt.Rows
                        If txtName.Text = row("FirstName").ToString() Then
                            Session("Name") = txtName.Text
                            Response.Redirect("VB.aspx")
                        End If
                    Next
                End Using
            End Using
        End Using
    End Using
End Sub

VB.aspx.vb

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Dim country As String = GetCountryBasedOnLogedInUser()
        If ddlCountry.Items.FindByText(GetCountryBasedOnLogedInUser()) IsNot Nothing Then
            ddlCountry.Items.FindByText(GetCountryBasedOnLogedInUser()).Selected = True
        End If
    End If
End Sub

Private Function GetCountryBasedOnLogedInUser() As String
    Using conn As SqlConnection = New SqlConnection(ConfigurationManager.ConnectionStrings("constr").ConnectionString)
        Dim query As String = "SELECT Country FROM Employees WHERE FirstName = @FirstName"
        Dim cmd As SqlCommand = New SqlCommand(query, conn)
        cmd.Parameters.AddWithValue("@FirstName", Session("Name"))
        conn.Open()
        Dim country As String = Convert.ToString(cmd.ExecuteScalar())
        conn.Close()
        Return country
    End Using
End Function

Screenshot