In this article I will explain with an example, how to make the First (Default) item (option) not Selectable in ASP.Net DropDownList using C# and VB.Net.
Generally, DropDownList controls have a default first item (option) such as “Please select” which is not meant to be selected and hence using this technique user will not be able to select the First (Default) item (option) in the ASP.Net DropDownList.
 
 

Database

I have made use of the following table Customers with the schema as follows.
Make First (Default) item (option) not Selectable in ASP.Net DropDownList using C# and VB.Net
 
I have already inserted few records in the table.
Make First (Default) item (option) not Selectable in ASP.Net DropDownList using C# and VB.Net
 
Note: You can download the database table SQL by clicking the download link below.
            Download SQL file
 
 

HTML Markup

The HTML Markup consists of an ASP.Net DropDownList which will be populated from database.
<asp:DropDownList ID="ddlCustomers" runat="server">
</asp:DropDownList>
 
 

Namespaces

You will need to import the following namespaces.
C#
using System.Data;
using System.Configuration;
using System.Data.SqlClient;
 
VB.Net
Imports System.Data
Imports System.Configuration
Imports System.Data.SqlClient
 
 

Make First (Default) item (option) not Selectable in ASP.Net DropDownList

Inside the Page Load event of the page, the DropDownList is populated with the records of the Customers Table using SqlDataReader.
Note: For more details about populating DropDownList using SqlDataReader, please refer my article Bind (Populate) ASP.Net DropDownList using DataReader in C# and VB.Net.
 
Once the records from database are populated, a default item (option) is inserted at the first position and is marked as Selected.
Finally, the default item (option) is disabled (not selectable) by adding HTML disabled attribute.
C#
protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
        using (SqlConnection con = new SqlConnection(constr))
        {
            using (SqlCommand cmd = new SqlCommand("SELECT CustomerId, Name FROM Customers"))
            {
                cmd.CommandType = CommandType.Text;
                cmd.Connection = con;
                con.Open();
                ddlCustomers.DataSource = cmd.ExecuteReader();
                ddlCustomers.DataTextField = "Name";
                ddlCustomers.DataValueField = "CustomerId";
                ddlCustomers.DataBind();
                con.Close();
            }
        }
 
        //Add a default item at first position.
        ddlCustomers.Items.Insert(0, new ListItem("Please select", ""));
 
        //Set the default item as selected.
        ddlCustomers.Items[0].Selected = true;
 
        //Disable the default item.
        ddlCustomers.Items[0].Attributes["disabled"] = "disabled";
    }
}
 
VB.Net
Protected Sub Page_Load(sender As Object, e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
        Using con As New SqlConnection(constr)
            Using cmd As New SqlCommand("SELECT CustomerId, Name FROM Customers")
                cmd.CommandType = CommandType.Text
                cmd.Connection = con
                con.Open()
                ddlCustomers.DataSource = cmd.ExecuteReader()
                ddlCustomers.DataTextField = "Name"
                ddlCustomers.DataValueField = "CustomerId"
                ddlCustomers.DataBind()
                con.Close()
            End Using
        End Using
 
        'Add a default item at first position.
        ddlCustomers.Items.Insert(0, New ListItem("Please select", ""))
 
        'Set the default item as selected.
        ddlCustomers.Items(0).Selected = True
 
        'Disable the default item.
        ddlCustomers.Items(0).Attributes("disabled") = "disabled"
    End If
End Sub
 
 

Screenshot

Make First (Default) item (option) not Selectable in ASP.Net DropDownList using C# and VB.Net
 
 

Browser Compatibility

The above code has been tested in the following browsers.
Microsoft Edge   FireFox  Chrome  Safari  Opera
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Demo

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Downloads

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