There are some ways to do it in WebForms, but first you need to make the DIV element of the dropdown menu accessible from the Code Behind.
See this snippet?
<ul class="nav nav-tabs">
<li class="nav-item dropdown">
<a class="btn btn-light dropdown-toggle" href="#" id="navbarDropdown1" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
Category
</a>
<div id="myDropdownMenu" runat="server" class="dropdown-menu" aria-labelledby="navbarDropdown">
</div>
</li>
</ul>
Note that I added 2 attributes : id="myDropdownMenu" and runat="server".
After this you can go to Code Behind to start populating the menu from a data source.
At least there are 2 ways to do this, as far as I know.
By manipulating the InnerHtml property, like this :
private void DisplayMenuByConstructingHtmlTags(List<string> menuList)
{
var menuHtml = "";
foreach (string menuText in menuList)
{
menuHtml += "<a class=\"dropdown-item\" href=\"#\">" + menuText + "</a>\n";
}
myDropdownMenu.InnerHtml = menuHtml;
}
Or, by adding the menu as the child controls, like this :
private void DisplayMenuByAddingChildControls(List<string> menuList)
{
foreach (string menuText in menuList)
{
var linkMenu = new HyperLink() { CssClass = "dropdown-item", NavigateUrl = "#", Text = menuText };
myDropdownMenu.Controls.Add(linkMenu);
}
}
It's your call, which one to choose.
Btw, just to complete this example, you may try to call one of those methods from the Page_Load event, like this :
EDIT :
By your request, I've modified the samples by adding a connection to a table in a database. So, this is the module to load the data :
private List<string> LoadMenuFromTable()
{
string connectionString = ConfigurationManager.ConnectionStrings["YourConnectionStringName"].ToString();
var retVal = new List<string>();
using (var connection = new SqlConnection(connectionString))
{
using (var cmd = new SqlCommand("SELECT menu_text FROM Table_1", connection))
{
connection.Open();
using (var reader = cmd.ExecuteReader())
{
while (reader.Read())
{
retVal.Add((string)reader["menu_text"]);
}
}
}
}
return retVal;
}
And here's how you should call the module :
protected void Page_Load(object sender, EventArgs e)
{
var menu = LoadMenuFromTable();
DisplayMenuByAddingChildControls(menu);
// or DisplayMenuByConstructingHtmlTags(menu);
}
Oh, and remember to import these two libraries to make this sample works :
using System.Configuration;
using System.Data.SqlClient;
Hope it helps.
