How to create input field dropdown list from database in ASP.NET?

Question

I'm using ASP.NET 4.8. I'm using the code below to show a dropdown list from database (.aspx file). What do I need to do create an input text field, that shows a dropdown list after the user types something in it? I found a tutorial with AJAX devexpress, but it doesn't run on Visual Studio 2022. The project is shown on a website. Page Language="vb"

<tr>
                                            <td style="font-size:Large;">
                                                Raba tal <b>2018</b>:
                                            </td>
                                            <td>
                                                <asp:DropDownList ID="raba3"  runat="server" DataSourceID="dsSifRaba" DataTextField="mnaziv" DataValueField="raba" SelectedValue='<%# Bind("raba3")%>' OnDataBound="raba3_DataBound" Font-Size="Large" CssClass="ui-widget" ></asp:DropDownList>
                                                <asp:RequiredFieldValidator ID="rfRaba3" runat="server" ErrorMessage="Obvezno polje" ControlToValidate="raba3" CssClass="validator" Display="Dynamic"></asp:RequiredFieldValidator>

                                            </td>
                                        </tr>

Answer 1

Hi @Aleks Mavrič ,
You can try to download nuget package --AjaxControlToolkit to create input field dropdown.

You can refer to the example below.

<ajaxToolkit:ComboBox ID="cbCustomers" runat="server" AutoCompleteMode="SuggestAppend">  
</ajaxToolkit:ComboBox>  

Imports System.Data  
Imports System.Data.SqlClient  
  
Partial Class _Default  
    Inherits System.Web.UI.Page  
    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load  
        Using con As SqlConnection = New SqlConnection("Data Source=***")  
  
            Using cmd As SqlCommand = New SqlCommand("SELECT * FROM Products", con)  
  
                Dim sda As SqlDataAdapter = New SqlDataAdapter(cmd)  
                Dim dt As DataTable = New DataTable()  
                sda.Fill(dt)  
                cbCustomers.DataSource = dt  
                cbCustomers.DataTextField = "ProductName"  
                cbCustomers.DataValueField = "ProductID"  
                cbCustomers.DataBind()  
            End Using  
        End Using  
    End Sub  
    Protected Sub Submit(ByVal sender As Object, ByVal e As EventArgs)  
        Dim message As String = "Selected Text: " & cbCustomers.SelectedItem.Text  
        message += "\nSelected Value: " & cbCustomers.SelectedItem.Value  
        ClientScript.RegisterStartupScript(Me.[GetType](), "alert", "alert('" & message & "');", True)  
    End Sub      
End Class  

Best regards,
Lan Huang

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Answer 2

Thank you! Didn't found a solution like that, however I still have a problem.

I have used the attribute DataValueField="raba"

I have changed this:

To this:

But I still get an error message.

Do you have any suggestions on what do I have to fix here?