In this article I will explain with an example, how to pass (send) DropDownList value using QueryString in ASP.Net using C# and VB.Net.
The DropDownList value will be read and added as QueryString parameter and the Page will be redirected and then on another Page the DropDownList value will be read from QueryString and displayed on Page in ASP.Net using C# and VB.Net.
 
 
Passing (Sending) DropDownList value using QueryString in ASP.Net
HTML Markup
The HTML Markup consists of an ASP.Net TextBox, a DropDownList and a Button.
Name:
<asp:TextBox ID = "txtName" runat="server" Text = "Mudassar Khan" />
<br />
<br />
Technology:
<asp:DropDownList ID = "ddlTechnology" runat="server">
    <asp:ListItem Text="ASP.Net" Value = "ASP.Net" />
    <asp:ListItem Text="PHP" Value = "PHP" />
    <asp:ListItem Text="JSP" Value = "JSP" />
</asp:DropDownList>
<asp:Button ID="btnSend" Text="Send" runat="server" OnClick = "Send" />
 
Code
When the Send Button is clicked, the Name and Technology values are fetched from the TextBox and DropDownList controls and are set in the URL as QueryString parameters and the Page is redirected.
C#
protected void Send(object sender, EventArgs e)
{
    string name = txtName.Text;
    string technology = ddlTechnology.SelectedItem.Value;
    Response.Redirect(string.Format("~/Page2.aspx?name={0}&technology={1}", name, technology));
}
 
VB.Net
Protected Sub Send(sender As Object, e As System.EventArgs)
    Dim name As String = txtName.Text
    Dim technology As String = ddlTechnology.SelectedItem.Value
    Response.Redirect(String.Format("~/Page2.aspx?name={0}&technology={1}", name, technology))
End Sub
 
 
Reading DropDownList value sent using QueryString and displaying in ASP.Net
HTML Markup
The HTML Markup consists of an ASP.Net Label.
<asp:Label ID="lblData" runat="server" />
 
Code
Inside the Page Load event, the Name and Technology values are fetched from the QueryString and displayed in Label control.
C#
protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        string name = Request.QueryString["name"];
        string technology = Request.QueryString["technology"];
        string data = "<u>Values from QueryString</u><br /><br />";
        data += "<b>Name:</b> " + name + " <b>Technology:</b> " + technology;
        lblData.Text = data;
    }
}
 
VB.Net
Protected Sub Page_Load(sender As Object, e As System.EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Dim name As String = Request.QueryString("name")
        Dim technology As String = Request.QueryString("technology")
        Dim data As String = "<u>Values from QueryString</u><br /><br />"
        data &= "<b>Name:</b> " & name & " <b>Technology:</b> " & technology
        lblData.Text = data
    End If
End Sub
 
 
Screenshot
Pass (Send) DropDownList value using QueryString in ASP.Net using C# and VB.Net
 
 
Demo
 
 
Downloads