Retrieve Selected Items of an ASP.NET ListBox using LINQ

I had recently written a post on Programmatically Select Multiple Items of an ASP.NET ListBox. A user ‘JukeBox’ mailed back asking me if it was possible to retrieve the selected items of a ListBox using LINQ. Here’s how to do so:

<div>
    <asp:ListBox ID="ListBox1" runat="server" SelectionMode="Multiple">
        <asp:ListItem Value="One" Selected="True" />
        <asp:ListItem Value="Two" />
        <asp:ListItem Value="Three" />
        <asp:ListItem Value="Four" Selected="True" />
        <asp:ListItem Value="Five" />
    </asp:ListBox>
    <br />
    <br />
    <asp:Button ID="btnSel" runat="server" Text="Get Selected"
        onclick="btnSel_Click" />
</div>

C#

protected void btnSel_Click(object sender, EventArgs e)
{
    var selItems = from ListItem li in ListBox1.Items
                   where li.Selected == true
                   select li.Text;

    Response.Write("Selected Item(s): </br>");
    foreach (var item in selItems)
    {
        Response.Write(item.ToString() + "</br>");
    }
}

VB.NET

Protected Sub btnSel_Click(ByVal sender As Object, ByVal e As EventArgs)
    Dim selItems = _
     From li As ListItem In ListBox1.Items _
     Where li.Selected = True _
     Select li.Text

    Response.Write("Selected Item(s): </br>")
    For Each item In selItems
        Response.Write(item.ToString() & "</br>")
    Next item
End Sub

On clicking the Button, the selected items are fetched as shown below:

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About The Author

Suprotim Agarwal, ASP.NET Architecture MVP works as an Architect Consultant and provides consultancy on how to design and develop Web applications.

Suprotim is also the founder and primary contributor to DevCurry, DotNetCurry and SQLServerCurry. He has also written an EBook 51 Recipes using jQuery with ASP.NET Controls.

Follow him on twitter @suprotimagarwal