Retrieve Selected Items of an ASP.NET ListBox using LINQ

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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, Developer Technologies MVP (Microsoft Most Valuable Professional) is the founder and contributor for DevCurry, DotNetCurry and SQLServerCurry. He is the Chief Editor of a Developer Magazine called DNC Magazine. He has also authored two Books - 51 Recipes using jQuery with ASP.NET Controls. and The Absolutely Awesome jQuery CookBook.

Follow him on twitter @suprotimagarwal.