How to Get the selected Item id in list box using Linq Query

You need to make sure the value is not null before applying ToString() to it:

string s = ""; // default value, say, if SelectedValue is null

if (listBox1.SelectedValue != null)
{
  s = listBox1.SelectedValue.ToString();
}

Hi 

This is the code segment which can help you out somewhere :

<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): 
");
    foreach (var item in selItems)
    {
        Response.Write(item.ToString() + "
");
    }
}

You can also refer this link :

 http://www.devcurry.com/2009/07/retrieve-selected-items-of-aspnet.html



Cheers DotNet :)

Assuming that RegistrationNo is a property of whatever class 's' belongs to then , if you change the first line to this then it should work:

var names = (from s in dbc.Patient_Detail_Tables where s.Name.Contains(txtSearch.Text) select s).ToList();