How to get CheckBoxList selected values using Linq in asp.net

asp.net checkboxlist selected values linq

asp.net checkboxlist allow to select multiple items. in this example we see how to get the checkboxlist selected items. here we uses a simple linq query. when someone select an item from checkboxlist it will autopostback the page. then the linq query perform a query to get selected items list. after that a label control shows the checkboxlist selected items text and value by foreach loop.

checkboxlist-selected-values-linq.aspx


<%@ Page Language="C#" AutoEventWireup="true"%>    
      
<!DOCTYPE html>
        
<script runat="server">
    protected void Page_Load(object sender, EventArgs e)
    { 
        if(!Page.IsPostBack)
        {
            CheckBoxList1.Items.Add(new ListItem("Laughing Gull", "1"));
            CheckBoxList1.Items.Add(new ListItem("Swallow-tailed Gull", "2"));
            CheckBoxList1.Items.Add(new ListItem("Caspian Tern", "3"));
            CheckBoxList1.Items.Add(new ListItem("Roseate Tern", "4"));
            CheckBoxList1.Items.Add(new ListItem("Antarctic Tern", "5"));
        }
    }

    protected void CheckBoxList1_SelectedIndexChanged(object sender, EventArgs e)
    {
        // linq query to find selected items from checkboxlist
        var items = from ListItem li in CheckBoxList1.Items
                    where li.Selected == true
                    select li;

        Label1.Text = "you checked item(s).....<br />";

        foreach (ListItem li in items)
        {
            Label1.Text += "text: " + li.Text;
            Label1.Text += " <br /> value: " + li.Value + "<br /><br />";
        }
    }
</script>        
        
<html xmlns="http://www.w3.org/1999/xhtml">        
<head id="Head1" runat="server">        
    <title>asp.net checkboxlist selected values linq</title>
</head>        
<body>        
    <form id="form1" runat="server">        
    <div>        
        <h2 style="color:MidnightBlue; font-style:italic;">        
            asp.net example - checkboxlist selected values linq
        </h2>        
        <hr width="550" align="left" color="Gainsboro" />        
        <asp:Label       
            ID="Label1"       
            runat="server"      
            Text="check item(s) from checkboxlist."
            Font-Size="Medium"
            Width="350"
            >      
        </asp:Label>      
        <br /><br />
        <div class="block">
            <asp:CheckBoxList 
                ID="CheckBoxList1"
                runat="server"
                RepeatLayout="Table"
                RepeatColumns="2"
                AutoPostBack="true"
                OnSelectedIndexChanged="CheckBoxList1_SelectedIndexChanged"
                >
            </asp:CheckBoxList>  
        </div>
    </div>        
    </form>        
</body>        
</html>

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