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Remove Items From a CheckBox List

Tags:

c#

asp.net

Here is main form:

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="CheckDelete.aspx.cs"  Inherits="CheckDelete" %>

 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org  /TR/xhtml1/DTD/xhtml1-transitional.dtd">

  <html xmlns="http://www.w3.org/1999/xhtml">
  <head runat="server">
  <title></title>
 </head>
<body>
<form id="form1" runat="server">
<asp:CheckBoxList ID="chkItems" runat="server" style="width: 37px">
    <asp:ListItem Value="A"></asp:ListItem>
    <asp:ListItem Value="B"></asp:ListItem>
    <asp:ListItem Value="C"></asp:ListItem>
    <asp:ListItem Value="D"></asp:ListItem>
    <asp:ListItem Value="E"></asp:ListItem>
    <asp:ListItem Value="F"></asp:ListItem>
    <asp:ListItem Value="H"></asp:ListItem>
</asp:CheckBoxList>
<asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="Delete" />
<br />
<br />
</form>

Code in Form:

protected void Button1_Click(object sender, EventArgs e)
{
    for (int i = 0; i < chkItems.Items.Count; i++)
    {
        if (chkItems.Items[i].Selected == true)
        {
           chkItems.Items.RemoveAt(i);
        }
    }

}

In my form, I want to delete the items that the user has checked off. However, if I select 3 items, at least one item will remain on the form after the user hits delete. What am I missing?

like image 690
Scott Anderson Avatar asked Dec 31 '25 13:12

Scott Anderson


1 Answers

You'll need to make a list of all the items you want to remove and then remove them one by one.

e.g.

List<ListItem> toBeRemoved = new List<ListItem>();
for(int i=0; i<chkItems.Items.Count; i++){
    if(chkItems.Items[i].Selected == true)
        toBeRemoved.Add(chkItems.Items[i]);
}

for(int i=0; i<toBeRemoved.Count; i++){
    chkItems.Items.Remove(toBeRemoved[i]);
}

In your example, you remove the items as you go which will change the index of the remaining items that you've yet to loop through. This will result with you "missing" items as you loop through. I imagine that's the cause of your problem.

like image 58
Grant Clements Avatar answered Jan 02 '26 01:01

Grant Clements