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How to get values of selected items in CheckBoxList with foreach in ASP.NET C#?

Posted by: admin November 29, 2017 Leave a comment

Questions:

I have a CheckBoxList like this:

<asp:CheckBoxList ID="CBLGold" runat="server" CssClass="cbl">
    <asp:ListItem Value="TGJU"> TG </asp:ListItem>
    <asp:ListItem Value="GOLDOZ"> Gold </asp:ListItem>
    <asp:ListItem Value="SILVEROZ"> Silver </asp:ListItem>
    <asp:ListItem Value="NERKH"> NE </asp:ListItem>
    <asp:ListItem Value="TALA"> Tala </asp:ListItem>
    <asp:ListItem Value="YARAN"> Sekeh </asp:ListItem>
</asp:CheckBoxList>

Now I want to get the value of the selected items from this CheckBoxList using foreach, and put the values into a list.

Note: I would prefer the code to be short.

Answers:

Note that I prefer the code to be short.

List<ListItem> selected = CBLGold.Items.Cast<ListItem>()
    .Where(li => li.Selected)
    .ToList();

or with a simple foreach:

List<ListItem> selected = new List<ListItem>();
foreach (ListItem item in CBLGold.Items)
    if (item.Selected) selected.Add(item);

If you just want the ListItem.Value:

List<string> selectedValues = CBLGold.Items.Cast<ListItem>()
   .Where(li => li.Selected)
   .Select(li => li.Value)
   .ToList();

Questions:
Answers:

Good afternoon, you could always use a little LINQ to get the selected list items and then do what you want with the results:

var selected = CBLGold.Items.Cast<ListItem>().Where(x => x.Selected);
// work with selected...

Questions:
Answers:
        foreach (ListItem item in CBLGold.Items)
        {
            if (item.Selected)
            {
                string selectedValue = item.Value;
            }
        }

Questions:
Answers:

Following suit from the suggestions here, I added an extension method to return a list of the selected items using LINQ for any type that Inherits from System.Web.UI.WebControls.ListControl.

Every ListControl object has an Items property of type ListItemCollection. ListItemCollection exposes a collection of ListItems, each of which have a Selected property.

C Sharp:

public static IEnumerable<ListItem> GetSelectedItems(this ListControl checkBoxList)
{
    return from ListItem li in checkBoxList.Items where li.Selected select li;
}

Visual Basic:

<Extension()> _
Public Function GetSelectedItems(ByVal checkBoxList As ListControl) As IEnumerable(Of ListItem)
    Return From li As ListItem In checkBoxList.Items Where li.Selected
End Function

Then, just use like this in either language:

myCheckBoxList.GetSelectedItems()

Questions:
Answers:
string s= string.Empty

for (int i = 0; i < Chkboxlist.Items.Count; i++)

{

    if (Chkboxlist.Items[i].Selected)
    {
        s+= Chkboxlist.Items[i].Value + ";"; 
    }

}

Questions:
Answers:
List<string> values =new list<string>();
foreach(ListItem Item in ChkList.Item)
{
    if(Item.Selected)
    values.Add(item.Value);
}

Questions:
Answers:

This thread was by far the best with many good examples!

One thing that i ran in to was neither of the examples worked for me and i spent hours of debugging, i could for all the reasons in the world not understand why i dident managed to get the selected values from my checkbox list.
Was it becasue of my master page? Or because i was using a ModalPopup with AjaxControlkit or was I going the right way when creating my checkboxlist from a database query?

I finally realized that i’ve missed an important part in all of this…

In my codebehind i created a checkboxlist from sql db in my Page_Load event and in my button_click event did all the get values from checkboxlist etc.

So when i checked some checkboxes and then clicked my button the first thing that happend was that my page_load event recreated the checkboxlist thus not having any boxes checked when it ran my get checkbox values…
I’ve missed to add in the page_load event the if (!this.IsPostBack)

I hope that my misstake and this answer can help minimize some debugging hours for some out there.

protected void Page_Load(object sender, EventArgs e)
{
   if (!this.IsPostBack)
   {
      // db query and create checkboxlist and other
      SqlConnection dbConn = new SqlConnection(WebConfigurationManager.ConnectionStrings["ConnString"].ConnectionString);
      string query;
      try
      {
        query = "SELECT [name], [mail] FROM [users]";
        dbConn.Open();
        SqlDataAdapter da = new SqlDataAdapter(query, dbConn);
        DataSet ds = new DataSet();
        da.Fill(ds);
        if (ds.Tables[0].Rows.Count != 0)
        {
          checkboxlist1.DataSource = ds;
          checkboxlist1.DataTextField = "name";
          checkboxlist1.DataValueField = "mail";
          checkboxlist1.DataBind();
        }
        else
        {
          Response.Write("No Results found");
        }
       }
       catch (Exception ex)
       {
          Response.Write("<br>" + ex);
       }
       finally
       {
          dbConn.Close();
       }
   }
}

protected void btnSend_Click(object sender, EventArgs e)
 {
   string strChkBox = string.Empty;
   foreach (ListItem li in checkboxlist1.Value)
    {
      if (li.Selected == true)
       {
         strChkBox += li.Value + "; ";    
         // use only   strChkBox += li + ", ";   if you want the name of each checkbox checked rather then it's value.
       }
    }
   Response.Write(strChkBox);
 }

And the output was as expected, a semicolon separeted list for me to use in a mailsend function:

    [email protected]; [email protected]; [email protected]

A long answer to a small problem. Please note that i’m far from an expert at this and know that there are better solutions then this but it might help out for some.