How to get the selected-row count from a list box in asp.net

in开发者_运维知识库t countSelected = ListBoxMembers.Items.Cast<ListItem>().Where(i => i.Selected).Count();
       string groupName = txt_GroupName.Text;


       for (int counter = 0; counter < ListBoxMembers.Items.Count; counter++)

I have 20 items in the list, when I select only 2 ListBoxMembers.Items.Count shouws 20 and Countselected is 0

i tried this int count = ListBoxMembers.GetSelectedIndices().length; system.web.ui.controls.listbox does not contain a definition for selected items and no extension method selevted items acceptin first argument error

 <asp:ListBox ID="ListBoxMembers" runat="server" SelectionMode="Multiple" CssClass="style102"
                                   ToolTip="Press ctrl to select multiple users" DataValueField="FirstName"></asp:ListBox>

Just use the functionality built-in to the ListBox ... no Linq required. (For WinForms)

int countSelected = ListBoxMembers.SelectedItems.Count;

Edit: (since the OP added to the question and it appears it is regarding ASP.NET)

int countSelected = 0;
foreach(ListItem li in ListBoxMembers.Items)
    if(li.Selected)
        countSelected++;

I'm not sure why the Linq statement is not working. It certainly appears that it should be... is there any difference if you explicitly include true? i => i.Selected == true

Your code looks correct, but you can try this:

int count = ListBoxMembers.GetSelectedIndices().Length;

there should be somehting like listBoxMembers.SelectedItems which returns a list of the selected items. So you could do listBoxMembers.SelectedItems.count. Now this is in VB.Net but there should be something like it for C#