Two things: First, the issue is probably with the shopping cart list because each item you are passing to it is selected. Given that this is probably only a reference to a control, changing it to be not selected might affect both lists. To get around this, I would try the following:
dim newItem as new ListItem(lstProducts.SelectedItem.Text, lstProducts.SelectedItem.Value) lstCart.Items.Add(newItem) Second, I would recommend that if you plan on using this in an actual site, you consider client side code to do the moving of items between lists. It will take a lot of round trips for someone to fill up your list the way you are doing it. HTH, Matt -----Original Message----- From: Kevin Burton To: [EMAIL PROTECTED] Sent: 5/30/02 9:17 AM Subject: Re: [DOTNET] ListBox error in ASP.NET I would like to simply deselect this but I am unsure as to where to do it. Here is there complete source. If I deselect the selected item on the 'SelectedIndexChanged' event then isn't it too late? Kevin <Script Runat="Server"> Sub lstProducts_SelectedIndexChanged( s As Object, e As EventArgs ) lstCart.Items.Add( lstProducts.SelectedItem ) End Sub Sub btnRemove_Click( s As Object, e As EventArgs ) lstCart.Items.Remove( lstCart.SelectedItem ) End Sub Sub btnRemoveAll_Click( s As Object, e As EventArgs ) lstCart.Items.Clear() End Sub </Script> <html> <head><title>ListItemCollection.aspx</title></head> <body> <form Runat="Server"> <h2>Products:</h2> <asp:ListBox id="lstProducts" Width="200" AutoPostBack="True" OnSelectedIndexChanged="lstProducts_SelectedIndexChanged" Runat="Server"> <asp:ListItem Text="Hair Dryer"/> <asp:ListItem Text="Shaving Cream"/> <asp:ListItem Text="Electric Comb"/> <asp:ListItem Text="Nail Polish"/> <asp:ListItem Text="French Toast"/> </asp:ListBox> <p> <h2>Shopping Cart:</h2> <asp:ListBox ID="lstCart" Width="200" Runat="Server"/> <br> <asp:Button id="btnRemove" Text="Remove Item" OnClick="btnRemove_Click" Runat="Server"/> <asp:Button id="btnRemoveAll" Text="Remove All" OnClick="btnRemoveAll_Click" Runat="Server"/> </form> </body> </html> -----Original Message----- From: Patten, Dave [mailto:[EMAIL PROTECTED]] Sent: Wednesday, May 29, 2002 6:24 PM To: [EMAIL PROTECTED] Subject: Re: [DOTNET] ListBox error in ASP.NET Can also: lbTemp.SelectedIndex = -1; or lbTemp.SelectedItem.Selected = false; Before selecting a new Item programmatically. Shouldn't have to walk the entire Collection. -----Original Message----- From: Matt Milner [mailto:[EMAIL PROTECTED]] Sent: Wednesday, May 29, 2002 3:51 PM To: [EMAIL PROTECTED] Subject: Re: [DOTNET] ListBox error in ASP.NET Either disable view state for the control or walk the collection of items and set "selected" to false for all but the one you want. The control is holding on to the selected setting from the last post and then you are probably setting another item to be selected. HTH, Matt Matt Milner BORN [EMAIL PROTECTED] -----Original Message----- From: Kevin Burton To: [EMAIL PROTECTED] Sent: 5/29/02 5:05 PM Subject: [DOTNET] ListBox error in ASP.NET I have a ListBox that I only want to have a single item selected at a time and when that item is selected I want it to be copied into another ListBox (this is an example in ASP.NET Unleashed p. 224 and 225). The first selection works just fine but the second selection gives me the following error. It seems that the error is getting thrown before the first selected item is unselected. Any ideas as to a work around? Kevin A ListBox cannot have multiple items selected when the SelectionMode is Single. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.Web.HttpException: A ListBox cannot have multiple items selected when the SelectionMode is Single. Source Error: An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. Stack Trace: [HttpException (0x80004005): A ListBox cannot have multiple items selected when the SelectionMode is Single.] System.Web.UI.WebControls.ListBox.RenderContents(HtmlTextWriter writer) +343 System.Web.UI.WebControls.WebControl.Render(HtmlTextWriter writer) +29 System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +243 System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +72 System.Web.UI.HtmlControls.HtmlForm.RenderChildren(HtmlTextWriter writer) +44 System.Web.UI.HtmlControls.HtmlForm.Render(HtmlTextWriter output) +397 System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +243 System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +72 System.Web.UI.Control.Render(HtmlTextWriter writer) +7 System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +243 System.Web.UI.Page.ProcessRequestMain() +1900 You can read messages from the DOTNET archive, unsubscribe from DOTNET, or subscribe to other DevelopMentor lists at http://discuss.develop.com. You can read messages from the DOTNET archive, unsubscribe from DOTNET, or subscribe to other DevelopMentor lists at http://discuss.develop.com. You can read messages from the DOTNET archive, unsubscribe from DOTNET, or subscribe to other DevelopMentor lists at http://discuss.develop.com. You can read messages from the DOTNET archive, unsubscribe from DOTNET, or subscribe to other DevelopMentor lists at http://discuss.develop.com. You can read messages from the DOTNET archive, unsubscribe from DOTNET, or subscribe to other DevelopMentor lists at http://discuss.develop.com.
