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.
