C# - Binding DropDownList's SelectedIndex To 0 If Value Does Not Exist?
Mar 17, 2011
I have a DropDownList in a DetailsView, which binds a user's 'AllocatedUser' to a user in the Users table. Occasionally, we'll have some mishaps in the database where the user allocated isn't in the users table, which the DropDownList is filled with. In this case the site crashes and we get a 'SelectedValue does not exist in the list of items error'.What I want to do is catch any binding errors like that, and just set the DropDownList index to 0. I've tried something like this:
I'm having trouble binding my textbox to my dropdownlist. I got it to work but I don't think it is the correct way of doing it. I have my DDL bound to a datasource and populating everything correctly. However, I couldn't find a better way of binding my textbox to it besides using the FormView control and its counterpart, Templates (edit,insert,etc) It looks messy and i was hoping there was a better way of doing it. I've researched it online for awhile now but I couldn't understand how to implement for my situation.
My DDL has company names in it and the datasource has all the information from the table including what I'm trying to have my textbox pull (Address).
Is this possible? I programatically change the selected index when a certain event is fired using this code:DropDownList.SelectedIndex = DropDownList.SelectedIndex + 1ow I want to update a corresponding textbox with the text that is in the new SelectedIndex of the DropDownList via postback.I know how I can do this in javascript
I have 3 security question drop down menus. I have javascript on the ASPX page that removes questions/repopulates them when you select a questions (so you cannot reselect the questions in the other 2 boxes). This works wonderfully when a user is editing their profile with already selected questions. However, when a user first selects the questions where all three boxes are listing "select a question" at selectedIndex 0, the onChange doesn't fire. The function won't even go. I think this has a big something to do with the on change from selected index of 0. I have debugged this thing and it doesn't even enter the function. I even set the onchange action to flash an alert. It just seems something is going wrong when i try to action onchange from selected index of 0.
I have a dropdownlist, who's items I bind from the codebehind file of an asp.net web page. After databinding, I want to set the selected index as the last item in the list, thus:
[Code]....
However, this does not work. When the page is done loading, the selected index is still zero.
I have a repeater with a DropDownList in it. I set the datasource of this list in the itembound event en set the selectedindex. When I debug the selectedindex is set, but when the page is done loading for all the item the default item is selected.
I wanted to create a dropdownlist that would trigger an asynchronous postback and update the Gridview inside the Updatepanel. However, no matter what I do, when the dropdownlist changes, nothing in the UpdatePanel will change, even the TestLabel....I've been banging my head against the walls for days on this -- why won't this work? When I remove the UpdatePanel code and triggers, all the code works, eg, you change the dropdownlist andthen gridview updates -- but it refreshes the page and this is why I wanted to put the Gridview inside an Updatepanel to make it look cleaner.[Code]....
I have a datalist where each item consists of a textbox and a dropdownlist. I want to get the datakey value when a selected dropdownlist item changes. I can get the selected value of the dropdownlist, but I can't figure out how to get the key field value of the datalist row item that the dropdown resides in.
i can populate cascading dropdownlist by using webservice now. but may i know how do i trigger function while selectedindex changed? (without using auto postback...)
I'm trying to do a similar thing -- I have a long form and in part of it, I have an updatepanel.
Inside the updatepanel I have:5 dropdowns (using the CascadingDropdown functionality)One AddProduct ButtonGrid or Repeater (haven't set it up yet)
I want the following to happen:I have the AddProduct Button disabled initially, but I want it to be enabled once the 5th dropdown is selected (so OnSelectedIndexChanged).If they click the AddProduct button, I want it to populate a Grid or Repeater.So far I am just trying to show what the selection was in a label... but nothing happens. I have an OnSelectedIndexChanged function for the last dropdown, so it enables the button, but that doesn't appear to get called. Previously, before disabling the button, I tried updating the label on button click -- and nothing there either.
It just seems like, because they are in the updatepanel, those callbacks never happen. I also do have UpdateMode = Conditional and I have both items in the triggers list.
I am trying to use Yes No Confirmation Message Box but the code below here which i found here uses a button to raise the confirmation message box but what i would like to use is a DropDown. How can i modify the code and i use drop-down box instead of using a button? here is the javascript code:
<script type = "text/javascript"> function Confirm() { var confirm_value = document.createElement("INPUT"); confirm_value.type = "hidden"; confirm_value.name = "confirm_value";
[code]....
but here is what i would like to use is drop-down instead of the button:
I am using a dropdownlist in my application and it has corresponding SelectedIndexChanged() event.I would like to invoke GridViewEdit Event when SelectedIndexChanged event fires from dropdown list.Is it possible to implement this...??
<asp:DropDownList ID="ddlStatus" Visible="true" AutoPostBack="true" OnSelectedIndexChanged="ddlStatus_SelectedIndexChanged" runat="server"> </asp:DropDownList> protected void ddlStatus_SelectedIndexChanged(object sender, EventArgs e) { //Code to fire the GridViewEdit Event to put a row in edit mode }
I'm trying to load a gridview based on selection from dropdownlist. When i run the program, it displays empty gridview. How to solve this?
Name of dropdownlist: CatCode
Code behind:
Private Sub BindProdGrid() Dim conString As String = ConfigurationManager.ConnectionStrings("SY_InventoryConnectionString").ConnectionString Dim rowIndex As Integer = 0 Dim box11 As DropDownList = CType(SalesGView.Rows(rowIndex).Cells(1).FindControl("CatCode"), DropDownList)
I have had some issues with processing null values stored in a SQL Server database table that needed to be represented in a DropDownList. Inevitably if the value wasn't there [meaning that any value in the database must match one of the values in the DropDownList otherwise] you would get the following error:
'DropDownList' has a SelectedValue which is invalid because it does not exist in the list of items
My earlier solution to this problem was to not allow null values resulting in making sure that all fields had default values, and that all DropDownList boxes were equipped with and entry called "Select this" or some such nonsense. Of course this value would also be the default value in said field, which even I would have to admit, looked quite stupid. Enter my co-worker and classic ASP guy who insists that null values are OK in a database (I tend to come from the "No Null values allowed camp.") One look at my code, which looked like this:
when i change page from page1 to page 2 I remember Dropdownlist in session
Session("Dropdownlist")=Dropdownlist
now when i go back to page1 I set the Dropdowlist the way what it was before i left page1
Dropdownlist=Session("Dropdownlist")
Everything its remember but when i load the page with my Dropdownlist again. The selectedindex shows default value in the control Dropdownlist.But it does remmeber old selectedindex.I got it wired with Gridwiew and gridwiew show Data by remmeber old selectedindex. Well generally I like to remember selectedindex when i go to a differente page and when i go back have it set in the control dropdownlist the way when i left the page
I have a page with some bound DropDownLists (DDLs) for a Call Logging system. The Calls are categorised on three levels for example:
Call: 3069, Category 1: Incident, Category 2: Microsoft Application, Category 3: Word would be used to organise calls for problems with Microsoft Word. On testing the system, I noticed that there was no handling for opening a call if the category had been deleted - say for reorganisation/systems no longer supported whatever. So I set about trying to make the program behave in the following manner:
Check category ID exists in DDL before bindingIt doesn't: set the displayed text of the DDL to Category Name + "(Deleted)"Disable the control to prevent user changingMove on to next control Seemed simple enough, however no matter which way I try and do it I always get the messase ddl_Cat1 has a SelectedValue which is invalid because it does not exist in the list of items. What's really puzzling me is that the exception doesn't seem to be being thrown in the code behind. I've gone through line by line from Page_Init and it never throws and exception. Just when the page loads this appears.
Does anyone know of a reason as to why this wouldn't work? (I've already tried setting the selected value to an existing item, adding a new list item with the value and setting DataSource property to Nothing - in all different combinations.)
I have a drop down list inside a formview control's edititemtemplate and itemtemplate. The dropdown list is not bound to a data source. I am hard-coding the listitems for the drop down list. The formview is bound to a datasource. All I want to do is set the selectedvalue of the dropdown to what is in the record from the database. But I keep getting the error.
<asp:formview .....> <edititemtemplate> .... //some other controls like textboxes that are correctly bound and display the value from the datasource <asp:dropdownlist ID=myddl runat=server cssclass=myclass selectedvalue='<%# eval("mychoice") %>'> <asp:listitem value='0'>I dont know</asp:listitem> <asp:listitem value='1'>Yes</asp:listitem> <asp:listitem value='2'>No</asp:listitem> </asp:dropdownlist .....//rest of the edititem controls that display correctly. </edititemtemplate>
Just for kicks, I added a textbox and set it's value to eval("mychoice") as well and it correctly prints 0,1 or 2. So, I know that there is no illegal value coming back from the datasource. It seems as something with the timing of events - when the listitems are getting bound to the ddl. The error I get is - "myddl has a selectedvalue which is invalid because it does not exist in the list of items".
