Web Forms :: Dropdownlist Selection Changes To First Item On Postback
Oct 19, 2010
I have been having some trouble with dropdown lists reverting back to selecting the initial item in the list after a postback once a selection has been made from the dropdown list. I have read up on this and found out that a "if not ispostback then" is required.This works fine when I add in all the items in the dropdown list manually like:
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Not IsPostBack Then
ddl1.Items.Add("Select...") [code]....
However, I have over 250 items and so it is far more efficient for me to load then in by using part of a multidimensional array which is created from a text file - Definitive database.txt. I have been using the following code to do so:
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Not IsPostBack Then
'loads the definitive database array[code]...
This loads all the items into the dropdown list perfectly, but now every time a selection is made, it reverts back to the inital item on postback even though i have included the "if not ispostback then" part.
In Internet Explorer, if I scroll down (say to United States) and then click it, the list scrolls back to the top. United States is still selected, if I press the "Assign" button it will appear within the second list box, and if I scroll down I can see that United States is still selected.
However, users are complaining about this, especially since it happens so quickly that they can't select multiple countries.
I tried using smartnavigation and MaintainScrollPosition, but this has had no effect.
I have a dropdown list which has states retrieved from a table. I want to have an option to add new states.. I have added a list item NEW in the dropdown. When I click on NEW i should get a pop up to add a new state and goes in the table.
I have a search page with a TextBox that allows someone to type in a search term and press enter. (Which fires TextChanged). I have a DropDownList that specifies the kind of search that will be performed. It is defined in the markup as follows:
As you can see, AutoPostBack is set to false, and there is no event hookup.
Pressing enter fires the OnTextChanged event for the TextBox, which performs a search and updates a GridView in an UpdatePanel. This UpdatePanel has its UpdateMode set to conditional and has one trigger: the TextChanged event of the search TextBox.
It's very simple.
And it works beautifully, almost.
Whenever I change the search type, the very next search does a full postback. All subsequent searches do partial postbacks (as desired) unless I change the search type again.
There is one exception to this rule: if I load the page and immediately change the search type, it doesn't do a full postback. So the first change of the DropDownList before any postback (full or partial) does not trigger a full postback.
Full Disclosure: I'm doing a lot of JavaScript to change the appearance of the gridview during async requests. I don't detail it here because it seems unrelated. This problem only occurs when a DropDownList with no JavaScript wired up is changed.
I'm trying to put a updateprogress into a webpage where selection from the dropdownlist causes postback. Works out well except that on the first postback, the gif image shows on the leftside rather than on the center. On succeeding postback, it will show on the centre where I intend it to be. Below is my code:
I have two dropdownlists on my page that are related to one another, and are built dynamically. I did not write the original code, but I believe it is using AJAX so the whole page doesn't postback when the ddl selection changes. The first ddl is Status and the second is ContractType. Here is the code for the event handler:
I commented out the event handler since this snapshot, just to see what would happen, but when I was hitting it you can see what ex.Message was. I don't understand why it says the SelectedValue is invalid when I see the selected value is "E " and that is one of the four items in the ddl.
I have 2 dropdownlist controls (ddl1 and ddl2). When I pick an item from ddl1, it will update ddl2. The problem is when I pick an item in ddl2, it always selects the first item in the list. Is it that the ddl2 autopostback causes the first ddl1 to reload and results the ddl2 to be refreshed also? Or I didn't set something correctly?
i have a gridview which consists of databounds and dropdownlist control. When I press the Add Grid Row Button, it will insert a row. Now my question is, if the user selected an item in dropdownList in the firstrow and the user click the AddGridRowBtn Again which will generate the 2nd row, how would i maintain the selectedItem in the dropdownlist after postback?
I have a ASP DropDownList that gets populated on the Page_Load event, after i select an item and hit a button the selected item gets cleared and the first item in the DropDownList gets selected. (The DropDownList is only populated when the page is not postback)
if (!IsPostBack) { List<Country> lCountries = new List<Country>(); List<CompanySchedule> lCompanySchedules = new List<CompanySchedule>(); this.Load_Countries(lCountries); [code]...
Wat i did is in the first header of gridview dropdownlist i have binded the PO Item , so that user can select item n make invoice...
Here the problem is user will click addnewrow button to create new row second row , again user is able to select the same item what he selected in first row of gridview. here how to avoid duplication in the second row .
Say i have four PO item
Item1,Item2,Item3,item4
user may select Item1 in first row , after clicking addnewrow button user will get second row
here again user is able to select Item1 from dropdownlist ... how to avoid duplicate selection
coz the dropdownlist is binded from database using sqldatasource n filter based on user selected PO no.
Duplicate Item selection should be removed until all the four item is selected ...
all elements are in an updatepanel. click on a list of <tr> to fire a JavaScript function to add new <option> to the asp dropdownlist. But, when I click on other buttons to callback to the server, I get an error message:
Uncaught Sys.WebForms.PageRequestManagerServerErrorException: Sys.WebForms.PageRequestManagerServerErrorException: Invalid postback or callback argument. Event validation is enabled using
in configuration or <%@ Page EnableEventValidation="true" %> in a page. For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected, use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation. I understand the problem. I need to let server side know the change of the dropdownlist before any other postback. Set validation as false won't work in this case, the dropdown will lose the new item anyway. I did some researches, and the possible solutions:
1)Using ViewState? Request Form? could anyone give an example?
2)Add dropdownlist item in server side. But I want to make the whole tr row clickable to fire the event. Could I click on tr and fire eg. its first child linkbutton or a linkbutton in somewhere else.
3)I've tried Jquery.ajax and webmethod , it can fire server event but since all method are static (shared) , it doesn't allow me to edit the downdownlist instance.
I have a dropdown populated with data , based on a true / false condition i change the dropdown item color when dropdown gets loaded initially the item color are proper based on condition. but if i select a particular item & then again click on dropdown the item color disappear show to retain the item color.
Here when i click on button it insert all data into table but it didn't insert my selected item from dropdownlist it insert select city that i define in page_load
DDL1.Items.Insert(0, new ListItem("select city", "0"));
And when i delete this code from page load it insert in table first row of my table it didn't insert my selected item from dropdown list.
What I need is if I select default item i.e. 0 in Zone dropdown I need to show all items in store dropdown. Below is my stored procedure to get the stores
ALTER procedure [dbo].[selectcenter] @RegionID varchar(5) as begin select ID,Centername from Shoppingcenter where RegionID=@RegionID group by ID,Centername end
I have 2 dropdownlist, one is to dropdown department, and another dropdown staffnames. the secong dropdownlist will based on the selection of department as each department has different staffs i have 2 tables department and staff in my database , in my department table i have departmentid as PK and departmentname, in my staff table i have staffname and departmentid as FK. So my ques is how am i going to populate staffname in the dropdownlist according to the selection of department.
I have one table which contains branch codes(primary key), Branch name and bank name columns. I have 3 dropdownlist boxes. the first dropdownlist is for the branch codes. When i select the a branch code i need the second dropdownlist box to populate with the appropriate branch name and the third dropdownlist box to populate the bank name at the same time.
Is it possible to have one table like mine and acheive this, if so how do i go about doing this?
I did read up on this but only came across ones with 3 tables.
I need to add an item in a dropdownlist and also modify the value of that item, but im getting an error : "Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index"here's my Page load
Dim rt as new OleDbCommand("Select * from Question ", con) dim rd as OleDbDataReader rd = rt.ExecuteReader Dim a as new OleDbCommand("Select Count (*) as C from Question" , con) [code]...
I am having two dropdownlist in my project,one dropdownlist for empid, another dropdownlist for month, if the user select the empid, the values are retrieved in the textbox.
In the second dropdownlist, if the user select the month in the dropdownlist it will display the leave details, its all working fine, if the user again select the first dropdownlist that means empid, I want to show the second dropdownlist as select month, how can do this.....
Is there a way that we can change the color (which is defaulted to blue) when the items in the list box are selected? If so can you provide me a sample for it?
I have a dropdownlist on my page with dates such as 1/1/2013, 2/1/2013, etc.
Then there is a second ddl.
If the date in ddl #1 is before 1/10/2013 I want to enable ddl #2. If the date in ddl #1 is on or after 1/10/2013 I want to either disable ddl #2 or hide it (whichever's easier).
Disabling ddl #2 based on the selected date is a new requirement so I am enhancing the existing code. Obviously I want to do this without a postback, but I don't know what is the best way. I am trying to understand what an AsyncPostBackTrigger is because this is the existing code:
I have a project that queries a set of times from a database and uses these entries to populate a dropdownlist. Once the page is loaded, the user can select one of the items in the DropDownList. When the "Save" button is clicked, the Selected item value is returned to the [HttpPost] version of the controller action. This item is then stored into session. If the system returns to the page containing the dropdown, I want the saved Value to be selected in the DropDownList. What actually happens is that the DropDownList is always set to be the first item in the list.
Database Table: This data has been imported using Link to SQL
I had use a combox to let user select staff name and then it will automatically retrive the responsible recommending officer and approving officer to display in other 2 dropdownlist.
my code works fine but when user select staff name each time, the page will reload once to refresh the dropdownlist.
user complaint and don't want the page reload every time, how can i disable the postback? I need to use ajax?
