Web Forms :: How To Load The DropDownList Controls With Items Before The Form Databinding Occurs
Oct 11, 2010
I have a webForm which host a gridview and a formview. The formview is used for showing/editing a record which the user Select from the gridview.
In the formview Edit template I used DropDownList controls with
SelectedValue='<% bind("datafield")%>'
for enabling the user easier interface. A few of the DropDownList controls need to have a list of 100 items and I want to load the items from code behind and not from the aspx.
I tried to update the DDL's from FormView.Load, FormView.ModeChanging, FormView.PreRender but
nothing I am getting an error like this:
[code]....
How do I load the DropDownList controls with items BEFORE the form databinding occurs.
I have a formview that has several dropdownlists in the EditItemTemplate. Some of the dropdownlists are added using placeholders. I can add and populate their listitems without any problem. But when I update the record, none of the controls can be found--even though when I look at the page source they are there. I first strated out using asp:ControlParameter in my sqldatasource updateparameters, but even referencing the control as myform$mycontrol did nothing. So then I moved to code behind on the sqldatasource.updating event (code is attached). The only controls I cannot seem to bind to the update are those added via the placeholder.
[Code]....
The item at the dim statement is not an item added using a placeholder and does not get a null reference exception (I used that to prove during debbugging that I wasn't losing my mind)--however, all the items being used to get the parameter values are getting null reference exceptions and are added via placeholders. Here is the code I'm using to set up the dropdownlists:
[Code]....
how to get the value of these controls so they can be used in my update?
I'm using a code-behind function (called TestFx) in my binding expression. I'm passing a string and the function accepts a string but I still get a runtime error saying invalid args.
But if I change the method to accept an object and inspect the value, "it's a string!"
I have a gridview in which I have two drop downs. One is populated with values that are static, so I have a regular sub that does that in the code behind. I tried to add code for databinding the other ddl to a datatable. I cannot get this to work. It just comes up empty. My asp code is fine, and the datatable definately has data in it - just nothing gets populated.
One other thing - the code for the static ddl has worked fine, but when I add this other block (either to the same sub as that, or dow the rowdatabound event) the static one doesn't work either.
I am trying to create a Gridview in which I can update the Project Officer name in the Gridview from a DropDownList.
The Project Officer DDL comes from a seperate query (SqlProjectOfficerName) as the other information (SqlDataSource1)... as you can see below.
When I select EDIT, the DDL appears and I can select from the list of Project Officers, but when I select UPDATE, the name of the Project Officer doesnot change.
review the code below and assist as appropriate to write the Project Officer's name back to the table.
I have many controls on my form, but in particular, I have 2 dropdownlists. 1 dropdown list has 2 values, and each value controls what the second dropdownlist displays. This is an edititemtemplate and both dropdowns have the selecteditem set via '<%# Bind("fieldname") #>' on page load.
THe problem is, if I change the value of the first dropdown, it errors out because the second dropdwon has a bound value that is no longer acceptable.
Can I cancel the bind of the second control, if the the first one is changed? I would like to cancel the bind, and update the values by using a different datasource depending on the value of the first dropdown or hardcode the new values.
If Dropdown1 has a value of "A" for example Dropdown 2 Shows Values "1", "2", "3"
If Dropdown 1 has a value of "B" , Dropdown2 Shows Values "4", "5", "6".
It binds fine initially, but if I change Dropdown1 from A to B, I want Dropdown2 to show the new values, maybe with a default of "Select an Item" and not error out b/c it's attempts to bind a value of 1, 2, or 3.
Bringing back to life an old post that I dont believe ever got solved: http://forums.asp.net/t/1562245.aspxThis may be an old thread .... but no answer was ever given ... and I too have a radio button list and DDL and am stuck in the EXACT same place. If I check one of the two data bound radio buttons, the DDL should repopulate with a different set of results. This works just fine EXCEPT .... the DDL cannot be databound. If I set SELECTEDVALUE of the control to a bind I get this error:Databinding methods such as Eval(), XPath(), and Bind() can only be used in the context of a databound control.I have followed the advice on this page from various users, all to no avail....surely this can be done, and I assume quite simply. Anyone know the answer?
i have 10 list boxes in my aspx page for all 10 list boxes same function is using for some buttons i want to add listbox data to grid can you java script code shown below
f[code]....
i tried a javascript above code to move items between listbox using html input button problem when i trying to save listbox.items.count giving 0 can anyone tell me why this happening and also when post back occurs listbox items lost.
i have a webform which has got required field validators. when the user doesnt enter values and clicks submit button it should not cause postback. i have set CausesValidation="True" on the submit button.hen the user clicks submit button without entering values, validation occurs( red * marks are shown) but the postback also occurs.
I'm new to asp.net. I have a page with formview to read, edit and insert data to sql server 2008. On the page there are textboxes, dropdownlists. The Dropdownlist1 is bound to a lookup table. I also have a pop-up page to add, delete and update data underlying table. The problem is after i insert a new record to the lookup table and close the pop-up page, rebind the dropdownlist on the parent page. I'm refreshing the page with window.opener.location.href ....
but i want only the refresh the dropdownlist on the parent page.
When designing an ASP.NET user control my standard way for creating say a details view would be to create a property of the desired type on my page and would set the property in the page load based on the supplied query parameter. I feel I'm probably doing more work then necessary. If I could encase my view inside a container then I could merely have it databound and thus make everything declarative.My question is what would be the lightweight container/controls that would be appropriate for databinding a single object?As a second question, how can I handle invalid query strings with this method?
I've got a class that implements IListSource and returns a generic List of ListItem objects (List<ListItem>). in this list one of the ListItems has the Selected attribute set to true.On the web page I have a standard asp:dropdownlist and I set it's datasource to the getList method of my class and databind it.The problem is that the databind seems to loose the selected Item and the first item in the generic list becomes selected.
I have a DropDownList with a list of orders. When an order is selected from the list I generate a GridView with details of that order. Within the GridView I call other databound controls and all works fine until I finish the orders in the DropDownList
I have tried to enclose the code within a if dropdownlist.items isnot nothing end if but it makes no difference
This is the code:
Protected Sub GridView1_DataBound(ByVal sender As Object, ByVal e As System.EventArgs) Handles GridView1.DataBound If DropDownList1.Items IsNot Nothing Then GridView1.SelectedIndex = 0 [code]...
I am using C# ASP .NET 2.0. I have a web form with two DropDownList controls. In my code behind I get data from a DataSet. One column is a string (Month), and another is an integer (StatusID). I am setting the selected item in the each DDL in the code behind by doing this:
[Code]....
I have a button with a Click event. What I want to do in the click event is be able to check if the currently selected item in each DDL (if the end-user changed the selection) is different from what was selected in the above code.
i have dropdownlist. After i loaded data from javascript to dropdownlist,i used dropdownlist.item.count but counter always null. how to refresh dropdownlist?
In my project I have a listview which I am binding from code behind. Now I would like to add a droppdownlist for each item in listview. So my question would be:
Is there a way to populate my dropdownlist whit data which I have in a List?
Here is a bit of code to show how my listview looks like:
I am placing a dropdown list in the footer of a DataGrid like this:
[Code]....
In my code behind file, in the myDDL_OnLoad event handler, I call to the database, populate a SqlDataReader, and set the DDL's datasource to that datareader. I define what data columns should be used for the DataValueField and DataTextField of the dropdownlist. Then I call the DropDownList's DataBind() method. Everything works without error. But, when the dropdownlist is displayed, it has blank lines in it.
By that, I mean if 8 records are loaded into the dropdownlist, it will expand to a size appropriate for 8 rows but, it will be empty. there is no text in it.
Has anyone seen this type of behavior before? This dropdownlist is in the footer of a dynamically loaded ajax update panel so, it is difficult to see the source code to see what values are in the html element rendered to represent the dropdown.
environment: VS2008 When running below code the DDLKlient.DataBind() appends the whole set of names to the already existing list. I.e. I have 2 sets of names in the DropDownList!Question:? what can I do to prevent appending and just get 1 (one) set of names?? is there any refresh option?
Protected Sub DVKlient_ItemInserted(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.DetailsViewInsertedEventArgs) Handles DVKlient.ItemInserted Dim connString As String
