DataBind Of DropDownList Works But Does Not Show In Code Behind
Mar 17, 2011
I'm working on web pages that have an ASP DropDownList defined, and on page load the data source is bound to it through DataSource.DataBind(). When I step through the code, the drop down list does not show anything in it, but when the page actually displays, it does have items in the list. When exactly does DataBind() get applied to the control?
The problem is that some of the values returned by the SQL back end have a null Text, so nothing is displayed in the drop down list for that row. I want to just use the Value as the Text, but only if the Text is null. And when I put the code to loop through and do that right after the DataBind(), there is nothing in the drop down list at that point in the code.
i'm opening a new window and passing on to it variables in a querystring, the values are loaded into a function that is filling my dataset and then filling my Gridview. after i press the button field in my grid to delete an item, the databind doesn't show the updated grid but remains the same. i've noticed that if i navigate back and refresh i see it correctly. in FF btw no problem.
i have a gridview that binds data after changes were made (delete,update..) and it's all done with the c# method DataBind() and i don't know why FF shows the changes but in IE8 the grid remains the same and only if i navigate back and refresh, then i see the changes.
I m not able to understand what is datavaluefiled and datatextfield are doing here ...... why i can't bind dropdownlist without these two property and what is is use ?Please provide me link if possible .. I m not able to find the correct keyword for searching
I have a DropDownList in my page, it DataBind with a objectDataSource.
when user select an option base that i have a FormView that show the detail of selected option an it also work with an othere ObjectDataSource.
when user insert, delete or edit an option for example the name of option will in edit mode changed and i need the DropDownList be refresh that show the new name of option.
i alredy know where should i write the code but i don't know how to refresh the DropDownList without dataBind the DropDownList because AppendDataBoundItems="True".
Object reference not set to an instance of an object. 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.NullReferenceException: Object reference not set to an instance of an object. Source Error:
Line 22: ((GridView)LoginView1.FindControl("GridView1")).DataSource = query;
How to show GridView inside Login with databind in c#?
Assuming i have two dropdownlists namely: dropdownlistA and dropdownlistB. at page load, i bind values to dropdownlistA. however, depending on the value selected or displayed in dropdownlistA, i want to bind data to dropdownlistB.
Currently, i can bind data to dropdownlistA alright and i already have the required dataset and datatable bind data to dropdownlist. However, dropdownlistB does not bind at page load since the criteria for filling the dataset to bind dropdownlistB (which is the value of dropdownlistA) is not selected. how can i make this wwork.
I am currently considered if this might work. If i were to call the databind for dropdownlistA in a different declared method besides its binding in page load, and select the value from bind in the declared method, would any value be selected?
For example:
In during page load, i call the a method that returns dataset values which i bind to dropdownlistA(caseIDDropDownList). then i call another method (CreateexhibitDataSet()) which contains the dataset values for binding dropdownlistB(exhibitDropDownList). however, i need to define a criteria in the CreateExhibitDataset() method which i will use to generate the dataset values to bind dropdownlistB. if i were to call for the data bind of dropdownlistA(caseIDDropdownList) again in the CreateExhibitDataset() method and pick the value in the dropdown list, would i get any values?
How can i work around this to bind both dropdownlists on page load?
This is my setup: I've got a dropdownlist of people and a linkbutton next to it to add a person. the linkbutton makes an update panel appear. When clicking save, I want the data to be saved and the new person be selected in the dropdown. As far as I can tell, I have done this properly. After I save the data I refresh the dropdownlist and take the new person's value and set it as the selected value. When stepping through, it shows the ddl with the new person and the new person selected! BUT, when the page comes back, the ddl is unchanged, ie NOT refreshed. I thought it might be something with the Update Panel but I got a similar setup to work on another page! It also works on a nested Update Panel (not shown in the following code). Can you think of why this "deception" is happening?
[Category("Settings")] public int ClientID { get { return Int32.Parse(DropDownList1.SelectedItem.Value); } set { DropDownList1.Items.FindByValue(value).Selected = true; } }
Getter commonly is being called by ControlPameters in SqlDataSources on pages with this control.
Setter - from markup: <uc:UserControl1 runat="server" ClientID='<%# Bind("ID") %>' />.
Why does setter from Bind is called earlier then PreRender? And DropDownList is empty and item selecting doesn't work! How to workaround this behavior?
On my test machine (Windows XP with IIS 5), I set up a virtual directory just for this ASP.NET 2.0 solution and everything works great. All my code is separated nicely and it just works.However, when we deployed this solution to our Windows Server 2003 development environment, we noticed that the code only compiled when all of the code was dropped directly into the .asmx file, meaning that the solution didn't work with code-behind. We can't figure out why this is happening.
One thing that's different about our setup in our development environment is that instead of creating a separate virual directory just for this solution, we dropped it into an existing directory that runs a classic ASP application. So here we have a folder with an ASP.NET 2.0 application within a directory that contains a classic ASP application. Granted, everything in the ASP.NET 2.0 application works if all of the code is within the .asmx file and not in code-behind, but we'd really like to know why it's not recognizing the code-behind files and compiling it correctly.
I want to create this scenario: The user selects a school from ddlSchool and this populates ddlStaff with a list of staffs in that school. i knw the codes for sql database but dont know how to do it for oracle.
I would rather not magic string my DataTextField/Values on the dropdownlist after setting up the source as a List collection of objects.
I was thinking I could use the DataSource properties but it doesn't seem to like the couple of ways I tried.
WORKS BUT NOT IDEAL //set the datasource to the returned List<Cart> this.cartDdl.DataSource = CartManager.Load(WebProfile.Current.UserName); //set the DataValueField to the Cart.ID property this.cartDdl.DataValueField = "ID";//would rather use the obj property Cart.ID //set the DataTextField to the Cart.Description property this.cartDdl.DataTextField = "Description";//would rather use the obj property Cart.Description //Bind the ddl to the datasource this.cartDdl.DataBind(); HOW I WOULD THINK IT COULD WORK this.cartDdl.DataValueField = ((Cart)this.cartDdl.DataSourceObject).ID; this.cartDdl.DataTextField = ((Cart)this.cartDdl.DataSourceObject).Description;
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
I am not sure if I'm in the right forum but I try anyway.I am making a webproject where I have a database with tables Product, ProductDetails.In my pageLoad event I am retrieving the information from these tabels in two lists: productList and productDetailsList.
Now what I would like to do is to databind these lists in code behind to my ListView. I know how to do this if I only have one list but in my case i have two and in my listView i have fields whose information is in productList list and others in the productDetails list.
Is there a way to achieve this?
Here is some code where I am databinding one List to ListView:
I wanted to disable a button after it is clicked and at the same time fire the post back event to generate a report. My first set of code did not work because soon after the button is disabled the page won't submit/post back. here's the first set of code which was not implemented. the onclientclick calls a javascript function which has these lines
its not working from client side alone after I disable the code behind attributes.add but when I check the view source the 2 pages are the samewhy am I not able to move the code from code-behind to design view?
I have a textbox, with a RequiredFieldValidator and a ValidatorCalloutExtender. The calloutExtender comes up when there is no text in the textbox, but it does not display the error message from the RequiredFieldValidator. I tested this code in a test app, and it worked. It may have something to do with the content containers? These controls are inside of a web user control, which are inside a Telerik RadDock. The parent page also uses a MasterPage. Here is my code from the usercontrol which contains the validator:
I placed 2 requiredfieldvalidators in my page (well, actually, more like a dozen of them, but only these 2 behave this way) and can not seem to figure out why the error message will not be displayed. The validation function works (the processing code is not run and focus is returned to the first field that fails validation) but no error message.
In a website I'm working on, there is a link to ~/Products/1/2%20Inch%20Tube.aspx (1/2 Inch Tube.aspx). As I'm using a fake path the name of the URL is not a problem appart from the fact that there is a slash in the name. The URL safe code for it is %2F, and I use a replace to check for this in my SQL query (REPLACE(ProductName, '/','%2F')) AS Link, and before that in the eval statement (NavigateURL='<%# "~/Products/" & Eval("Link").ToString.Replace('/','%2F') %>'). Sadly when databinding this using an eval to a Hyperlink, the %2F changes back to a / (Slash)
Is there a work around for this or should I just not allow for slashes when saving products.
I'm using what I believe is a pretty common/boring/generic implementation of a ModalPopupExtender. I'm using client-side JS to show the dialog when the user clicks a link, and hide it if they click "cancel". I only do a postback if they truly want to save the data.
I can click the link to show the dialog, then click the cancel button to hide it, then click the link to show it... ad infinitum. If I decide to save the data via a postback, everything works well, and the dialog is hidden as a result of the postback, all as expected.
However, once the postback completes, my client-side JS show() never works again. Any attempts to click the link fail quietly; no error messages, the dialog just never shows again.
Please look at this method that looks intuitive but not working, I want to use a one parameter search method when search word is not empty and the parameterless method when it is empty I wrote these two methods that are not working because select parameter doesn't added or removed in the selecting method:
[Code]....
[Code]....
[Code]....
why this code works but the previous one not? I'm very disappointed to see this because based on what I learned the first one could also work.
