I have created a label and a dropdownlist. The label has the dropdownlist as associated id.
If I click on the label and then uses the mouse up or down the dropdownlist creates a postback for each click. This is quite anoying and doesn't happen if you click on the dropdownlist and uses key-up or key-down, or if you uses another browser than IE.
Is it possibel to fix this, so you can use key-up and key-down without causing a postback, and first on the enter-key creates the postback (as it does if you click on the dropdownlist and not label)?
Set DropDownList.AutoPostBack to false.
Set the AutoPostBack property to false.
See the documentation.
Related
I am creating an ASP.net application. I fill a ListBox control with items and I use the PreRender event of the Listbox to set its width according to the largest item in the control.
But after the ListBox is rendered, the first time I click an item in the ListBox the PreRender event fires and focus is removed from the ListBox (this event fires unnecessarily because the ListBox is already rendered). The second time I click on an item in ListBox the PreRender event doesnt fire and focus is maintained.
Is this behaviour normal? What could cause this behaviour?
The ListBox is filled on PageLoad if is not postback, with a default value.
The Listbox is filled on the TextChanged event of a TextBox (the TextBox is used for searching in a DB)
EDIT:
I commented out the PreRender event and the behaviour is not gone. Now I am thinking this may be caused by a PostBack from the TextBox when I remove the focus from it and select an item from the ListBox.
The evidence to this regard: I have a gif that is shown between the beginning and end of a request from the TextBox (loading indicator) and the gif is visible when I select an item from the ListBox for the first time after a render. The second time there is no problem.
Use the AutoPostBack property to specify whether an automatic postback to the server will occur when the TextBox control loses focus. Pressing the ENTER or the TAB key while in the TextBox control is the most common way to change focus.
I have found out why the behaviour I reported happens. Can I somehow make the TextBox not to postback on losing focus? It is aleady posting back on TextChanged and it is enough.
Use the AutoPostBack property to specify whether an automatic postback to the server will occur when the TextBox control loses focus. Pressing the ENTER or the TAB key while in the TextBox control is the most common way to change focus.
I have found out why the behaviour I reported happens. I will now search how to stop the autopostoback on losing focus.
Hi I'm having a really strange issue here. I have an ImageButton and Gridview, both of which I create on runtime. The Image button is a seperate control on the webform and is not linked in anyway to the Gridview. What I am trying to achieve is when the user completes the editing of a line in the GridView and clicks on the update row button, I perform a set of calculations on the input entered. If an error is found with the data entered, I then make visible the ImageButton which when clicked displays the error message. The function I am using to make visible or hide the Image button through
picCross.Style.Value = "display: none;"
and
picCross.Style.Value = "display: block;"
gets called on the Page.PreRender function. What I have discovered is that I am able to make changes to the ImageButton (changing the button's tooltip, setting its Style's value ) during a postback not fired by the GridView, such as when the user clicks on a button else where on the web form. If however I try making changes to the Imagebutton during the post back event of the GridView, such as when the user clicks on the edit row or update row button/link. The changes are not saved. What is even more strange is I do not have such an issue with labels. I can change the text of labels regardless on whether the change was made during the postback fired off by the Gridview control.
I have tried setting the ImageButton's EnableViewState to true and false but neither makes a difference. I have tried the same approach with panels and the same thing occurs, I can't change its properties during a postback caused by the gridview. My GridView has EnableViewState = True
P.S I'm binding the GridView on runtime too. Only my GridView's RowUpdating event fires. The RowUpdated event does not fire. I was hoping to try changing the ImageButton on RowUpdated, not that I think it would have made much of a difference anyway.
You should create the dynamic controls (Gridview and ImageButtons) in the PreInit event. Init event if you have a Master Page.
Respected sirs
I am using a DropDownList control and binding it to a LinqDataSource.
According to the selection of the mentioned DropDownList, I need to bind another DropDownList control.
I have handled the SelectedIndexChanged event for first DropDownList. When this SelectedIndexChanged occurs, page is getting refreshed. To prevent page from beend refreshed, I am using an UpdatePanel control. But, still the second DropDownList not loading.
Please give me a solution.
Thanks
Saravanaa
Place the second DropDownList inside the UpdatePanel.
You may want to consider using CascadeDropDown too.
Am I doing this correctly?
I have two dropdowns. The first is populated on form load, and it is a trigger for an updatepanel that contains the 2nd dropdown.
When I change the value in the first dropdown box, it triggers the 2nd one's updatepanel, which populates it.
However, when I select a value in the 2nd dropdownbox, it triggers itself and repopulates... so if I select the 2nd or 3rd item in the dropdown, it repopulates and selects the first item again.
Am I doing something wrong, or is this normal? Should I put the first dropdown into an updatepanel instead and have it trigger itself, and in its own trigger, populate the 2nd listbox?
It appears that changing the value in the second dropdown is causing a postback, which it then sets the value to the default or first value. Try setting the dropdown's AutoPostBack property to false and EnableViewState to true.
Use the ASP.NET Ajax Control Toolkit CascadingDropDown instead.
EDIT: You need to set your UpdateMode=Conditional and control when your UpdatePanel's should update, by calling UpdatePanel2.Update().
I had this problem once.
This is a problem for update panel plus dropdown autopostback
By default ViewState for page is stored,so you do not need to change ViewState for control.
First,Change your UpdatePanel's UpdateMode property to Conditional UpdateMode="Conditional".This ensures that you can control postback since your dropdown always postback when you set AutoPostBack to true.
Second is in your method which you bind datasource into dropdown,after databinding is done.Update your panel by calling Update method of UpdatePanel updPanel.Update(); by
dropdown.DataSource = source;//I presume
dropdown.DataBind();
updPanel.Update();
Hope this helps.
I'm writing an ASP.Net webform with some DropDownList controls on it. Then user changes selected item in one of dropdowns, ASP.Net doesn't seem to handle SelectedIndexChanged event until form is submitted with a 'Submit' button click.
How do I make my dropdowns handle SelectedIndexChanged instantly?
P.S. It's a classic question I have answered too many times, but it seems no one asked it before on stackoverflow.
Setting the AutoPostback property to true will cause it to postback when the selection is changed. Please note that this requires javascript to be enabled.
You need to set the AutoPostBack property of the list to true.
Also, if you're populating the contents of the drop down list from the code behind (getting the contents of the list from a database, for example) - make sure you're not re-binding the data in every postback.
Sometimes people are caught out by binding the drop-down in the page load event without putting it in an If Not IsPostBack. This will cause the event not to fire.
The same is also true of repeaters and ItemCommand events.
if you are populating the dropdown list during page load then each time the page postback it will reload the list thus negating your postback method.
you need to be sure to load the dropdownlist only if (!ispostback)
Set the AutoPostBack property of DropDownList to true.