Is there a way to make a button click event run from the page load?
Yes, you can do that.
if your button has runat="server" you can access it from codebehind.
you could insert a click action on the button in the page_load event. but it's better to create a function with all actions to call both from button click and page_load.
<asp:Button id="btn1">Click here</asp:Button>
void Page_Load(object source, EventArgs e)
{
doThis();
}
void btn1_click()
{
doThis();
}
void doThis()
{
//click actions
}
Another way to do it is by javascript. find the button when document is ready and fire the click on the button.
You could wrap the logic behind the button click event in a function and call that function from the page load.
Related
Asp button click does not fire. I wrote Response.Write("404.aspx"); in to button click event in codebehind. But it does not fire. Here is the page with a fire problem button:
please click here
thanks.
Here is the code behind:
protected void bntTest_Click(object sender, EventArgs e)
{
Response.Redirect("404.aspx");
}
protected void btn2_Click(object sender, EventArgs e)
{
Response.Redirect("404.aspx");
}
It does not work because your submit button is not inside the form tag so it won't be able to post the submitted data and the same time, the click event will not fire as the page does not post, you can see below:
EDIT:
You have added a nested form tag that you can not because form tag can not be nested within another form tag. So just remove the nested form tag and it will work.
Try to restructure your project using these guidelines:
Only add form elements to aspx pages
Add main content to MasterPage from pages
Add any content that needs to be nested within a form to a UserControl that is placed within a page.
I have a user control inside an aspx page, after the aspx page loads, when I click some button inside that user control, I want the focus to come back to user control after that button click action is complete and the aspx page loads again.
You need to have an event in your user control that will allow the .aspx page to subscribe to that event so that it can set focus to the element in the user control after the form posts back, like this:
public class UserControlClass
{
// Define event that will be raised by user control to anyone interested in handling the event
public event UC_Button1ClickEventHandler UC_Button1Click;
public delegate void UC_Button1ClickEventHandler();
// Mechanism to allow event to be raised by user control
private void Button1_Click(System.Object sender, System.EventArgs e)
{
if (UC_Button1Click != null)
{
UC_Button1Click();
}
}
}
Now in your .aspx page, you need to subscribe to the event in the user control and say what method will actually handle the event, like this:
userControl1.UC_Button1Click += Button1_Click;
Finally, the click event handler needs to exist, like this:
public void Button1_Click(object sender, EventArgs args)
{
// Set focus here to user control element, text box for example
((TextBox)userControl.FindControl("TextBox1")).Focus();
}
In Page_Load I populate an asp:Table with a grid of images. I have a button that when pressed I would like it to repopulate the page with different images.
However it appears that when the button is pressed Page_Load is called again, followed by the script specified by the button. I thought that I could simply set a variable in the button script which is checked during Page_Load, but this will not work.
What is the most asp.netish way to approach this? Should I be populating my table somewhere other than in Page_Load, or should my button be doing something different?
Your button event gets called after page load. As such, you should put your button code in there.
I'm not terribly sure why you'd try to stuff all of your event code into Page_Load, but it's best to keep it separated.
GOOD
protected void Page_Load(object sender, EventArgs e)
{
MethodThatDynamicallyCreatesControls();
}
protected void MyImage_Click(object sender, EventArgs e)
{
MyImage.Property = newValue;
MyImage2.Property = newValue2;
PopulateTables(newValues);
}
BAD
protected void PageLoad(object sender, EventArgs e)
{
if (Page.IsPostBack)
{
//Check to see if "MyButton" is in the Request
// if it is, it's the button that was clicked
if (Request["MyButton"])
{
MyImage.Property = newValue;
MyImage2.Property = newValue;
PopulateTables(newValues);
}
}
}
As rick said, it's all a matter of understanding the postback.
page_load gets fired every time the page is refreshed. however in many cases, you only want certain things to happen on the first time a page is loaded. in your case, you want the default images to load. by putting all 'one time' events for a page load in a
if (!Page.IsPostback )
{
}
it will only fire on the first time the page is loaded. this is what you want to load your first set of images.
Then in your button click event (which triggers a postback), the code within the if statement will not execute again. and you can load your second set of images in your button's event handler.
That button you're using should call a method in your code behind,so you can know that the button is was clicked, ex:
protected void Important_ButtonClicked(Object sender, EventArgs e)
{
//do what I want to do
}
<asp:Button id="Button1"
Text="MakeChanges"
OnClick="Important_ButtonClicked"
runat="server"/>
Actually I understand what your problem is now, seems like you just have values being set in your page load with no condition check in you page load, so every time you have a postback it refreshes the page to original state, the reason for that is because everytime you trigger a refresh(postback) on the page, the pageload method is invoked, so you need to set original setting in your page load,but have them in the condition, as
if(!Page.Postback) which gets triggered the first time you visit this page. Which means this is where your defaults go and if(Page.Postback) is where your always true things should go. ex:
protected void Page_Load()
{
// this is where I want things to always happen whenever the page is loaded
//for example, no matter what happens I want a certain image in the background
if(!Page.Postback)
{
//set my values for the first and only time
}
else //hint Page.Postback
{
//you can play with the page here to make necessary changes
//but Button click method will still be invoke so thats where button click
//changes should be made
}
}
A PostBack happend when the page is reload. The first page load, Page.IsPostBack has value false. When an event happend, Page.IsPostBack has value true.
So doing the thing like this will definitely works
void Page_Load()
{
if (!Page.IsPostBack)
{
//do your first time binding data
}
How to: Create Event Handlers in ASP.NET Web Pages
EDIT:
Your state change events are not going to fire correctly if you re-bind controls(ie:DropDownList) data on every postback.
void Page_Load()
{
if (!IsPostBack)
{
//load your data
}
}
Is it possible to popup a modal(AJAX) on drop downlist selection.
I have a user control which has a ddl and another usercontrol which has that modal popup.On selection of specific item i need to popup modal.
Modal popup is in another usercontrol.
I did an example of how to do it entirely client side using a ClientEventPool - http://www.aaron-powell.com/blog/january-2009/fun-with-a-client-event-pool-and-modal-popups.aspx
For AJAX work avoid postbacks at all costs!
If I am reading you correctly, you will need to use either chained events or event bubbling to force the drop down selection to fire an event. Then your second user control must listen for that event, and fire the event that "shows" the modal popup.
Without testing code, your structure on the primary control might look like this:
public delegate void DDLHandler(int selectedValue);
public event DDLHandler DDLChanged;
public void DDLChanged(int selection)
{
if (DDLChanged != null)
{
DDLChanged(selection);
}
}
Then you drop down control has it's event wired to call the handler
protected void ddlOne_SelectedIndexChanged(object sender, EventArgs e)
{
//fire event handler for fetching value for this selection
DDLChanged(Int32.Parse(ddlMeasurementOptions.SelectedValue));
}
I am using an ASP.NET ModalPopupExtender on a page and would like to prevent the dialog from hiding when the user presses the ok button in certain conditions. But I can't seem to find a way.
What I am looking for is something like this
ajax:ModalPopupExtender
...
OnOkScript="return confirm('You sure?')"
...
if confirm is false, then the modal dialog doesn't disappear.
From my understanding in your specific situation you would not wire up the button, and just wire up a script to handle the conditional, then you can close it via JS.
The following JavaScript function will allow you to achieve this:
function conditionalHide(clientID)
{
if (confirm('You sure?'))
{
$find(clientID).hide();
}
}
You can wire this up to your asp:Button control in the Page_Load event of your page
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
btnOK.OnClientClick = string.Format("conditionalHide('{0}'); return false;",
panPopup_ModalPopupExtender.ClientID);
}
}
Some notes:
panPopup_ModalPopupExtender is your ModalPopupExtender
The return false; prevents a postback from occurring when the user clicks the button
You could hard-code the ClientID of the ModalPopupExtender, but this introduces an (additional) maintainance headache. The approach shown is the best one that I've found to alleviate this overhead