I'm at a loss over here. On the root of my application (default.aspx), I have a basic ASP.NET Button control on the page with an event handler wired up via its onClick event.
Since it's the root, hitting either / or default.aspx will bring you to this page. When clicking the button, the event handler is only getting called if the FilePath is in the url (default.aspx).
To be more clear:
whatever.com/default.aspx <------ The event handler gets called when the button is clicked
whatever.com <------ event handler is not getting called when button is clicked.
I should note, this page doesn't have much on it. No jquery files included, no javascript, nothing besides a DropDownList and this Button. The Web.Config doesn't have much in it either, at least nothing I can see that would have any impact on this.
<asp:Button ID="btnSelection" OnClick="btnSelection_OnClick" runat="server" Text="Submit" />
protected void btnSelection_OnClick(object sender, EventArgs e)
{
throw new Exception("Test"); // Only reaches here if /default.aspx is in the url
}
This is probably something small I'm missing. Any guidance would be greatly appreciated.
Check out this link:
Event Handlers Might Not Be Not Raised in a Default Document in IIS 7 or IIS 7.5 Integrated Mode?
If nothing, it should point you in the right direction.
Related
The click event works just fine on local, and not on production server, I have the postback when the button is clicked but it doesen't fire the button's event.
I've already spent 3 days seeking the problem with no result, please any idea ?
This is my simple code in page aspx:
<asp:Button runat="server" OnClick="BtnChangeLang_Click"
ID="BtnChangeLang" />
and the event method in code behind :
public void BtnChangeLang_Click(object sender, EventArgs e)
{
//// my code
}
Thank you for ur help.
In my Asp.Net Web Form,
Assuming that, I have Main_page and Save_button that it is on Main_page.
When I click Save_button, firstly Page_Load eventexecute and after this btnSave_Click button execute.
I thought that when I click button firstly and only button might execute.
Is it correct or my program doesn't work correctly ?
It is normal that Page_Load is executed first and event handlers afterwards. So your program behaves as designed.
Excerpt from MSDN on the page lifecycle:
Load
During load, if the current request is a postback, control properties are loaded with information recovered from view state and control state.
Postback event handling
If the request is a postback, control event handlers are called. After that, the Validate method of all validator controls is called, which sets the IsValid property of individual validator controls and of the page. (There is an exception to this sequence: the handler for the event that caused validation is called after validation.)
If you are interested in details on the lifecycle of an ASP.NET Page, have a look at this link.
Resolution
If you need to perform certain steps in Page_Load (or any other method on your page) only when the page is requested first, you can check the IsPostBack property and thus make your program behave as you describe in your question:
public void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
// Steps are only run on initial GET, not when request is a PostBack.
}
}
It is correct that load event fires first then button event handler. If you want to execute code only at first, but not when any postback check IsPostBack property.
I have a aspx page that has a Tab control, a few buttons and a User Control on it.
<dx:TabPage Text="Worker Information" Name="tabWorker">
<ContentCollection>
<dx:ContentControl runat="server" SupportsDisabledAttribute="True">
<uc:WorkerInfo runat="server" OnWorkerLoaded="On_Worker_Loaded" OnWorkerUnloaded="On_Worker_Unloaded" />
</dx:ContentControl>
</ContentCollection>
</dx:TabPage>
There are 2 custom events on the user control
public event EventHandler WorkerLoaded;
public event EventHandler WorkerUnloaded;
I have the event handlers in the main aspx page
protected void On_Worker_Loaded(object sender, EventArgs e)
{
btnNext.Enabled = true;
}
protected void On_Worker_Unloaded(object sender, EventArgs e)
{
btnNext.Enabled = false;
}
The On_Worker_Loaded event fires without an issue. I can debug and watch the button become enabled. My problem is when the screen loads the button is still disabled. In my aspx page I disable the button:
<dx:ASPxButton ID="btnNext" runat="server" Text="Next" Theme="MetropolisBlue"
onclick="btnNext_Click" Enabled="false"></dx:ASPxButton>
The 'Next' button is already disabled. This is why you can't really see it. I have framed it with the black outline. When I click that OK button the WorkerLoaded Event fires.
The only other disable is on the On_Worker_Unloaded Event Handler. I don't have it hooked up yet. There is nothing else that causes the button to disable. Any Ideas what I'm missing?
Thanks!
UPDATE
The User Control has a UpdatePanel in it. I don't know if that makes a difference but I thought I would include that. Something else weird happened I noticed. After enabling the button I noticed that if I did a postback the button would be enabled. Does that ring any bells for anyone?
It seems the loaded event is being called before the Enabled=false property is set.
In your debugger check to see whether the Enabled property is already false when the event is called.
Also, what triggers the WorkerLoaded event?
In the end I found a solution that works for me. I put the Next button and the Previous buttons inside their own Update Panel. After I did this everything worked without issue. Thanks for all the ideas and help.
Works:
protected void Page_Load(object sender, EventArgs e)
{
myButton.Click += new EventHandler(myButton_Click);
}
Doesn't work:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
myButton.Click += new EventHandler(myButton_Click);
}
}
Now, what I expected in the second example was for the eventhandler to be wired to the button only when it is not a postback (i.e. the first time the page is loaded), and then on any postback, the button would no longer run the method associated with the event. That doesn't seem to be the case --- from the very first load (not a postback), the button does nothing when clicked.
My suspicion is that this is related to the page life cycle --- but I'm not quite sure where this falls into that. If I understand correctly, the method associated with the event gets run after the page has posted back (even if you clicked it on the first time the page loads), but I'm referring to the wiring up of the event to the method with the EventHandler delegate, not the actual running of the associated method.
Note: this is purely an attempt to gain a better understanding of what's going on behind the scenes, and not an attempt to solve a real world problem.
You need to think about how the code is executed with each page request. What happens on the server is that a class instance is created for each request and if the line of code
myButton.Click += new EventHandler(myButton_Click);
is conditional it means the event handler is not wired to the event on postback.
In other words if you write something like
<asp:Button ID="myButton" runat="server" OnClick="myButton_Click" />
This translates to the code you wrote and the event gets wired with each request.
The problem is, the event handler can only trigger when it IS a postback. The wiring of event handlers affects this instance of the class only. When a postback occurs, a new instance of your page is created and the event handler is no longer wired. You need to wire it in order for it to get triggered.
The best thing to do is always wire the event handlers. There's no reason not to.
If it is not a Postback, it means that the user just requested a page (HTTP Get request) with typing the URL in the browser (or clicking a link, or...).
If the user clicked on a button, then the browser makes a HTTP Post request, which on the server side, ASP.NET marks the page that is requested with setting the property IsPostBack to true of the page object.
See the answer on this question.
I guess what you intend to do is disable the button on postback.
You can do that by setting the enabled property to false.
protected void Page_Load(object sender, EventArgs e)
{
if (IsPostBack)
{
myButton.Enabled = false;
}
}
Practically I don't need it. But a little curiosity is running on my mind as my event handler function written for running in the server is not called. I have dragged a html button element and put it inside the form element with attribute runat="server"
Now if I double click on the button inside design view, it redirects me to a javascript block on which the event handler function is created. I erased it and write my own in the code behind file. Now when run the page on the server and click on the button, the event handler function is not called.
I want it to be run. Any way ?
You are confusing between two different events: the onclick provided in the editor is the client side click event, handled with javascript code.
The server side, c# based event handler can be added to such a button if you markup it with
runat="server"
,attribute and add a server side handler to it (assuming Button1 is the id of your button)
Button1.ServerClick += new EventHandler(Button1_ServerClick);
the markup for the html input doesnt expose the server side event to add a handler through the markup, but you can add the code i pasted above within your page_load/init events
What is your button like? try this:
<button runat="server" ID="myButton" onClick="YourFunction">My Button</button>
ASPX:
<button runat="server" id="htmlButton1" name="htmlButt" onserverclick="butt">
foo</button>
CS/Code-behind:
protected void butt(object sender, EventArgs e)
{
Response.Write("butt clicked!");
}
You'll have to write the handler (manually) - the IDE will not auto-magically wire it for you (you wire it yourself with onserverclick).