I have a problem on one page in my entire solution where it seems the on click event for the image button is not firing.Firstly let me describe the relevant parts of the website.
There is a total of four pages involved in this problem.Pages A-D.
I start on Page A from which I navigate to Page B via an ImageButton which works.Here some data is captured and I navigate further to Page C via another ImageButton which works.On Page C I have two ImageButtons,these are the ones giving me trouble.One is simply supposed to take me back to Page A and the other takes me to Page D.The one that takes me to Page D I send some arguments along.
Now if I click on either of these I get taken back to Page A,however when debugging even on the one thats supposed to take me back I cant see the code being hit.Here is how I have my buttons defined in the aspx page:
<asp:ImageButton ID="ImageButton1" runat="server" ImageUrl="~/images/backBtn.jpg" />
<asp:ImageButton ID="ImageButton2" runat="server" ImageUrl="~/images/nextBtn.png" />
And my code behind for them is as follows:
Protected Sub ImageButton1_Click(sender As Object, e As System.Web.UI.ImageClickEventArgs) Handles ImageButton1.Click
Response.Redirect("pageA.aspx")
End Sub
Protected Sub ImageButton2_Click(sender As Object, e As System.Web.UI.ImageClickEventArgs) Handles ImageButton2.Click
Response.Redirect("pageD.aspx?option=4&ref=" & lblInfo.Text)
End Sub
The buttons aren't in a update panel.Things I have tried to do to fix this :
Remove them and readd them from scratch.
Turn into normal asp:Button to see if its a problem with ImageButtons,problem was still there.
Set AutoEventWireUp to true.
Explicitly set OnClick in aspx to the method.
Set CausesValidation to false.
None of the above has worked.If anyone can help I would be very gratefull.
No url rewriting or default document involved ?
Could it be some code in pageC or some base class, which triggers on postback before click-events handling, and redirects to page A ?
(maybe some error handling which redirects to pageA)
Related
I have a JS function in an ASPX page that performs a __doPostBack to a vb.net code behind. The problem is that it is forcing the page to refresh. How can I prevent this? My code below...
JS:
__doPostBack('', 'test');
VB.NET:
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If IsPostBack Then
Select Case Request.Form("__EVENTARGUMENT")
Case "test"
RadMediaPlayer1.Source = url
End Select
End Sub
Thanks!
There is one easy way, and then one hard way.
The first issue? asp.net web pages are in fact designed to near ALWAYS have and endure post-backs.
This quite much means that any button, any combo box, or just about anything on that page to run some code behind WILL cause a page post-back.
And thankfully due to automatic "view state" management, most controls, and even a grid view, or even a combo box selection will correctly maintain its values for you (its view state).
So, if you don't want the whole page to post back and refresh?
Then you can drop in a plane jane asp.net button, and say whatever it is you want to "only update", then try using what is called a update panel.
Try a quick test page like this:
<form id="form1" runat="server">
<div>
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
<br />
<asp:Button ID="Button1" runat="server" Text="Button" />
</div>
</form>
And our code behind like this:
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
End Sub
Protected Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
TextBox1.Text = Date.Now
System.Threading.Thread.Sleep(700)
End Sub
Now, I put in a 3/4 of second delay - just to help you see the effects of this (you don't want that delay sleep() in your actual code.
Ok, now run the above page, click on the button. You see the traditional post-back, you see the browser "spinner"/wait occur, and then the text box is updated.
Now, lets use what is called a update panel - and I am going to suggest you try one.
You can even dump/drop the JavaScript you have now.
So, you have to drop into the page a script manager, and then move your content inside of he update panel. It will now look like this:
<form id="form1" runat="server">
<asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager>
<div>
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
<br />
<asp:Button ID="Button1" runat="server" Text="Button" />
</ContentTemplate>
</asp:UpdatePanel>
</div>
</form>
Give above a try - note how the page don't post-back any more? How cool is that!!!
So, add update panel, content template. And move your button, and the adMediaPlayer1 into that panel.
You don't even need to adopt any JavaScript here. Drop in a plane jane button, and just have normal code behind for that button. Say like this:
Protected Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
RadMediaPlayer1.Source = "some real url goes here"
End Sub
A few things:
While this looks, feels and appears to NOT do a post back and the .net system will wire this up for you automatic - VERY much like a ajax call?
Don't put too much inside of those update panels.
and keep in mind, while this does not seem to do a post back? In fact this results in what we call a "partial" post back. The page load event even will fire.
Note that code behind CAN ONLY now modify controls inside of that update panel. Other controls on the page are off limits. (unless you move them into that update panel also).
But, dump your JavaScript button or code for the post back. Just move in the media control and your button to inside of that up date panel. Give this a try - you not see a post back - you not see the browser "spinner"/wait run at all.
This feature is great - but a not a cure all.
The next way to do this?
Is you can setup what is called a ajax call. This can call code behind, but keep in mind the code behind can't update controls on the page (due to no post-back). If you don't do a post-back, then code behind can't touch controls on the page.
This would suggest that you have a client side button - click on it, it runs JavaScript, calls some code behind, code behind returns a result, and then in JavaScript you stuff/change the URL of the given control. Since you changing that URL in pure JavaScript at this point? You probably don't even need to write or call code behind anyway.
but, try the update panel - they are very useful. But, keep in mind behind, the .net system is doing a bit of fakery to achieve this goal, and what a partial page post- back does occur.
Edit: pass value from js and click button
So, as noted, if you have a post back, you get page refresh!!! - that's what the command does and means!! So, you can't say I dont want to post back and not refresh the page, and then do a post back!!!
However, as noted, your js code is "obviously" a much larger example, and you sharing of JUST the __DoPostBack() in js is as you noted a larger set of code and routines here.
However, I still suggest you use a update panel.
You can keep 99% of your js code now, and just remove the _dopost back.
Move your case statement code to a button. (yes, a button click code stub).
What we THEN do is this:
The js code can figure out and do whatever it needs. Obviously we reach a point in which a VALUE of some type has to be passed to the server. And then what we will do is then use js code to CLICK the button - the ONE inside of the update panel. This will and should prevent a page refresh. And we pass the value by using a asp.net hidden field control (you could even use a hidden text box - but it don't matter - hidden field is probably better).
So, the pattern, and code will look like this:
We drop a button, hidden field, and that other video or whatever control is is the page - all inside the update panel.
then your js code? It runs, gets the final value. We shove that value into a hidden field control, and then use js to click the button - also inside of that panel.
Thus, you move your on load code + case statement to the button click code.
Like this:
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
End Sub
Protected Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
' get value passed from js
Dim strMyValue As String = Me.HiddenField1.Value
Debug.Print(strMyValue)
Select Case strMyValue
Case "test"
Case "zoo"
Case "my fun test"
End Select
End Sub
And the markup is this:
<asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager>
<div>
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
<br />
<asp:Button ID="Button1" runat="server" Text="Button" ClientIDMode="Static" />
<br />
<asp:HiddenField ID="HiddenField1" runat="server" ClientIDMode="Static" />
</ContentTemplate>
</asp:UpdatePanel>
<asp:Button ID="Button2" runat="server" Text="js post back"
OnClientClick="mypost();return false;"
/>
<script>
function mypost() {
// set value to pass to button click
$('#HiddenField1').val("my fun test")
$('#Button1').click()
}
</script>
</div>
So, in place of your doPostback, you set the hidden field, and then with js click the button. (once you get this workng, then hide the button with style="display:none"
Of course, you proably have a bunch of postback in your code.
So, make a js function called MyPostBack, say like this:
function MyPostBack(sValue) {
// set value to pass to button click
$('#HiddenField1').val(sValue)
$('#Button1').click()
}
Now, you can replace all your _DoPostBack('', 'test')
With MyPostBack('test')
So, in the update panel, put the hidden field, the button, and that other control. And your js code will now "click" that button in the panel.
Note that the js code above does assume you using jQuery. However, you can code in pure js, and not necessary use jQuery short hand as I did above.
The bug I'm trying to solve is that the buttons on my .aspx page that correspond to methods in the .vb file all return a blank page without actually getting to the vb code (no breakpoints I've put on these methods get triggered). There is no redirect as the URL doesn't change it simply registers the button click and then its handler gives a blank page. I thought at first that this would have something to do with doPostBack but even after putting "CausesValidation="false" " this still continues. I've recreated the button in the designer window just to be extra sure that the button points to code and the program knows it but still no luck.
Here is what the button itself looks like:
<asp:Button ID="btnFreshTest" runat="server" CausesValidation="true" Text="Save User" ClientIDMode="Static" width="100px" ToolTip="Save changes" Height="35px" />
Here is what the visual basic method code looks like, yes its simple but this is for a test:
Protected Sub btnFreshTest_Click(sender As Object, e As EventArgs) Handles btnFreshTest.Click
Dim testString2 As String = "abc"
End Sub
Even if you don't have a solution given the lack of information, if you have any pointers that I could use like places to look for an error or somewhere to put a breakpoint with chrome tools, I would greatly appreciate it.
Ok, so we drop this into a page:
<asp:Button ID="btnFreshTest" runat="server" CausesValidation="true"
Text="Save User" ClientIDMode="Static"
width="100px" ToolTip="Save changes" Height="35px" />
So we see this:
Now do NOT JUST TYPE in the event stub - double click on the button above, and you now have this:
Protected Sub btnFreshTest_Click(sender As Object, e As EventArgs) Handles btnFreshTest.Click
Dim testString2 As String = "abc"
Console.WriteLine("Value of test string = " & testString2)
End Sub
And when we run, then we get this:
So, you may well have messed up the event, but if you JUST drop in that button (say a cut + paste from example code), then the event stub will not automatic wire up - you have to click on it.
And note VERY close that the button does not see, nor have a event defined IN the markup - but you will see it in the property sheet for that button like this:
And you can in markup actually force/type in the event define, and intel-sense will do this:
In fact you MUST DO this if the button is inside of a repeater/gridview/list view etc., since you can't double click on the button in the desinger anyway. So additional information here in regards to if some data repeating type of control is surrounding the button. A button is often part of MUCH markup, and depending on how it is nested, a simple click on the button is not always possible.
So, try typing in the OnClick= (and when you hit "=", you should get intel-sense, and try wire up the button that way.
I've searched the forums and have yet to find a soln to my specific problem. I'm writing an asp.net aspx page with
<asp:Button ID="Add" OnClick="Add_Click" runat="server" Text="Add" CausesValidation="False"/>
where Visual Studio even autofilled my OnClick function, and my VB code behind function looks like this:
Protected Sub Add_Click(sender As Object, e As EventArgs) Handles Add.Click
Server.Transfer("TimeReportingAdd.aspx", False)
End Sub
I have another page with a button set similarly and it works fine. Does not even hit event during a debug. The main page (TimeReporting.aspx) just refreshes on the click and I would like it to redirect to another page (TimeReportingAdd.aspx). The button was not copied but created new and the event was created by double clicking in the designer. runat="server" is present in all my content headers etc. I don't think my TimeReporting.aspx page header needs any validation elements because the page that works doesn't have them. The Add button is declared as follows in my vb code behind:
Protected WithEvents Add As Global.System.Web.UI.WebControls.Button
Also, the button that works in another page is easier, doesnt even have onclick or validation:
<asp:Button ID="Button1" runat="server" Text="Query" />
Protected Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
...
End Sub
I've tried deleting the button and adding it again multiple times. Thanks in advance!
Please remove OnClick="Add_Click". This will fix your problem.
There are two things you need to consider:-
When you add OnClick, this means you want to handle click in Java Script.
To handle click in server side, you provide a method in code behind with Handles clause.
First approach overrides second one.
I was able to get this to work by giving this property in my button:
PostBackUrl="~/TimeReportingAdd.aspx"
It was posting back to the initial page TimeReporting.aspx
I've found this question asked countless times, but the answers haven't worked for me:
I have an asp:Dropdownlist that is dynamically bound from an asp:Objectdatasource. A button calls a codebehind function to store the selected value. However, in the click event function the value of the dropdown is always reset to default, AFAIK due to a postback that is called before the click event handler. When debugging I've checked that ViewStateMode is enabled and EnableViewState is true. I've been stuck with this for hours now, does anyone have a clue?
ASPX markup:
<asp:DropDownList runat="server" DataSourceID="AvailableNivamalerODS" ID="AddNivamalerDDL" />
<asp:ObjectDataSource runat="server" ID="AvailableNivamalerODS" TypeName="Nivamaler.NivamalerPresenter"
SelectMethod="GetAvailableNivamalers"></asp:ObjectDataSource>
<asp:Button runat="server"
Text="Legg til"
OnClick="AddNivamalerToTjstpl"
ID="AddNivamalerBtn"
UseSubmitBehavior="False"
CssClass="ui-button ui-widget ui-state-default ui-corner-all ui-button-text-only"/>
Codebehind
Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
If Not Page.IsPostBack Then
AddNivamalerDDL.DataBind()
End If
End Sub
Click event handler:
Protected Sub AddNivamalerToTjstpl(sender As Object, e As EventArgs) Handles AddNivamalerBtn.Click
Dim nivamalerId As Integer = AddNivamalerDDL.SelectedValue
'Here nivamalerId is always the default value
End Sub
Cheers!
EDIT
The replies to previous question have basically said to put the data binding in the Page_Init method or the Page_Load method after !IsPostBack, which didn't help me.
Also a disclaimer: This is a legacy project with tons more code (the relevant code is new), but I tried to snip out the relevant bits. As far as I can see the rest of the code shouldn't affect this, but I can't be certain as I am still fairly new to ASP.Net
Put your page_load code into the page_Init section. The asp lifecycle will make the dropdown list databind() be absolutely meaningless if it is in the page load section here because a Postback causes the whole page to resubmit itself to the point of page_load and since you have the if not ispostback statement, it will reload the page structure but won't run your page load code and that is where you are losing your value. Other than that the code is fine.
I solved it, and as has been pointed out, the posted code is incomplete: The dropdown is inside a JQuery-ui dialog, which makes the dropdown lose its state. I ended up with a workaround with a Javascript function which copied the selected value to a hidden field outside the dialog and using the hidden field value in the codebehind
I currently have a asp hyperlink control that links to a login page and there is a button called sign out which clears the session variables. I was thinking of trying to clear the session variables with the hyperlink control without going to the login page. Is there any way I could do this maybe with an IF statement?
This is my code for the hyperlink control:
<asp:HyperLink runat="server" ID="Log_out" Class="sign_up" visible="false" NavigateUrl="/Pages/login.aspx">Sign out</asp:HyperLink>
According to the comments, you need this link's code in VB.NET (you only mentioned .NET): https://stackoverflow.com/a/7231659/284240
If so, here it is. Let us know if you are looking for something else.
Public Sub linkGoSomewhere_Click(sender As Object, e As EventArgs)
Response.Redirect("Default.aspx")
End Sub
See this link for how to set onclick event in code behind:
How to code a Button's Click Event?