there. I have a gridview with a column of check boxes which was working when it was a small test project but when adding it to a page on my teams project it stopped firing the checkedChanged event. The check mark still appears or disappears but nothing fires. The only major difference is I was using an sqlDataSource object at first but for the new project i had to bind it to a database in the behind code.
Here's my html:
<asp:TemplateField HeaderText="Create Incident">
<ItemTemplate>
<asp:CheckBox ID="Selections" runat="server" ViewStateMode = "Enabled" OnCheckedChanged="CheckBox1_CheckedChanged" />
</ItemTemplate>
</asp:TemplateField>
and some simple behindcode:
protected void CheckBox1_CheckedChanged(object sender, EventArgs e)
{
Console.WriteLine("clicked!");
}
set AutoPostBack to True to enable post back
<asp:CheckBox ID="Selections" runat="server" ViewStateMode = "Enabled" OnCheckedChanged="CheckBox1_CheckedChanged" AutoPostBack="True" />
I found the solution. I added the conditional the block if(!page.isPostBack) around the stuff in my page load event.
Kept searching for about an hour till I found out that the actual reason why the OnCheckedChanged event was not firing on my page was due to duplication of names. Duh
An input control had a name 'submit' and there also exists a method in my JavaScript that is called submit(). The JavaScript interpreter was confused between the name of the control and a function, every time it needed to fire the event. Changed the name of the control and everything went back to working perfectly.
Related
I have an asp.net web form with several textboxes, buttons, and other controls. One of the buttons is supposed to trigger validation of content in some of the textboxes. This works fine, except that if validation fails, all subsequent postbacks of the page are prevented. Fixing the invalid values gets rid of the error messages, but postback still does not occur.
The validation is occurring within an AJAX UpdatePanel. I'm not sure if that matters or not.
I'm glad the workaround is fine for you, but for the benefit of others who land this page, disabling client side validation is far from an acceptable solution. So here goes:
Why it happened only when UpdatePanel was around, is still unclear to me, however:
As others have mentioned, the issue you were having is most likely because the unsuccessful validation attempt is preventing a further postback.
See also: Why won't my form post back after validation?
There is a variable called Page_BlockSubmit which is set to true when client side validation fails:
function Page_ClientValidate(validationGroup) {
....
Page_BlockSubmit = !Page_IsValid;
return Page_IsValid;
}
So when a __doPostBack occurs as part of, say, an OnSelectedIndexChanged of a DropDownList, there is this check:
function ValidatorCommonOnSubmit() {
....
var result = !Page_BlockSubmit; /* read the value */
....
Page_BlockSubmit = false; /* reset it */
return result;
}
Which will block the first time, but then clear the flag, so the next postback attempt should work.
The workaround, in my case, for a DropDownList's OnSelectedIndexChanged event, was to have a snippet added to its client-side onchange event:
<asp:DropDownList runat="server" ID="SomeDropDownList" OnSelectedIndexChanged="AlwaysDoSomething"
onchange="resetValidationState(this);">
....
</asp:DropDownList>
<script type="text/javascript">
function resetValidationState() {
// clear any postback blocks, which occur after validation fails:
window.Page_BlockSubmit = false;
}
</script>
You might get away with putting that snippet into the onchange itself.
except that after this button has been clicked no other button can cause a postback unless the validation errors have been corrected. So, btnDelete, which should not require validation of the textboxes, cannot postback until the textbox values are corrected
Don't see that behavior with following code..
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ErrorMessage="RequiredFieldValidator" ControlToValidate="TextBox1" ValidationGroup="pc">
</asp:RequiredFieldValidator>
<asp:Button runat="server" ID="btnSubmit" Text="Submit" Width="150" CausesValidation="true" ValidationGroup="pc" />
<asp:Button runat="server" ID="btnDelete" Text="Delete" CausesValidation="false" />
I could be totally off base here - but i think I see the problem. (I work mainly with devexpress controls so the rules can be a bit different). When validation fails, the whole page is set to invalid, so no postbacks can occur. Can it be since the delete button is not causing any validation, its not re validating after those editors have been changed to be valid?
We are using ASP.NET for one of our projects. However, when we are trying to read the SelectedItem or SelectedValue property of the DropDownList we are using in the callback function of a Link click, we are not getting the correct SelectedItem.
<FooterTemplate>
<asp:DropDownList ID="cmbTesters" ClientIDMode="Static" runat="server" Width="300px" DataSource='<%# PopulateTesterNames() %>' DataTextField="FullName" DataValueField = "PK_ID"></asp:DropDownList>
</FooterTemplate>
This is the DropDownList in the aspx file. The drop down is present within a GridView's Footer Row. We are invoking the following set of code on clicking a link.
if (int.TryParse(((DropDownList)dgCreateCPRVerificationResponse.FooterRow.FindControl("cmbTesters")).SelectedValue, out TesterID))
{
TesterID = int.Parse(((DropDownList)dgCreateCPRVerificationResponse.FooterRow.FindControl("cmbTesters")).SelectedValue);
}
The problem we are facing is that whatever value we choose, the SelectedValue is always of the first item in the list. We are using REST based URL defined in the global.asax file. Also note that this is not built on any framework.
Please help as soon as possible
Make sure to put the binding methods of the dropdownlist and the gridview inside if (!IsPostBack)
I'm trying to fire an event when a user clicks a hyperlink. But it would complain that the event is not defined:
<asp:HyperLink ID="HyperLink1" onmouseover="btnSubmit_Click" runat="server">www.google.com</asp:HyperLink>
<asp:Button
id="btnSubmit"
Text="Submit"
Runat="server" />
protected void btnSubmit_Click(object sender, EventArgs e)
{
btnSubmit.Text = "clicked a link!!!";
}
I see several problems.
You do not have any sort of click event setup on your hyperlink. You do have a "onmouseover" but based on MSDN's documentation there is no click event for that control.
You have a button defined, but no events associated with that button.
You have a function that appears to be an event handler, but the naming convention suggests that it is associated with the button that has no events.
Can you provide more detail of what you are trying to do? I assume the c# code you have posted resides in the code behind?
Update:
Try changing your code to this -
<asp:LinkButton ID="lb_Link" OnClick="btnSubmit_Click" Text="www.google.com" runat="server" />
Obviously this will not redirect you, but based on what your code does, it doesn't sound like you want a redirect...
The event you're trying to trigger is a server side event. You need to use client side code for what you want to do. Plus, there is no property known as onmouseover, you can add it as a client side event from code behind
HyperLink1.Attributes.Add("onmouseover","yourClientFunction");//this can be done in page load
Note: I am brand new at ASP.NET. I'm actually going to training on Monday, but we have a hot project that required me to dive in and get done as much as I can.
I've got a textbox on my page, and I would like it to call an event on the server whenever it is changed. I don't care if "changed" means changed and loses focus, or just whenever a keyup happens. Either case will work.
The issue is that, for some reason, whenever I change my textbox and then remove focus, the server-side method is not getting called. Viewing through the debugger in Chrome, I don't even see any sort of AJAX call being made that would inform the server that a textbox was changed.
My Code:
ASCX File
<asp:UpdatePanel ID="UpdatePanel2" runat="server">
<ContentTemplate>
<asp:TextBox ID="tempTagBuilder" runat="server"
CssClass="depBuilder_tempTagBuilder"
ontextchanged="tempTagBuilder_TextChanged" AutoPostBack="True"></asp:TextBox>
</ContentTemplate>
</asp:UpdatePanel>
ASCX.cs File
//whenever the text is changed
protected void tempTagBuilder_TextChanged(object sender, EventArgs e)
{
System.Diagnostics.Debug.WriteLine("Hit");
}
Anyone have a good idea of what my issue might be?
Update 1:
I got it working (somewhat). I had to go into the updatepanel's properties and add the textchanged event to the triggers collection. However, now whenever it sends the update it is emptying out the other textboxes on my page!
It doesn't fire because it's in an update panel most likely. Seems the updatepanel requires you to set a trigger for the event.
Problem with textbox inside updatepanel - not causing OnTextChanged event
In my project I have placed a dropdownlist in an updatepanel.what I wanted to do is to select a value from dropdownlist and use it in a session.
but whatever I do, it will always give me null value because of not checking "Enable AutoPostBack".and when I do this, it will refresh the page so this isn't what I wanted.
It sounds like you may not be using the UpdatePanel feature properly. If you have the UpdatePanel set to update when children fire events, only the UpdatePanel should refresh, not the entire page. The code below seems to behave similar to what you are seeking. When changing the drop down, only the update panel posts back to the server and when you refresh the page, you can get the value out of the session.
ASPX CODE
<form id="form1" runat="server">
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<div>
Current Time: <asp:Label ID="lblTime" runat="server" /><br />
Session Value: <asp:Label ID="lblSessionValue" runat="server" /><br />
<br />
<asp:UpdatePanel ID="upSetSession" runat="server">
<ContentTemplate>
<asp:DropDownList ID="ddlMyList" runat="server"
onselectedindexchanged="ddlMyList_SelectedIndexChanged"
AutoPostBack="true">
<asp:ListItem>Select One</asp:ListItem>
<asp:ListItem>Maybe</asp:ListItem>
<asp:ListItem>Yes</asp:ListItem>
</asp:DropDownList>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="ddlMyList"
EventName="SelectedIndexChanged" />
</Triggers>
</asp:UpdatePanel>
</div>
</form>
CODE BEHIND
protected void Page_Load(object sender, EventArgs e)
{
this.lblTime.Text = DateTime.Now.ToShortTimeString();
if (Session["MyValue"] != null)
this.lblSessionValue.Text = Session["MyValue"].ToString();
}
protected void ddlMyList_SelectedIndexChanged(object sender, EventArgs e)
{
Session.Remove("MyValue");
Session.Add("MyValue", this.ddlMyList.SelectedValue);
}
In order to get anything stored to Session, you have to submit it to the server.
Perhaps some more details on why you don't want the UpdatePanel refreshing would be helpful, and what you are trying to accomplish using the value in Session.
EDIT: Based on your comments, it seems to me that the solution would be to store the current .ascx file in Session, and set your DropDownList to have autopostback enabled.
So, on your handling of the "Next" and "Back" buttons, store an indicator for the correct .ascx to Session.
During your postback handling of the dropdownlist event, you could simply ensure that the current .ascx file is still being shown, by checking session for the correct file to show. When the result is returned to the client, nothing will appear to have changed, because the UpdatePanel is smart enough to realize it's the same content, and you will have successfully dealt with the dropdownlist value.
It sounds like you're doing way more work than you need to here. Have you looked into using an ASP.NET Wizard Control? http://msdn.microsoft.com/en-us/magazine/cc163894.aspx or just Google it.
If you still want to do it your way, you have to submit to the server (either with no autopostback + manual submit button click, or by enabling autopostback) since the Session is a server-side concept. HTTP is a stateless protocol, so the only concept of state has to be done outside of HTTP's domain. This means you're stuck storing state on the server (for instance, in the session) or, much more restrictively, on the client's computer (such as in a cookie).
thanks a lot I solved problem by controlling variables in Page_Load event.
If Label1.Text = 1 Then
Dim tempcontrol2 As Control = LoadControl("Page1.ascx")
PlaceHolder1.Controls.Add(tempcontrol2)
ElseIf Label1.Text = 2 Then
Dim tempcontrol2 As Control = LoadControl("Page2.ascx")
PlaceHolder1.Controls.Add(tempcontrol2)
End If
thank u for all answers