Firing Postback in ASP.NET Without javascript - asp.net

Is this possible?
EDIT
I want to user the asp:ListView
List item
I want to use it for editing
I dont want the postback to use Javascript when I put it into the edit mode
I've been trying to use a to do this instead of a link button but to no avail.
.

The only way to trigger a PostBack without JavaScript is by using a submit button. This is an HTML limitation, not an ASP.NET one.
I'm a little unsure of what you're trying to do without more detail. If I knew more specifically what you're trying to accomplish I could give you more details.

Like you mentioned in your post, you could use the <a> tag to send the user to the page you want.
You can add information to the link like so:
Click here for a new item
Then in the page load of newpage.aspx you can check what the action the user selected was, the query parameters are stored in the Request (Language is C#).
protected void Page_Load(object sender, EventArgs e)
{
string action = Request.Params["action"];
if(!String.IsNullOrEmpty(action))
{
switch(action)
{
case "newitem":
//handle the new item action
break;
case "deleteitem":
//handle the delete item action
break;
//handle other actions.
}
}
}
EDIT: You should be aware that the <a> tag will send the user to the page specified, the page though will act as if it is the first time the user has visited the page. With that said, the page variable IsPostBack will be false.

Related

Post back and browser back button issue in asp.net

I am working on web application. I have a grid that shows data to the user. When user click on the any row of the grid, it redirects user to another page, as we have a asp link control on the a column.
Issues
My code is like
if (!Page.IsPostBack)
{
//CODE
}
When user click on the BROWSER BACK button, it does not execute the CODE. Simply show the data from CACHE.
How can I execute the CODE , on browser back button click ?
It's a global problem with ASP.Net. Most of developers thinks like Windows developer. It ends with a postback for mostly any action, including navigation actions.
To solve such problems:
Avoid using button to change page. Generate an hyperlink with the target url.
Wrap parts of the page within an update panel. The benefits is that the browser won't see a page change after each postback. Then you will be able to "refresh" the page without warning dialog
When populating a grid, instead of "selecting" a row from codebehin, generate a link to the same page with "?ID=42" in the url, and bind this value to the grid as the selectedvalue
The root cause of this "evil" behavior, is that postback are issued using HTTP Post request. Then, the browser requires to repost the page to rebuild it.
Using the technics mentionned above, you are issuing GET request. This kind of request doesn't require to resubmit anything.
Try Disabling browser cache for the page that you don't want to cache.
protected void Page_Load(object sender, EventArgs e)
{
Response.Cache.SetExpires(DateTime.UtcNow.AddDays(-1));
Response.Cache.SetValidUntilExpires(false);
Response.Cache.SetRevalidation(HttpCacheRevalidation.AllCaches);
Response.Cache.SetCacheability(HttpCacheability.NoCache);
Response.Cache.SetNoStore();
if (!Page.IsPostBack)
{
//CODE
}
}

ASP CompareValidator and NOT submitting form

I have a textbox and a submit button. The textbox is a date-entry field.
Attached to it, I have a compare validator with the type set to "date". It does validate and show an error message.
Problem is, the user can still click on the submit button. I'd like to prevent that. If the user has entered something like 03/hello/2011, he or she should not be able to submit the form.
How can I accomplish this?
Any ideas?
Thanks,
Jason
Associate the validator and the submit button in a single validation group. Both of them have the property validation group. Provide a name say pageValidation to both the control's property.
I've encountered this problem myself, that a page with validation errors can still continue on to submission when the user clicks the submit button.
What you can do is something like this :
protected void submitClicked(object sender, EventArgs e)
{
if (!Page.IsValid)
{
// somehow the user was able to submit their form even though there are
// validation errors. Stop here and let ASP.NET present the error messages
// to the user
return;
}
// do submission stuff here like putting things in the database
}

is there any method for know on which hyperlink user has clicked in asp.net?

hi actually i want to store value that has been clicked by user on web page for instance.
suppose this is my web page content of list
**
**google.com**
**yahoo.com**
**facebook login**
**stackoverflow.com**
**
now suppose user click on facebook login
then how to know that user has clicked on facebook login actually i want to keep record for further processing.
Abatischev's suggestion will work, but there's an easier method that doesn't involve making AJAX calls if you don't want to go through the hassle.
Instead of having the link go directly to the page that you're linking to, you should have it submit to your asp.net page. You can then record the click there before redirecting to the destination page.
Client-side way:
Before finish the page render, add programmatically onclick event to each hyperlink, call on click an async JavaScript script to record url
Server-side way: (extending #Justin's answer)
<asp:LinkButton runat="server" OnClick="urlGoogle_Click">google.com</asp:LinkButton>
protected void urlGoogle_Click(object sender, EventArgs e)
{
DataBase.Record("google.com");
this.Response.Redirect("http://google.com");
}

ASP.NET AJAX issues when using UserControls

I Have a UserControl called TenantList.ascx which contains a slightly modified GridView from DevExpress (Web.ASPxGridView). This control makes Callbacks without causing a postback which is exactly what I need.
The specific event I need to react on is CustomButtonClicked. I have made my on OnCustomButtonClicked event on the usercontrol TenantList.ascx that fires when the the GridView CustomButtonClicked event fires.
I have an eventhandler on the page where I use the UC. When I debug using VS I can see that I get into the eventhandler as I am suppose to.
My Eventhandler looks like this:
protected void uc_TenantList_CustomButtonCallback(object sender, ASPxGridViewCustomButtonCallbackEventArgs e)
{
Tenant tenant = (Tenant)uc_TenantList.GetGridView().GetRow(e.VisibleIndex);
switch (e.ButtonID)
{
case "btn_show":
ShowRow(tenant);
break;
case "btn_edit":
EditRow(tenant);
break;
case "btn_delete":
DeleteRow(tenant.Id);
break;
default:
break;
}
}
private void EditRow(Tenant tenant)
{
uc_TenantDetails.SetTenantData(cBLL.GetTenant(tenant.Id));
UpdatePanel1.Update();
}
The EditRow function get's called and the UserControl TenantDetails.ascx gets filled with data correctly. However the UpdatePanel1.Update(); is not updating the panel where my TenantDetails UserControl is in.
However if i call UpdatePanel1.Update(); from a normal control registered to the ScriptManager it updates just fine.
protected void Button1_Click(object sender, EventArgs e)
{
uc_TenantDetails.SetTenantData(cBLL.GetTenant(17));
UpdatePanel1.Update();
}
That works without a problem... I am 100% stuck and without any idea of what might be the problem here.
Any suggestion is welcome!!
Cheers
The Real Napster - In real trouble :)
Okay solved this issue
What I needed to do was to enable postback on the gridview control inside my usercontrol.
Then place the Gridview usercontrol in a updatepanel and still keep the details usercontrol in another updatepanel.
That way it all worked out. Not impressed by the solution though. Looks a bit ugly.
Make sure that your update panel is set to always update (not conditionally). You may also find the information in this articles useful:
http://www.asp.net/AJAX/Documentation/Live/overview/PartialPageRenderingOverview.aspx
http://msdn.microsoft.com/en-us/library/system.web.ui.updatepanel.update.aspx
The first link will give you some history regarding Partial Page Rendering, the second gives you some more information about the Update method.
From the documentation calling UpdatePanel.Update will cause an update panel to be re-rendered on the client after calling, but only if the UpdatePanel is set to Conditionally update. If it is set to always update this should throw an error.
If your update panel is set to always update, could it be that it is nested in another UpdatePanel which has its update mode set to conditional?

Refresh the page after a postback action in asp.net

I have command button added in my asp.net grids. After performing an action using that button, we refresh the grid to reflect the new data. (basically this action duplicates the grid row).
Now when user refresh the page using F5, an alert message is displayed (to resend the information to server) if we select "retry", the action is repeated automatically.
I know this is a common problem in asp.net, how can we best handle this?
Search for GET after POST - http://en.wikipedia.org/wiki/Post/Redirect/Get - basically, redirect to the current page after you're finished processing your event.
Something like:
Response.Redirect(Request.RawUrl)
If you think you don't need postback paradigm, you might want to look at ASP.NET MVC.
The problem is that asp.net buttons perform form posts when you push a button. If you replace the button with a link your problem should go away. You can also use a button that performs a javascript function that sets the document.location to the address of your page.
If I well understood, you simply have to check if you are in a post-back situation before populating your grid.
Assuming you do that on Page_Load, simply surround the operation with post-back test like this:
private void Page_Load(object sender, EventArgs e)
{
if(!this.IsPostBack)
{
// populate grid
}
}
You need to call response.Redirect(Request.Url.ToString());
or you can wrap the grid with updatepanel and after every command bind the datasource to grid
Inside your <asp:Repeater> tag put this:
EnableViewState="false"
This will cause your control to refresh every time the page loads, no matter if it's a postback or not.
for example:
if you click on 'button' system will catch the event 'button_click'.
if you refresh the page, system will re execute again the same event.
to don t have this problem, in your event insert :
on your event
private void button_click(object sender, System.EventArgs e)
{
button.Enabled =false;
button.Enabled =true;
}
is what you meant?

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