I have simple aspx page that has a form and a input field in it something like below.
//basket.aspx
<input type="text" id="TotalPrice" runat="server" name="TotalPrice" value="100" />
<asp:button ID="btnBuy" runat="server" Text="make payment" PostBackUrl="~/payment" />
</form>
This is going to payment.aspx but when I debug the Request.Form in the page load of the payment.aspx, I cannot reach the TotalPrice value like Request.Form["TotalPrice"]. What is the best way to make a post to another aspx page to get values ? Why the way I am trying to does not work ?
You should be using PreviousPage property on the target page.
Here is an article on how to make cross post backs work
Related
I have a simple ASP.NET page with a MasterPage. Within the MasterPage, I have two login fields:
<input type="text" runat="server" id="txtUserName"/>
<input type="text" runat="server" id="txtPassword"/>
When the controls are rendered to the page, ASP.NET renders the following:
<input type="text" runat="server" id="ctl00_txtUserName" name="ctl00$txtUserName"/>
<input type="text" runat="server" id="ctl00_txtPassword" name="ctl00$txtPassword"/>
If I understand correctly, the name attribute corresponds to the UniqueID property of a control. However, when I'm debugging Page_Load and attempt to view the UniqueID of these fields, they have different values (ctl0$txtUserName and ctl0$txtPassword respectively)!
Note that this does not seem to be an issue on all pages using this MasterPage. Most of them work correctly and use ctl0$txtUserName and ctl0$txtPassword in both rendering and Page_Load.
Any idea what might cause ASP.NET to render a different UniqueID for a control than it uses in Page_Load?
I'm still not sure what was causing the generated UniqueIDs in the MasterPage to be different in Page_Load than when rendered to the page. However, I was able to get around the issue by storing the UniqueIDs of these fields in hidden fields. I was then able to access the values directly in the Request.Form collection.
In other words, I did this:
In the MasterPage -
<input type="text" runat="server" id="txtUserName"/>
<input type="text" runat="server" id="txtPassword"/>
<input type="hidden" id="txtUserNameUID" value="<%=txtUserName.UniqueID%>"/>
<input type="hidden" id="txtPasswordUID" value="<%=txtPassword.UniqueID%>"/>
During Page_Load of the child page -
string username = Request.Form[Request.Form["txtUserNameUID"]];
string password = Request.Form[Request.Form["txtPasswordUID"]];
Hope this helps anyone else struggling with UniqueID weirdness in ASP.NET!
Weird quirk I just became aware of: any wrapping controls that are runat server must also have IDs. For instance, if you have a panel around the control, i.e. whatever "ctl00" is, it must be assigned an ID. If it is not set, it will be allocated one and this can change.
This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
Read Post Data submitted to ASP.Net Form
I have a google checkout "buy now" button, and am trying to add dynamically created content to send when it's clicked. Using the original html is proving a bit difficult so I want to create an ASP.Net ImageButton Instead of that.
I've succeeded in creating the button with the right image, and hooking it up to an event handler in the codebehind.
However, I'm not sure what exactly happens when the original button is clicked, in order to try and emulate it in the new ImageButton.
The original code is:
<form action="https://sandbox.google.com/checkout/..." id="Form1" method="post" name="..." target="_top">
<input name="item_name_1" type="hidden" value="..." />
...
<input alt="" src="https://sandbox.google.com/checkout/buttons/buy.gif?merchant_id=..." type="image" />
</form>
And I want to place a dynamically created item_name_1.
What do I have to do in the Button1_Click method for that?
The short, concise and usefull version:
Html:
<form id="__parent" action="..." method="post" runat="server">
<input id="__child0" name="type" type="hidden" value="button" runat="server" />
<input id="__child1" name="name" type="hidden" value="teh_button" runat="server" />
<input id="__child2" name="value" type="hidden" value="Hello?" runat="server" />
</form>
tehfile.cs:
<%# Page Language="C#" CodeFile="tehfile.cs" %>
String
_type = __child0.Value,
_name = __child1.Value,
_value = __child2.Value,
_element = String.Format(
"<{0} {1}=\"{2}\" {3}=\"{4}\" {5}=\"{6}\" />",
"input",
"type", _type,
"name", _name,
"value", _value );
Literal _lit = new Literal( );
_lit.Text = _element;
__parent.AddControl( _lit );
To post that data to another server on the ASP.NET server-side, you are going to need to use something like the WebRequest class.
Or also in order to post a form, you can use a remote post class like any of the ones here: Remote HTTP Post with C# , the answer by #BobbyShaftoe is the one i've used in many projects.
Same question/POST here. I would have commented instead of answered, but seems this is a better/formatted way to get to bottom of it all:
In your comment to #MarcusHansson's answer:
I fail to see how this addresses the question of how to use the codebehind to send the information
You are mixing server side with client side submission methods.
If you want to submit using "code behind" you must implement server-to-server HTTP Post. In the context of Google Checkout, I've provided that link in your other post.
Your client side is using an HTML FORM which in, and of itself is how you "send the data". You can try all sorts of client-side submission processes, but at the end of the day, it is a client-side (Javascript) method.
What is "dynamic" about your buy now button? It's meant for a single item (at a time) purchase. Why can't you construct all the variables you need at the same time you create the button? What are you adding (that requires another redirect or postback)?
I'm working on making some changes to a Dot Net Nuke website with a customized skin. I found out that the header to the skins file was located in 'Default.aspx' here.
The form has some very strange behavior. I have had to disable the enter button because pressing within the form causes the webpage to go to "/HOME.aspx" however that action is never specified within the Default.aspx.
The code is as follows.
<dnn:Form id="Form" runat="server" ENCTYPE="multipart/form-data" >
<asp:Label ID="SkinError" runat="server" CssClass="NormalRed" Visible="False"></asp:Label>
<asp:PlaceHolder ID="SkinPlaceHolder" runat="server" />
<input id="ScrollTop" runat="server" name="ScrollTop" type="hidden" />
<input id="__dnnVariable" runat="server" name="__dnnVariable" type="hidden" />
</dnn:Form>
The form after being processed displays in the browser as.
<form name="Form" method="post" action="/HOME.aspx" onsubmit="javascript:return WebForm_OnSubmit();" id="Form" enctype="multipart/form-data">
What I want the code to display as is simply.
<form name="Form" method="get" action="/SearchResults.aspx" id="Form">
I tried removing the dnn code with the html directly but removing the dnn form causes the website to crash.
EDIT
What I'm trying to do can be seen at http://www.ontariosheep.org
Notice if you press the button the search works but pressing enter causes the page to refresh.
You can use some Javascript to do this:
jQuery('#SearchBox').keypress(function(e){
if(e.which == 13){
e.preventDefault();CallSearchPage('http://www.ontariosheep.org/SearchResults.aspx');
}
});
You would need to put that in script tags and also in a jQuery document ready area... like
<script>
jQuery(document).ready(function(){
//code above here
});
</script>
Changing the behavior of the form in DNN is not something you are going to do easily. DNN uses the ASP.NET Web Forms model, so the action for the page is always the current page.
If you want to customize this the only real way is to modify the form action via JavaScript on a specific page, but note that doing that prior to a button click or similar trigger WILL break all administration functions on the page that require a postback to the server.
What are you trying to accomplish?
I found this article on MSDN talking about Cross-page posting.
I never worked with Page.PreviousPage. But I think its interesting.
Do you use it? Is it a good pratice, or a bad idea?
What do you think about?
Thanks.
The cross page posting is a helper to post some data to a different page and still have the asp.net code behind functionality.
Why is this exist ? because asp.net have a limitation of one and only form per page. But actually to an html page you can have many forms and many different post to different pages.
So to give a tool to that case, is let you set a second page to post the data, and you setup this on the Button (and not by placing second form), and from there is solve this issue, to post the data to a different page.
For example... with out asp.net and with simple html on a page you can do that.
<body>
<form method="post" action="samepage.html">
Username: <input type="text" name="user" />
<input type="submit" value="Submit" />
</form>
<form method="post" action="page_b.html">
email for news letter: <input type="text" name="email" />
<input type="submit" value="Submit" />
</form>
</body>
To solve a situation like this, and because asp.net not allow two forms at the same page, gives this option.
<body>
<form id="form1" runat="server">
Username: <asp:TextBox runat="server" ID="Name" />
<asp:Button runat="server"/>
email for news letter: <asp:TextBox runat="server" ID="email" />
<asp:Button runat="server" PostBackUrl="page_b.aspx" />
</form>
</body>
In the second case, you have one form, but you set the PostBackUrl to a different page, and from there asp.net still handle the data on code behind direct on a second page (with out redirect).
I hope this example gives you and an idea where to really use the previous page. Also what is more usually is the Redirect, how ever there are case that you need to have the result to a different page. So its per case if you use it or not.
I have an html page that I am converting over to an asp .net page. This page contained a form that accesses an external website that I have no control over. There is some sample code below:
<asp:Content ID="sample" ContentPlaceHolderID="body" Runat="Server">
<form name="Subscribe" method="post" action="http://anexternalwebsitehere.com/subscribe.asp">
<input type="text" name="email" size="45" maxlength="120" />
<input type="submit" name="submit" value="Subscribe" />
</form>
</asp:Content>
The form is more complicated than the example I have provided, but it gives a rough idea of what i need to convert over. Here are the problems I have encountered.
If I leave it as is:
When you click on the submit button you have a postback to the current page and not to the external page
If simply convert everything over to be asp form controls and change the postback url:
The id's become some convoluted "ctl00_body_ctl00" which the external page is not able to interpret.
Note: I do need the page to be an aspx page because I am using a master page for other content on the page.
Additional note: this is not Microsoft MVC.
What am I missing?
The issue was with nested forms as others have mentioned.
I was able to fix all my issues by simply doing the following:
Remove the extra form element i was adding.
Leave all controls as simply html controls, except for the submit button.
Replace the submit button with an asp .net button, and set the postback url.
The old code is as follows:
<asp:Content ID="sample" ContentPlaceHolderID="body" Runat="Server">
<form name="Subscribe" method="post" action="http://anexternalwebsitehere.com/subscribe.asp">
<input type="text" name="email" size="45" maxlength="120" />
<input type="submit" name="submit" value="Subscribe" />
</form>
</asp:Content>
The new code:
<asp:Content ID="sample" ContentPlaceHolderID="body" Runat="Server">
<input type="text" name="email" size="45" maxlength="120" />
<input type="submit" name="submit" value="Subscribe" />
<asp:button postbackurl="http://anexternalwebsitehere.com/subscribe.asp" text="Subscribe" runat="server" />
</asp:Content>
This fixes any of the issues with invalid nested forms as there are none. It also addresses the issue of asp .net renaming the asp elements because the only control that is being renamed is the asp button control which was not necessary for the submission to succeed.
Since you probably have the server form tag on your masterpage spanning your contentplaceholder, this new form you're declaring will be placed inside the server-form (by server-form i mean the one asp.net use for postbacks with runat="server")
I've had cases when i needed a special non-server form on an aspx page that already had a server-form, and the way i solved the problem was to place this non-server form outside the server-form - what i mean is, place it after the server-form. Since you use masterpages, you will need a new contentplaceholder on that masterpage, you can call it "noform". It is placed after the server-form so any content put in this noform will be placed outside the server-form. This mean no asp.net controls will work in this specific contentplaceholder (noform) since they won't be picked up by the framework, but you will be able to place your non-server form there and do your magic on that.
The problem, as you've probably guessed, is that you've got one form inside another form - ie the legacy form is appearing inside the ASP.NET form required by the master page.
One quick (if rather clunky) way to get around this is to close the ASP.NET form above the legacy form, and then open a new form below the legacy form. This means you've got three forms on the page, none of which are nested.
So you end up with something like this:
<asp:Content ID="sample" ContentPlaceHolderID="body" Runat="Server">
</form>
<form name="Subscribe" method="post" action="http://anexternalwebsitehere.com/subscribe.asp">
<input type="text" name="email" size="45" maxlength="120" />
<input type="submit" name="submit" value="Subscribe" />
</form>
<form method="post" action="myAspNetPage.aspx">
</asp:Content>
The closing </form> tag at the start closes the ASP.NET from the master page. You then have your form, which should now work as expected. Then the open <form> tag at the end simply ensures that the closing </form> tag from the master page is valid HTML.
Obviously anything appearing on the master page after the legacy form won't be within the standard ASP.NET form, so this may not work for you depending on how the rest of your page is structured.
It's not a particularly elegant solution, but it works as a quick fix (depending on what else is on your master page). We've used it where we had one legacy form required on a site with hundreds of pages, so we simply wanted a one-off fix rather than anything that affected the master page itself.
In our case, we couldn't change the legacy form as this was supplied by a third-party, regularly changed, and needed to be dropped into the ASP.NET page without a developer getting involved to amend it (eg as opposed to Brian's solution to his own question which requires editing the form and is clearly a better option in his case - and probably in most other cases where there is a similar problem).
Your button's click event will handle submission of the url and data.
//C# source
protected void button_Click(object sender, EventArgs e)
}
string customURL = "http://anexternalwebsitehere.com/";
string emailValue = textBoxEmail.Text; //of course validate this for proper email...
customURL += "page.aspx?email=" + emailValue;
Response.Redirect(customURL);
}