Develop Reference

ASP.net - How to reference a text box in the code behind?

This is highly likely to be a stupid question, so my apologies. But I can't seem to find an answer anywhere. I am brand new to ASP.net and I'm using C# for the code behind (I have experience with C# from a WinForms project I did, also in Visual Studio)
I have a page, a register for an account page, on the website and I want to be able to access the TextBox that contains email and password etc. I thought it would be something like textboxname.getText() or similar to get what the user has typed into that box when they press submit (clicking submit is my Event) but I don't now how to make it recognize that textboxname is the ID.
For example:
<input type="email" class="form-control" placeholder="Enter Email" id="email"/>
My email TextBox has an ID of 'email'. In code, if I try to type email.getText(), it does not recognize that email refers to that TextBox. If I could even get it to recognize the ID, I could figure out the rest from there.
Thank you for listening to my excessive beginner ranting! If any extra details are necessary I'll add them, just ask.
Resolved! - For some reason it did not generate a designer for my pages when i created the web forms, so i regenerated the design.cs and it is working! :D Thanks for help anyway!

Be sure your markup is correct on front end - even if you are a space off between quotes it can mess things up.
<asp:TextBox id="email" runat="server" Text="Email" />
email.Text = "your text here";

You should use email.Text; (since it's a property, no a method) instead of email.getText(). Also make sure your control has runat property equals to "server" on HTML.

On your page
you have to declare a form with a submit button and within this form you can have your textbox.
<form id="myForm" runat="server">
<asp:TextBox id="TB_Email" placeholder="Enter Email" runat="server"></asp:TextBox>
<asp:Button ID="Btn_Submit" runat="server" Text="Submit" OnClick="Btn_Submit_Click" />
</form>
Code behind
protected void Btn_Submit_Click(object sender, EventArgs e)
{
// here you can access the value of your email-textbox
String email = TB_Email.Text;
}

Use:
<input type="email" class="form-control" placeholder="Enter Email" id="email" runat="server"/>
or alternatively,
<asp:TextBox id="email" runat="server"/> /*Add any other attributes you need*/
In the code behind:
email.Text="your text here";
Without runat="server" attribute, your control is just a HTML control and hence you cannot access it from the server side code(code behind).

prevent Asp.NET button from submitting form

So, I have a Paypal form that worked wonders. However, I now need to add a coupon field, where someone can enter a code, and get a reduction based on whatever the backend replies.
This all works wonderfully, but I've ran into an issue when adding the option to know before checking out whether your code is valid or not. Currently, my form (once simplified) looks like this :
<form action="https://www.sandbox.paypal.com/cgi-bin/webscr" method="post"
id="payPalForm" runat="server">
<asp:TextBox runat="server" ID="txtCode" />
<asp:Button Text="Validate" OnClick="ValidateDiscount" runat="server" />
<asp:Label ID="txtDesc" runat="server" />
<input type="submit" name="Submit" value="Pay up!" />
<input type="hidden" name="cmd" value="_cart" />
<input type="hidden" name="upload" value="1" />
...
</form>
With the backend having the function :
protected void ValidateDiscount(object sender, EventArgs e)
{
this.txtDesc.Text = "fetch from database using: " + txtCode.Text;
}
My issue is that wheneve I click on the Validate button, the form is submitted and I end up on the Paypal website. I used Jquery at first with preventDefault(), but that actually prevents my server-side function from firing. I've also tried putting a standard <button> or <input type='button'> tag instead, but I couldn't get it to fire my server-side function.
Is there any way to have the Validate button not submit the form, or should I just remove the action from the form and manually submit the form when clicking on the submit button?

You have set your form action to post to PayPal.
This is the action:
action="https://www.sandbox.paypal.com/cgi-bin/webscr"
Here is where you have it in you form tag:
<form action="https://www.sandbox.paypal.com/cgi-bin/webscr" method="post"
id="payPalForm" runat="server">
Remove this from your form tag and it should postback to your application.

Browser Remember password set username to other textboxes also

When I use browser remembered password, after login, some textboxes in my forms shows username.
I am confused, how it works?
Please provide solution to avoid this problem?

Set TextBox property TextMode as Password
or try this
TextBox1.Attributes.Add("autocomplete", "off");
<form id="Form1" method="post" runat="server" autocomplete="off"></form>
Using Javascript you can also delete history of textbox
function disableautocompletion(id){
var passwordControl = document.getElementById(id);
passwordControl.setAttribute("autocomplete", "off");
}
Try:
<asp:TextBox ID="MyTextBox" AutoCompleteType="Disabled" runat="server" />
this renders as:
<input id="MyTextBox" name="MyTextBox" type="text" autocomplete="off" />
for more info MSDN for autocomplete
And this is helpful link

ASP.NET - Using SagePay Form Method Within a Content Page

I have an ASP.NET site and need to post some hidden form fields to SagePay so that my customers can pay for goods. I am using the following method to do this:
<input type="hidden" name="VPSProtocol" value="2.23" />
<input type="hidden" name="Currency" value="gbp" />
<input type="hidden" name="TxType" value="PAYMENT" />
<input type="hidden" name="Vendor" value="myvendorname" />
<input type="hidden" runat="server" id="crypt" name="Crypt" value="#<encrypted string>" />
<asp:Button ID="Button1" runat="server" Text="Pay Now" PostBackUrl="https://live.sagepay.com/gateway/service/vspform-register.vsp"/>
Now, If I use this code in a standard ASP.NET form, this works fine - SagePay accepts the posted information and continues with the payment process. However, if I use the same code inside a content page with a master page, Sagepay displays the following error screen:
5030 : We could not process your message, please check your
integration settings or contact the support team.
It seems as if the hidden fields are losing their value because of the master page.
Could anyone tell me what could be happening here and if there is anything I can do to rectify the situation. I need to use the SagePay Form method and I need to use a masterpage.

I haven't used webforms for a while but from memory by default it changes the names of your elements based on their container to allow navigation and identification server side: MSDN documentation here.
This means that your posted values are not under the name you expect them to be.

ASP (.NET 4) ViewState enabled Literal control not retaining changes to HTML contents on PostBack

I am populating a ListView with HTML from a database using a Literal with Text='<%#Eval("HTMLData")'%>. When I trigger a PostBack, changes to the loaded HTML are not being reflected in litRowData.Text.
ViewState is enabled for the page, the ListView, and the Literal in the ItemTemplate, and I am making sure to only populate the ListView with initial values from the database when if(!IsPostBack) is true in Page_Load.
<asp:ListView ID="lvForm" runat="server"
DataKeyNames="RowID" ItemPlaceholderID="phRow"
EnableViewState="true">
<LayoutTemplate>
<asp:PlaceHolder ID="phRow" runat="server" />
</LayoutTemplate>
<ItemTemplate>
<asp:Literal ID="litRowData" runat="server" Text='<%#Eval("HTMLData")%>'
EnableViewState="true"></asp:Literal>
</ItemTemplate>
</asp:ListView>
I need to be able to capture changes to the contents of the loaded HTML controls. Since this HTML comes from a database table, I can't just use ASP controls inside the ItemTemplate. Can anyone see something I'm missing, or suggest an alternative way to do this?
Edit:
To clarify a little more, I'm trying to load form input elements dynamically from a database, render them as HTML controls on the page, allow the user to modify their contents by entering text or selecting options, then capture the modified HTML and save it back to the database when the user clicks a save button.

The way postback works in .NET is actually a wrapper around the more basic idea of HTML forms. A basic example of HTML forms is:
<html>
<body>
<form action="" method="POST">
<input type="text" value="type here" />
<input type="submit" value="go" />
</form>
</body>
</html>
Roughly, what the .NET abstraction adds is:
<html>
<body>
<form action="" method="POST">
<input type="hidden" name="__VIEWSTATE" value="string-encoded-value" />
<input type="text" name="bob" value="type here" />
<input type="submit" value="go" />
</form>
</body>
</html>
Whereby on postback to your page, all input elements with names are mapped back into properties of your Page object, and the __VIEWSTATE hidden field is deserialized into all properties of objects that do not correspond to values of html input tags. For example, if Page.bob had a DateTime property associated with it, it would be stored in __VIEWSTATE possibly.
ASP.NET Literal tags in Page markup will get printed into the browser exactly as is, meaning that if you have <span>bob</span> as its value, that is how it will appear within the <form> tag. However, in plain HTML world, <form> tags when posted will only contain the values of certain form elements (aka not every div, span, p etc. gets posted back, only input, select, textarea and some others). So if your literal doesn't contain an input then it won't even get posted back meaning __VIEWSTATE will be used to restore the Value property of the Literal back to its initial state.
To fix this, you probably don't want to stick html into a Literal because even if you do it's not clear that it will get associated with the right property of your page. Instead, try a TextBox element or something else that gets written as an input element directly by the ASP.NET webforms code. Alternatively, try using javascript to allow modifications of flat text in divs if you don't need to persist the data.

This answer builds on the prior one now that you have a .NET TextBox control that is correctly posting back the value of edits. Right below it, you can add to code behind:
protected void Page_Load(object sender, EventArgs e)
{
litRowData.Attributes.Add("onKeyUp", "WriteText(this.value)");
}
Html:
<ItemTemplate>
<asp:TextBox ID="litRowData" runat="server" />
</ItemTemplate>
<div id="yourPreview"></div>
<script type="text/javascript">
function WriteText(val){
document.getElementById("yourPreview").innerHTML=val
}
</script>