What is a hidden field in ASP.NET Web Forms?
In ASP.NET Web Forms, a hidden field is a special type of input control that allows you to store data on a web page without displaying it to the user. It is typically used to store information that needs to be preserved across postbacks, which are the server round trips that occur when a user interacts with a web form.
Hidden fields are rendered as HTML input elements with the type attribute set to "hidden". They are included within the HTML form tag and can be accessed on the server-side during postback events.
Here's an example of how a hidden field is defined in ASP.NET Web Forms:
<asp:HiddenField ID="hiddenField1" runat="server" Value="SomeValue" />
In the above code snippet, the HiddenField control is defined with an ID attribute and a Value attribute. The ID attribute is used to uniquely identify the hidden field on the server-side, and the Value attribute sets the initial value of the hidden field.
You can access the value of the hidden field on the server-side code-behind file using the HiddenField control's Value property. For example:
string hiddenFieldValue = hiddenField1.Value;
Hidden fields are commonly used to store data that is needed for processing on the server-side but should not be visible or modifiable by the user. This can include things like session identifiers, security tokens, or any other data that needs to persist across multiple requests without being displayed on the page.