What are Hidden fields in asp.net with example

The hidden field is a control that stores a value but does not display that value to the user. It is like a label that had a value, but was hidden. The hidden field is rendered as an HTML element. The hidden field can be used to store data that needs to persist across multiple post backs. This control can come in handy when other methods of storing data across post backs are not available, such as session states and cookies.

 The data is store on the client side. It store only one value for variable and is saved as string. It is not visible in browser but can see the stored data by using view source operation of the browser. 

  

Source Code:

<fieldset style="width:400px">

    <legend>Hidden Field Explanation</legend>

    <table>

    <tr><td></td><td><asp:HiddenField ID="HiddenField1" runat="server" /></td></tr>

    <tr><td></td><td><asp:Button ID="Button1" runat="server" Text="Button"

            onclick="Button1_Click1" /></td></tr>    

    <tr><td></td><td><asp:Label ID="Label1" runat="server"></asp:Label></td></tr>    

    </table>

    </fieldset>

Write the below given code on .aspx.cs file(C#):

protected void Page_Load(object sender, EventArgs e)

    {

        HiddenField1.Value = "Hidden Field Test";

    }

  

    protected void Button1_Click1(object sender, EventArgs e)

    {

        Label1.Text = HiddenField1.Value;

    }

In VB:

Protected Sub Page_Load(sender As Object, e As System.EventArgs) Handles Me.Load

        HiddenField1.Value = "Hidden Field Test"

    End Sub

    Protected Sub Button1_Click1(sender As Object, e As System.EventArgs) HandlesButton1.Click

        Label1.Text = HiddenField1.Value

    End Sub

Advantages:

   1.   Server resources are not required

   2.    Hidden fields are easy to implement

    3.   All browsers support the hidden filed

4. Useful to retain value between multiple post backs.

Disadvantages:

      1.    Hidden fields are not secure because data is stored on client side.

      2.    Hidden field can store only one value.

      3.   Hidden field slow down the performance of page if use large number of hidden fields