RegisterHiddenField Method

ClientScriptManager.RegisterHiddenField Method (String, String)


Registers a hidden value with the Page object.

Namespace:   System.Web.UI
Assembly:  System.Web (in System.Web.dll)

public void RegisterHiddenField(
	string hiddenFieldName,
	string hiddenFieldInitialValue


Type: System.String

The name of the hidden field to register.

Type: System.String

The initial value of the field to register.

Exception Condition

hiddenFieldName is null.

The RegisterHiddenField method creates a hidden <input> element on the rendered HTML page.

The following code example demonstrates the use of the RegisterArrayDeclaration and RegisterHiddenField methods. The example registers an array and a hidden value and defines the OnClick event of an <input> button to calculate the sum of two values of the array and the hidden value.

<%@ Page Language="C#"%>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
<script runat="server">

  public void Page_Load(Object sender, EventArgs e)
    // Define the array name and values.
    String arrName = "MyArray";
    String arrValue = "\"1\", \"2\", \"text\"";

    // Define the hidden field name and initial value.
    String hiddenName = "MyHiddenField";
    String hiddenValue = "3";

    // Define script name and type.
    String csname = "ConcatScript";
    Type cstype = this.GetType();

    // Get a ClientScriptManager reference from the Page class.
    ClientScriptManager cs = Page.ClientScript;

    // Register the array with the Page class.
    cs.RegisterArrayDeclaration(arrName, arrValue);

    // Register the hidden field with the Page class.
    cs.RegisterHiddenField(hiddenName, hiddenValue);

    // Check to see if the  script is already registered.
    if (!cs.IsClientScriptBlockRegistered(cstype, csname))
      StringBuilder cstext = new StringBuilder();
      cstext.Append("<script type=\"text/javascript\"> function DoClick() {"); 
      cstext.Append("Form1.Message.value='Sum = ' + ");
      cstext.Append("(parseInt(" + arrName + "[0])+");
      cstext.Append("parseInt(" + arrName + "[1])+");
      cstext.Append("parseInt(" + Form1.Name + "." + hiddenName + ".value));} </");
      cs.RegisterClientScriptBlock(cstype, csname, cstext.ToString(), false);
<html xmlns="" >
    <title>ClientScriptManager Example</title>
     <form    id="Form1"
     <input type="text"
            id="Message" />
     <input type="button" 
            value="Run Script" />

.NET Framework
Available since 2.0
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