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ClientScriptManager.RegisterHiddenField Method

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.


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" />

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0