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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
)

Parameters

hiddenFieldName
Type: System.String

The name of the hidden field to register.

hiddenFieldInitialValue
Type: System.String

The initial value of the field to register.

ExceptionCondition
ArgumentNullException

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"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<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));} </");
      cstext.Append("script>");
      cs.RegisterClientScriptBlock(cstype, csname, cstext.ToString(), false);
    }
  }
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head>
    <title>ClientScriptManager Example</title>
  </head>
  <body>
     <form    id="Form1"
            runat="server">
     <input type="text"
            id="Message" />
     <input type="button" 
            onclick="DoClick()" 
            value="Run Script" />
     </form>
  </body>
</html>

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

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