ClientScriptManager.RegisterHiddenField(String, String) Method

Reference

Definition

Namespace:: System.Web.UI

Assembly:: System.Web.dll

Important

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Registers a hidden value with the Page object.

public:
 void RegisterHiddenField(System::String ^ hiddenFieldName, System::String ^ hiddenFieldInitialValue);

public void RegisterHiddenField (string hiddenFieldName, string hiddenFieldInitialValue);

member this.RegisterHiddenField : string * string -> unit

Public Sub RegisterHiddenField (hiddenFieldName As String, hiddenFieldInitialValue As String)

Parameters

hiddenFieldName: String

The name of the hidden field to register.

hiddenFieldInitialValue: String

The initial value of the field to register.

Exceptions

ArgumentNullException

hiddenFieldName is null.

Examples

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>

<%@ Page Language="VB" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">

  Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)

    ' Define the array name and values.
    Dim arrName As String = "MyArray"
    Dim arrValue As String = """1"", ""2"", ""text"""
    
    ' Define the hidden field name and initial value.
    Dim hiddenName As String = "MyHiddenField"
    Dim hiddenValue As String = "3"
    
    ' Define script name and type.
    Dim csname As String = "ConcatScript"
    Dim cstype As Type = Me.GetType()
        
    ' Get a ClientScriptManager reference from the Page class.
    Dim cs As ClientScriptManager = 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 (Not cs.IsClientScriptBlockRegistered(cstype, csname)) Then
      Dim cstext As StringBuilder = 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)
    End If
    
  End Sub
  
</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>

Remarks

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

Applies to