Page.IsClientScriptBlockRegistered(String) Method

Reference

Definition

Namespace:: System.Web.UI

Assembly:: System.Web.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Caution

The recommended alternative is ClientScript.IsClientScriptBlockRegistered(string key). http://go.microsoft.com/fwlink/?linkid=14202

Determines whether the client script block with the specified key is registered with the page.

public:
 bool IsClientScriptBlockRegistered(System::String ^ key);

public bool IsClientScriptBlockRegistered (string key);

[System.Obsolete("The recommended alternative is ClientScript.IsClientScriptBlockRegistered(string key). http://go.microsoft.com/fwlink/?linkid=14202")]
public bool IsClientScriptBlockRegistered (string key);

member this.IsClientScriptBlockRegistered : string -> bool

[<System.Obsolete("The recommended alternative is ClientScript.IsClientScriptBlockRegistered(string key). http://go.microsoft.com/fwlink/?linkid=14202")>]
member this.IsClientScriptBlockRegistered : string -> bool

Public Function IsClientScriptBlockRegistered (key As String) As Boolean

Parameters

key: String

The string key of the client script to search for.

Returns

Boolean

true if the script block is registered; otherwise, false.

Attributes: ObsoleteAttribute

Examples

The following code example demonstrates the use of the RegisterClientScriptBlock method in conjunction with the IsClientScriptBlockRegistered method. If the ECMAScript written in the code declaration block has not already been registered, as determined by IsClientScriptBlockRegistered, then a RegisterClientScriptBlock call is made.

<%@ 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)
  {
    String csname1 = "PopupScript";
    String csname2 = "ButtonClickScript";

    if (!IsClientScriptBlockRegistered(csname1))
    {
        String cstext1 = "<script type=\"text/javascript\">" +
            "alert('Hello World');</" + "script>";
        RegisterStartupScript(csname1, cstext1);
    }

    if (!IsClientScriptBlockRegistered(csname2))
    {
      StringBuilder cstext2 = new StringBuilder();
      cstext2.Append("<script type=\"text/javascript\"> function DoClick() {");
      cstext2.Append("Form1.Message.value='Text from client script.'} </");
      cstext2.Append("script>");
      RegisterClientScriptBlock(csname2, cstext2.ToString());
    }
  }
</script>
<html  >
  <head>
    <title>RegisterClientScriptBlock Example</title>
  </head>
  <body>
     <form id="Form1"
         runat="server">
        <input type="text" id="Message" /> <input type="button" value="ClickMe" onclick="DoClick()" />
     </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 EventArgs)
        Dim csname1 As String = "PopupScript"

        Dim csname2 As String = "ButtonClickScript"
    
        If Not IsClientScriptBlockRegistered(csname1) Then
            Dim cstext1 As String = "<script type=""text/javascript"">" & _
                "alert('Hello World');</" & "script>"
            RegisterStartupScript(csname1, cstext1)
        End If
    
        If Not IsClientScriptBlockRegistered(csname2) Then
            Dim cstext2 As New StringBuilder()
            cstext2.Append("<script type=""text/javascript""> function DoClick() {")
            cstext2.Append("Form1.Message.value='Text from client script.'} </")
            cstext2.Append("script>")
            RegisterClientScriptBlock(csname2, cstext2.ToString())
        End If
    End Sub
</script>
<html  >
  <head>
    <title>RegisterClientScriptBlock Example</title>
  </head>
  <body>
     <form id="Form1"
         runat="server">
        <input type="text" id="Message" /> <input type="button" value="ClickMe" onclick="DoClick()" />
     </form>
  </body>
</html>

Remarks

Call this method before calling Page.RegisterClientScriptBlock to avoid unnecessarily assembling the client-side script. This is particularly important if the script requires a large amount of server resources to create.

The IsClientScriptBlockRegistered method has been deprecated. Use the IsClientScriptBlockRegistered method in the ClientScriptManager class.

Applies to

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