FormDigest Class
The FormDigest class inserts a security validation within the form of an .aspx page.
System.Object
System.Web.UI.Control
Microsoft.SharePoint.WebControls.SPControl
Microsoft.SharePoint.WebControls.FormDigest
Public Constructors
The following table shows the public constructors of the FormDigest class and a brief description of each.
| Name | Description |
|---|---|
| FormDigest | Initializes a new instance of the FormDigest class. |
Protected Methods
The following table shows the protected methods of the FormDigest class and a brief description of each.
| Name | Description |
|---|---|
| Render | Sends the content of the control to the specified HtmlTextWriter object, which writes the content that is rendered on the client. |
Public Properties
The following table shows the public properties of the OWSNumberField class, the data type of each property, and a brief description of each.
| Name | Data Type | Description |
|---|---|---|
| DigestValue | String | Gets the value of the security validation that is inserted in the .aspx page. |
Thread Safety
Any public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Any instance members are not guaranteed to be thread safe.
Remarks
To make posts from a Web application that modify the contents of the database, you must include the FormDigest control in the form making the post. The FormDigest control generates a security validation, or message digest, to help prevent the type of attack whereby a user is tricked into posting data to the server without knowing it. The security validation is specific to a user, site, and time period and expires after a configurable amount of time. When the user requests a page, the server returns the page with security validation inserted. When the user then submits the form, the server verifies that the security validation has not changed.
For more information on security validation, see Security Validation and Making Posts to Update Data.
Example
The following code example shows a form that contains the FormDigest control.
<form id="Form1" method="post" >
<SharePoint:FormDigest />
<asp:Button id="Button1" style="Z-INDEX: 101; LEFT: 282px; POSITION: absolute;
TOP: 282px" Text="Button"></asp:Button>
</form>
Requirements
Namespace: Microsoft.SharePoint.WebControls
Platforms: Microsoft Windows Server 2003
Assembly: Windows SharePoint Services (in Microsoft.SharePoint.dll)
Security: Code Access Security