ScriptManager.RegisterExpandoAttribute Method (Control, String, String, String, Boolean)


The .NET API Reference documentation has a new home. Visit the .NET API Browser on to see the new experience.

Registers a name/value pair with the ScriptManager control as a custom (expando) attribute of a specified control.

Namespace:   System.Web.UI
Assembly:  System.Web.Extensions (in System.Web.Extensions.dll)

public static void RegisterExpandoAttribute(
	Control control,
	string controlId,
	string attributeName,
	string attributeValue,
	bool encode


Type: System.Web.UI.Control

The control that is registering the expando attribute.

Type: System.String

The control that contains the custom attribute on the page.

Type: System.String

The name of the custom attribute to register.

Type: System.String

The value of the custom attribute.

Type: System.Boolean

true to encode the custom attribute that is being registered; otherwise, false.

Exception Condition

control is null.


control is not in the page's control tree.

- or -

controlId is null.

- or -

controlId is empty.

- or -

attributeName is null.

- or -

attributeName is empty.

- or -

attributeName is already registered.

You use the RegisterExpandoAttribute method to register a custom (expando) property for a control that is compatible with partial-page rendering and that has no Microsoft Ajax Library dependencies.

The RegisterExpandoAttribute method registers a name/value pair as a custom attribute for the specified control. The property is set dynamically from ECMAScript (JavaScript) to preserve XHTML compatibility for the rendered control's markup. Set encode to true if you have to escape any characters in the dynamic property's value.

If the control to which the dynamic property will be added is not found, a script error occurs.

.NET Framework
Available since 3.5
Return to top