Which interface you will use to wrap an Ajax client control into a custom server control

In ASP.NET, you would typically use the `IScriptControl` interface to wrap an Ajax client control into a custom server control. This interface defines the methods and properties that a server control must implement to support client-side script registration and rendering.

To use this interface, you would create a class that inherits from a server control, and implement the `IScriptControl` interface. This would allow you to register client-side script references, and to render the client-side code for your control.

Here's an example of how you might implement this interface:

using System.Web.UI;

using System.Web.UI.WebControls;

public class MyCustomControl : WebControl, IScriptControl

{

    // Implement the IScriptControl interface

    public IEnumerable<ScriptDescriptor> GetScriptDescriptors()

    {

        // Create a new script descriptor for your control

        ScriptControlDescriptor descriptor = new ScriptControlDescriptor("MyCustomControl", this.ClientID);

        // Add any properties you want to expose to client-side code

        descriptor.AddProperty("SomeProperty", this.SomeProperty);

        // Return the descriptor

        return new ScriptDescriptor[] { descriptor };

    }

    public IEnumerable<ScriptReference> GetScriptReferences()

    {

        // Add any script references that your control needs

        return new ScriptReference[] {

            new ScriptReference("~/MyCustomControl.js")

        };

    }

    // Render the client-side code for your control

    protected override void OnPreRender(EventArgs e)

    {

        // Call the base implementation of OnPreRender

        base.OnPreRender(e);

        // Register the script resources for your control

        ScriptManager.GetCurrent(this.Page).RegisterScriptControl(this);

        // Render the client-side code for your control

        this.Page.ClientScript.RegisterClientScriptResource(

            typeof(MyCustomControl), "MyCustomControl.js");

    }

}

In this example, we define a custom server control called `MyCustomControl` that implements the `IScriptControl` interface. We then implement the two methods required by this interface: `GetScriptDescriptors()` and `GetScriptReferences()`. These methods allow us to specify the script descriptors and script references that our control needs.

In the `OnPreRender()` method, we register the script control with the `ScriptManager` so that it can be added to the page's script resources. We also render the client-side code for the control by calling `RegisterClientScriptResource()`. This method takes the type of our control as the first parameter, and the name of the JavaScript file as the second parameter. This JavaScript file should contain the client-side code for our control.