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Implement UI Automation Providers in a Client Application

NoteNote

This documentation is intended for .NET Framework developers who want to use the managed UI Automation classes defined in the System.Windows.Automation namespace. For the latest information about UI Automation, see Windows Automation API: UI Automation.

This topic contains example code that shows how to implement a client-side UI Automation provider within an application.

This is an uncommon scenario. Most often, a UI Automation client application uses server-side providers, or client-side providers that reside in a DLL.

The following example code implements a simple provider for a console window. The code does not have any useful functionality, but is intended to demonstrate the basic steps in setting up a provider within client code and registering it by using RegisterClientSideProviders.


using System;
using System.Windows.Automation;
using System.Windows.Automation.Provider;
using System.Reflection;
using System.Runtime.InteropServices;    // for DllImport
using System.IO;


namespace CSClientProviderImplementation
{
    class CSClientSideImplementationProgram
    {
        [DllImport("kernel32.dll")]
        static extern IntPtr GetConsoleWindow();


        static void Main(string[] args)
        {

            ClientSettings.RegisterClientSideProviders(
                UIAutomationClientSideProviders.ClientSideProviderDescriptionTable);

            IntPtr hwnd = GetConsoleWindow();

            // Get an AutomationElement that represents the window. 
            AutomationElement elementWindow = AutomationElement.FromHandle(hwnd);
            Console.WriteLine("Found UI Automation client-side provider for:");

            // The name property is furnished by the client-side provider.
            Console.WriteLine(elementWindow.Current.Name);
            Console.WriteLine();

            Console.WriteLine("Press any key to exit.");
            Console.ReadLine();
        }
    }  // CSClientSideImplementationProgram class


    class UIAutomationClientSideProviders
    {
        /// <summary>
        /// Implementation of the static ClientSideProviderDescriptionTable field. 
        /// In this case,only a single provider is listed in the table.
        /// </summary>
        public static ClientSideProviderDescription[] ClientSideProviderDescriptionTable = 
            { new ClientSideProviderDescription(
                // Method that creates the provider object.
                WindowProvider.Create,    
                // Class of window that will be served by the provider.
                "ConsoleWindowClass") };  
    }

    class WindowProvider : IRawElementProviderSimple
    {
        IntPtr providerHwnd;

        public WindowProvider(IntPtr hwnd)
        {
            providerHwnd = hwnd;
        }

        internal static IRawElementProviderSimple Create(
            IntPtr hwnd, int idChild, int idObject)
        {
            return Create(hwnd, idChild);
        }

        private static IRawElementProviderSimple Create(
            IntPtr hwnd, int idChild)
        {
            // Something is wrong if idChild is not 0.
            if (idChild != 0) return null;
            else return new WindowProvider(hwnd);
        }

        #region IRawElementProviderSimple

        // This is a skeleton implementation. The only real functionality at this stage 
        // is to return the name of the element and the host window provider, which can 
        // supply other properties.

        ProviderOptions IRawElementProviderSimple.ProviderOptions
        {
            get
            {
                return ProviderOptions.ClientSideProvider;
            }
        }

        IRawElementProviderSimple IRawElementProviderSimple.HostRawElementProvider
        {
            get
            {
                return AutomationInteropProvider.HostProviderFromHandle(providerHwnd);
            }
        }

        object IRawElementProviderSimple.GetPropertyValue(int aid)
        {
            if (AutomationProperty.LookupById(aid) ==
                AutomationElementIdentifiers.NameProperty)
            {
                return "Custom Console Window";
            }
            else
            {
                return null;
            }

        }

        object IRawElementProviderSimple.GetPatternProvider(int iid)
        {
            return null;
        }
        #endregion IRawElementProviderSimple
    }
}


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