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Implement UI Automation Providers in a Client Application

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.

Example

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
    }
}

See Also

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