Create a Client-Side UI Automation Provider

Create a Client-Side UI Automation Provider

 
System_CAPS_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.

Example

The following example code can be built into a dynamic-link library (DLL) that implements a very simple client-side 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 assembly that can be registered by a UI Automation client application.

using System;
using System.Windows.Automation;
using System.Windows.Automation.Provider;

namespace ClientSideProviderAssembly
{
    // The assembly must implement a UIAutomationClientSideProviders class, 
    // and the namespace must be the same as the name of the DLL, so that 
    // UI Automation can find the table of descriptors. In this example, 
    // the DLL would be "ClientSideProviderAssembly.dll"

    static 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.
                    new ClientSideProviderFactoryCallback(ConsoleProvider.Create),   
                    // Class of window that will be served by the provider.
                    "ConsoleWindowClass")                                                
            };
    }

    class ConsoleProvider : IRawElementProviderSimple
    {
        IntPtr providerHwnd;

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

        internal static IRawElementProviderSimple Create(
            IntPtr hwnd, int idChild, int idObject)
        {
            // This provider doesn't expose children, so never expects 
            // nonzero values for idChild.
            if (idChild != 0)
                return null;
            else
                return new ConsoleProvider(hwnd);

        }

        private static IRawElementProviderSimple Create(
            IntPtr hwnd, int idChild)
        {
            // Something is wrong if idChild is not 0.
            if (idChild != 0) return null;
            else return new ConsoleProvider(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 propertyId)
        {
            if (propertyId == AutomationElementIdentifiers.NameProperty.Id)
                return "Custom Console Window";
            else
                return null;

        }

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