using System;
using System.Text;
using System.Diagnostics;
using System.Threading;
using System.Windows.Automation;

namespace UIATest
{
    class Program
    {
        static void Main(string[] args)
        {
            Process process = Process.Start(@"F:\CSharpDotNet\AutomationTest\ATP\WpfApp\bin\Debug\WpfApp.exe");
            int processId = process.Id;
            AutomationElement element = FindElementById(processId, "comboBox1");
            ExpandCollapsePattern currentPattern = GetExpandCollapsePattern(element);
            currentPattern.Expand();
            Thread.Sleep(1000);
            currentPattern.Collapse();
        }

        /**//// <summary>
        /// Get the automation elemention of current form.
        /// </summary>
        /// <param name="processId">Process Id</param>
        /// <returns>Target element</returns>
        public static AutomationElement FindWindowByProcessId(int processId)
        {
            AutomationElement targetWindow = null;
            int count = 0;
            try
            {
                Process p = Process.GetProcessById(processId);
                targetWindow = AutomationElement.FromHandle(p.MainWindowHandle);
                return targetWindow;
            }
            catch (Exception ex)
            {
                count++;
                StringBuilder sb = new StringBuilder();
                string message = sb.AppendLine(string.Format("Target window is not existing.try #{0}", count)).ToString();
                if (count > 5)
                {
                    throw new InvalidProgramException(message, ex);
                }
                else
                {
                    return FindWindowByProcessId(processId);
                }
            }
        }

        /**//// <summary>
        /// Get the automation element by automation Id.
        /// </summary>
        /// <param name="windowName">Window name</param>
        /// <param name="automationId">Control automation Id</param>
        /// <returns>Automatin element searched by automation Id</returns>
        public static AutomationElement FindElementById(int processId, string automationId)
        {
            AutomationElement aeForm = FindWindowByProcessId(processId);
            AutomationElement tarFindElement = aeForm.FindFirst(TreeScope.Descendants,
            new PropertyCondition(AutomationElement.AutomationIdProperty, automationId));
            return tarFindElement;
        }

        ExpandCollapsePattern helper#region ExpandCollapsePattern helper

        /**//// <summary>
        /// Get ExpandCollapsePattern
        /// </summary>
        /// <param name="element">AutomationElement instance</param>
        /// <returns>ExpandCollapsePattern instance</returns>
        public static ExpandCollapsePattern GetExpandCollapsePattern(AutomationElement element)
        {
            object currentPattern;
            if (!element.TryGetCurrentPattern(ExpandCollapsePattern.Pattern, out currentPattern))
            {
                throw new Exception(string.Format("Element with AutomationId '{0}' and Name '{1}' does not support the ExpandCollapsePattern.",
                    element.Current.AutomationId, element.Current.Name));
            }
            return currentPattern as ExpandCollapsePattern;
        }

        #endregion
    }
　　}