So I am trying to gett all the open tabs from Chrome using UIAutomation in C# but I keep getting the error:
System.ArgumentNullException occurred
HResult=0x80004003
Message=Value can't be NULL.
Source=UIAutomationClientStackTrace:
at System.Windows.Automation.TreeWalker.GetParent(AutomationElement element)
at chromeTabsTest.Program.Main(String[] args) in C:\Users...\chromeTabsTest\chromeTabsTest\Program.cs:line 31
The error is indicated with a comment in the code.
using System;
using System.Diagnostics;
using System.Windows.Automation;
namespace chromeTabsTest
{
class Program
{
static void Main(string[] args)
{
Process[] procsChrome = Process.GetProcessesByName("chrome");
if (procsChrome.Length <= 0)
{
Console.WriteLine("Chrome is not running");
}
else
{
foreach (Process proc in procsChrome)
{
// the chrome process must have a window
if (proc.MainWindowHandle == IntPtr.Zero)
{
continue;
}
// to find the tabs we first need to locate something reliable - the 'New Tab' button
AutomationElement root = AutomationElement.FromHandle(proc.MainWindowHandle);
Condition condNewTab = new PropertyCondition(AutomationElement.NameProperty, "New Tab");
AutomationElement elmNewTab = root.FindFirst(TreeScope.Descendants, condNewTab);
// get the tabstrip by getting the parent of the 'new tab' button
TreeWalker treewalker = TreeWalker.ControlViewWalker;
AutomationElement elmTabStrip = treewalker.GetParent(elmNewTab); // <------------- Error here
// loop through all the tabs and get the names which is the page title
Condition condTabItem = new PropertyCondition(AutomationElement.ControlTypeProperty, ControlType.TabItem);
foreach (AutomationElement tabitem in elmTabStrip.FindAll(TreeScope.Children, condTabItem))
{
Console.WriteLine(tabitem.Current.Name);
}
}
}
Console.Write("\nPress any key to continue...");
Console.ReadKey();
}
}
}
This code is from another Stack Overflow question: question
It seems that the following line is language sensitive:
Condition condNewTab = new PropertyCondition(AutomationElement.NameProperty, "New Tab");
That is to say that "New Tab" rather than being an internal field is a localised string. This means that this line must be updated to have the correctly localised version of this text.
It is quite possible that there is a better "locate something reliable" that could be used but I am not familiar enough with chrome automation to be able to say if there is and if so what.
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