How to write into a WPF textbox in another WPF app form?

Question

With any non-WPF forms, we can use WindowFromPoint and FindWindow etc to get a HWND of any target and SendMessage to write or click. How to achieve the same with WPF form? 

Answer 1

Hi,

you could use UIAutomation:

http://msdn.microsoft.com/en-us/library/system.windows.automation.peers.aspx

Here is an example for UIAutomation I recently experimented with:

Imports System.Windows.Automation
Imports System.Windows.Automation.Peers
Imports System.Windows.Automation.AutomationElement
Imports System.Windows.Automation.TreeWalker
Imports System.Windows.Automation.Provider

...

  ' Open Windows Start using UIAutomation:
  Private Sub btWindowStart_Click(ByVal sender As Object, ByVal e As System.Windows.RoutedEventArgs) Handles btWindowStart.Click

    Dim element As AutomationElement = _
      AutomationElement.RootElement.FindFirst(TreeScope.Descendants, _
                                              New AndCondition(New PropertyCondition(AutomationElement.ControlTypeProperty, _
                                                                                     ControlType.Button), _
                                              New PropertyCondition(AutomationElement.NameProperty, "Start", _
                                                                    PropertyConditionFlags.IgnoreCase)))

    Dim patty As InvokePattern = element.GetCurrentPattern(InvokePattern.Pattern)
    Try
      patty.Invoke()
    Catch ex As Exception
      MessageBox.Show(ex.Message.ToString)
    End Try

  End Sub

...

  ' This Button will be invoked using UIAutomation whithin the same WPF Application
  Private Sub btAutomationTarget_Click(ByVal sender As Object, _
                                       ByVal e As System.Windows.RoutedEventArgs) _
                                       Handles btAutomationTarget.Click

    MessageBox.Show("I have been automated!")

  End Sub

  ' Here I invoke the above Button using UIAutomation
  Private Sub btAutomate_Click(ByVal sender As Object, _
                               ByVal e As System.Windows.RoutedEventArgs) _
                               Handles btAutomate.Click

    Dim peer As New ButtonAutomationPeer(btAutomationTarget)
    Dim invokeProv As IInvokeProvider = peer.GetPattern(PatternInterface.Invoke)
    invokeProv.Invoke()

  End Sub

There is a special class to expose TextBox types to UIAutomation:

http://msdn.microsoft.com/en-us/library/system.windows.automation.peers.textboxautomationpeer.aspx

Instead of using the RootElement property as the starting point for the TreeScope to locate the instance of the desired AutomationElement you could use the property FocusedElement, or the methods FromHandle or FromPoint.

Here is an example for the usage of the method FromHandle:

  Private Sub blob()

    Dim _handle As IntPtr = New WindowInteropHelper(Application.Current.MainWindow).Handle

    Dim windowElt As AutomationElement = AutomationElement.FromHandle(_handle)

    ' ...

  End Sub

If you use UIAutomation you should take care not to block the UI thread. So you should code the automation calls in a seperate thread if you locate a AutomationElement from RootElement as starting point.

Best regards,
M.

Answer 2

hey, this is really cool and powerful! It can also write on web pages, wpf, and windows native. I tested the following code, and it writes on textbox anywhere.

 

private void pictureBox1_MouseUp(object sender, MouseEventArgs e)

{

pictureBox1.Load(

@"..\..\app_cross.bmp");
System.Windows.Point p = new System.Windows.Point();
p.X = MousePosition.X;
p.Y = MousePosition.Y;
AutomationElement element = AutomationElement.FromPoint(p);
ValuePattern textcontrol = (ValuePattern)element.GetCurrentPattern(ValuePattern.Pattern);
textcontrol.SetValue(textBox1.Text);

}

Thank you!