How to focus two text boxes at a time?

Question

Hi,
I am developing a packet analyzer software. In that, I need to focus two text boxes as I select a treeview item.
I am using a following code:
delegate void voiDelegate();
private void click(object sender, RoutedPropertyChangedEventArgs<object> e)
TreeViewItem t;
t =(TreeViewItem) tvMain.SelectedItem;
StackPanel s = (StackPanel)t.Header;
List<TextBlock> l = new List<TextBlock>(3);
foreach (TextBlock children in s.Children)
l.Add(children);
string ch = l[3].Text;
string[] sp = ch.Split('-');
int te = Convert.ToByte(sp[1]) - Convert.ToByte(sp[0]) + 1;
PacketDisplay1.SelectionStart = PacketDisplay2.SelectionStart = Convert.ToByte(sp[0]);
PacketDisplay1.SelectionLength= PacketDisplay2.SelectionLength = te;
voiDelegate giveFocusDelegate = new voiDelegate(giveFocus);
Dispatcher.BeginInvoke(giveFocusDelegate, new object[] { });
private void giveFocus()
PacketDisplay1.Focus();
PacketDisplay2.Focus();
but here I am able to focus only on second Textbox. I need to focus on both textboxes. How can I achieve this?
My requirement is like this
thank you.

Answer 1

The documentation is pretty clear on this: There can be only one
element on the whole desktop that has keyboard focus:
https://msdn.microsoft.com/en-us/library/aa969768%28v=vs.110%29.aspx?f=255&MSPPError=-2147217396.
There is logical focus and there is keyboard focus. There can be multiple elements that have logical focus in an application but only a single element can have keyboard focus. Please refer to the link above for details.
If you want to highlight text in two different TextBoxes at the same time, you could replace the TextBox elements with RichTextBox elements, and set the background of a text range. Please refer to the following thread for more information about how you could
do this:
http://stackoverflow.com/questions/18015380/how-can-i-change-the-selected-text-background-color-in-rich-text-box-wpf-c-sharp
Here is an example for you:
public partial class Window6 : Window
private static TextPointer GetTextPointAt(TextPointer from, int pos)
TextPointer ret = from;
int i = 0;
while ((i < pos) && (ret != null))
if ((ret.GetPointerContext(LogicalDirection.Backward) == TextPointerContext.Text) || (ret.GetPointerContext(LogicalDirection.Backward) == TextPointerContext.None))
i++;
if (ret.GetPositionAtOffset(1, LogicalDirection.Forward) == null)
return ret;
ret = ret.GetPositionAtOffset(1, LogicalDirection.Forward);
return ret;
internal string Select(RichTextBox rtb, int offset, int length, Color color)
// Get text selection:
TextSelection textRange = rtb.Selection;
// Get text starting point:
TextPointer start = rtb.Document.ContentStart;
// Get begin and end requested:
TextPointer startPos = GetTextPointAt(start, offset);
TextPointer endPos = GetTextPointAt(start, offset + length);
// New selection of text:
textRange.Select(startPos, endPos);
// Apply property to the selection:
textRange.ApplyPropertyValue(TextElement.BackgroundProperty, new SolidColorBrush(color));
// Return selection text:
return rtb.Selection.Text;
public Window6()
InitializeComponent();
//set text
PacketDisplay1.Document.Blocks.Clear();
PacketDisplay1.Document.Blocks.Add(new Paragraph(new Run("some text....")));
PacketDisplay2.Document.Blocks.Clear();
PacketDisplay2.Document.Blocks.Add(new Paragraph(new Run("some other text....")));
//set background
this.Select(this.PacketDisplay1, 0, 4, SystemColors.HighlightBrush.Color); //select "some"
this.Select(this.PacketDisplay2, 0, 4, SystemColors.HighlightBrush.Color); //select "some"
There is no way to achieve this by simply selecting text in two different TextBoxes and there is no way to set the background of a text range in a ordinary TextBox so you must use a RichTextBox here.
Please remember to close your threads by marking helpful posts as answer and then start a new thread if you have a new question. Please don't ask several questions in the same thread.