How to add a focus to an editable ComboBox in WPF

Question

I am using an editable ComboBox in wpf but when i try to set focus from C# code, it is only shows selection. but i want to go for edit option (cursor should display for user

Answer 1

Based on the answer of user128300 above I came up with a slightly simpler solution. In the constructor or ContextChangedHandler the code is waiting for the control to be loaded before putting the focus on the UI element

myComboBox.GotFocus += MyComboBoxGotFocus;
myComboBox.Loaded += (o, args) => { myComboBox.Focus(); };

Then in the focus even handler I select all the text from the start to the end

private void MyComboBoxGotFocus(object sender, RoutedEventArgs e)
{
    var textBox = myComboBox.Template.FindName("PART_EditableTextBox", myComboBox) as TextBox;
    if (textBox != null)
        textBox.Select(0, textBox.Text.Length);
}

In xaml the combobox is editable. By selecting all the text when user type a key it is resetting the previous value