How can I append the incoming strings of a serial port to a text box?

Question

I am a c# sharp beginner and my first project is a terminal application for the serial port. The incoming data are ascii characters and they come with 115 kbaud.

Now I want to bind each incoming line to a wpf text box. In my serial port class I use IPropertyChanged events and I succeeded in binding each incoming line to the textbox. But it's not satisfying just to see one line, the content of the textbox should be appended with each incoming line. I don't want to collect the strings in my serial port class and just send them all again with each new one. I tried and the result was very slow.

Next I tried to use the binding event TargetUpdated to use textbox.AppendText(incomingline)...

<TextBox 
Name="textBoxIncoming" 
Text="{Binding Path=Incoming, Mode=OneWay, NotifyOnTargetUpdated=True}" 
DataContext="{Binding NotifyOnTargetUpdated=True}"
IsReadOnly="True"
TargetUpdated="textBoxIncoming_TargetUpdated" 
... />`

The result was that each incoming line is displayed twice in the text box, the lines before are cleared.

Does anybody know, how to append text to a textbox with wpf binding?

Answer 1

This cannot be done with a binding alone. Instead, create a List where you add all lines that you receive. Modify the Incoming property to return string.Join(Environment.NewLine, listOfReceivedStrings).