I do not know why but it always enters two new lines:

private void getMyIPAddress()
{
    String Address = "";
    this.Dispatcher.Invoke(() =>
    {
        this.RichTextBox_logs.VerticalScrollBarVisibility = ScrollBarVisibility.Visible;
    });
    while (true)
    {
        this.Dispatcher.Invoke(() =>
        {
            this.RichTextBox_logs.AppendText(Environment.NewLine);
            
            //this.RichTextBox_logs.ScrollToEnd();
        });
        WebRequest request = WebRequest.Create("http://checkip.dyndns.com/");
        try
        {
            using (WebResponse response = request.GetResponse())
            {
                using (StreamReader stream = new StreamReader(response.GetResponseStream()))
                {
                    Address = stream.ReadToEnd();
                }
                int first = Address.IndexOf("Address: ")   9;
                int last = Address.IndexOf("</body>");               

                if (CurrentAddressHolder != Address.Substring(first, last - first))
                {
                    CurrentAddressHolder = Address.Substring(first, last - first);

                    this.Dispatcher.Invoke(() =>
                    {
                        this.textBox_ip.Text = CurrentAddressHolder;
                    });
                    
                }

                this.Dispatcher.Invoke(() =>
                {
                    this.RichTextBox_logs.AppendText("IP is "   CurrentAddressHolder);
                });
            }
        }
        catch(Exception e)
        {
            this.Dispatcher.Invoke(() =>
            {
                this.RichTextBox_logs.AppendText(e.ToString());
            });
        }
    }
}

I'm new to multi-threading and I'm not sure if it affected the syntax to the new line.

Any inputs or code revisions/improvements are highly welcomed. Thanks.

CodePudding user response：

Seems like your problem is line spacing.

Solution one:

Instead of the AppendText() method use the following method to add a text line to the RichTextBox:

public void AddText(RichTextBox rtb, string message, double spacing = 4)
{
    var paragraph = new Paragraph() { LineHeight = spacing };
    paragraph.Inlines.Add(new Run(message));
    rtb.Document.Blocks.Add(paragraph);
}

With this method you will able to change line spacing between paragraphs programmatically by setting the LineHeight value.

When using this approach don't necessary to add the Environment.NewLine. Each block (paragraph) will automatically formatted as different line.

Solution two:

Try to change the paragraph margin (see the following post https://stackoverflow.com/a/445897/6630084):

<RichTextBox x:Name="RichTextBox_logs" >
    <RichTextBox.Resources>
        <Style TargetType="{x:Type Paragraph}">
            <Setter Property="Margin" Value="0"/>
        </Style>
    </RichTextBox.Resources>
    ...
<RichTextBox>