CODEWITHSUNDEEP
c#wpf
Ian
Ian

Reputation: 30813

WPF RichTextBox First Line \n is not Printed

I have a very simple WPF application which only have a RichTextBox and a button declared like this:

<Window x:Class="TestApp.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:SimpleChessWPF"
        mc:Ignorable="d"
        Title="MainWindow" Height="670.8" Width="741.8">
  <Grid>
    <RichTextBox HorizontalAlignment="Left" Height="534" Margin="10,97,0,0" VerticalAlignment="Top" Width="715" Name="TestRtb">
      <RichTextBox.Resources>
        <Style TargetType="{x:Type Paragraph}">
          <Setter Property="Margin" Value="0"/>
        </Style>
      </RichTextBox.Resources>
    </RichTextBox>
    <Button Content="Button" HorizontalAlignment="Left" Margin="105,31,0,0" VerticalAlignment="Top" Width="75" Click="Button_Click"/>
  </Grid>
</Window>

And then I tried to make an event to print out some test texts when the button is pressed like this:

  public partial class MainWindow : Window {
    public MainWindow() {
      InitializeComponent();
    }

    private void Button_Click(object sender, RoutedEventArgs e) {
      TestRtb.Document.Blocks.Clear();
      for(int i = 0; i < 64; ++i) {
        TestRtb.AppendText("i: " + i.ToString() + "\n");
        printBits(i);
        printBits(toBitSquare(i));
        TestRtb.AppendText("\n");
      }
    }

    private void printBits(int i) {
      string text = i.ToBitArrayString();
      TestRtb.AppendText(text + "\n");
    }

    public static int toBitSquare(int square) {
      return ((square & ~7) >> 1) | (square & 7);
    }
  }

'ToBitArrayString()' is my own int extension. It is basically used to print its bit array representation. And this is what happen when I run my program and press the button:

enter image description here

Everything works as expected, except the first line "\n" is not printed. What happened?

Just in case you want to replicate, my extension functions are as follow:

private static string toBitArrayString(BitArray b, int spacePerByte = 1, int spacePerNibble = 0) {
  StringBuilder sb = new StringBuilder();
  for (int j = b.Length - 1; j >= 0; --j) {
    int i = b.Length - 1 - j;
    if (i % 4 == 0 && i > 0 && spacePerNibble > 0)
      sb.Append(string.Concat(Enumerable.Repeat(" ", spacePerNibble)));
    if (i % 8 == 0 && i > 0 && spacePerByte > 0)
      sb.Append(string.Concat(Enumerable.Repeat(" ", spacePerByte)));
    sb.Append(b[j] ? 1 : 0);
  }
  return sb.ToString();
}

public static string ToBitArrayString(this int input, int spacePerByte = 1, int spacePerNibble = 0) {
  BitArray b = new BitArray(new int[] { input });
  return toBitArrayString(b, spacePerByte, spacePerNibble);
}

Upvotes: 2

Views: 329

Answers (1)

Gupta
Gupta

Reputation: 324

The Rich Text Box that is shipped with .NET Framework 3.5 SP1 contains a bug. When converting plain text that contains a line break (\r), not to confuse with a new paragraph (\n). Use this working:- TestRtb.AppendText("i: " + i.ToString() + "\r");

Upvotes: 3

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