Why an empty RichtTextBox has "\r\n" as text?-CodePudding

This is a text editor. I am trying to open a new file and if the existing file is not empty, users get a warning to save the file or not. But if I use the condition if (text== ""), the value of text still has "\r\n" new line value. Even I didn't click on the text area. Why does string get the value of the new line? It doesn't have to be empty?

private void New_Click(object sender, RoutedEventArgs e)
{
    var text = new TextRange(richtxtbox.Document.ContentStart, richtxtbox.Document.ContentEnd).Text; 

    if (text == "")
    {
        MainWindow newWindow = new MainWindow();
        newWindow.Show();
        Window.GetWindow(this).Close();
    }
    else
    {
        // ...       
    }
}

I have to do this:

if (text == "" || text == "\r\n")
{
    MainWindow newWindow = new MainWindow();
    newWindow.Show();
    Window.GetWindow(this).Close();
}

CodePudding user response：

You wrote:

I am trying to open a new file and if the existing file is not empty...

What do you mean "the existing file is not empty"? I guess you mean the current content of the RichtextBox, that actually is container for the FlowDocument object. Right?

Result of the var text = new TextRange(richtxtbox.Document.ContentStart, richtxtbox.Document.ContentEnd).Text depend on content of the FlowDocument.

If you declare RichTextBox as below than text will contain "\r\n". It's because the FlowDocument will contain one Paragraph block. And when this paragraph is converted to text it will automatically appended with the Environment.NewLine.

<RichTextBox Name="richtxtbox">
    <FlowDocument>
        <Paragraph>          
        </Paragraph>
    </FlowDocument>
</RichTextBox>

But if you declare RichTextBox as empty FlowDocument than text will be empty - it contains 0 blocks.

<RichTextBox Name="richtxtbox">
    <FlowDocument>
    </FlowDocument>
</RichTextBox>

For more information read the following article: RichTextBox Overview