C# PDF4Net：段落最后一行的文本对齐

我正在使用O2 Solutions提供的名为PDF4NET的dll

我有如下代码：

PDFTextFormatOptions tfo new PDFTextFormatOptions;
tfo.Align = TextAlign.TopJustified;

tfo.KeepWhiteSpaces = True;
tfo.LineSpacing = 2;
string ltrtxt = "IMPORTANT: This is just some text representing a paragraph. This is just some extra text to make the paragraph longer.";
pdfPage.Canvas.DrawHTMLTextBox(ltrtxt, 
    PDFReportsConfig.Arial_HTML11, 
    Nothing, 
    PDFReportsConfig.BlackBrush, 
    y, x, 3, 2, tfo);

IMPORTANT: This is just some  text 
representing a paragraph.  This is 
just some  extra text  to make the 
paragraph                  longer.

ltrtxt += vbCrLf
ltrtxt += vbCr
ltrtxt += vbLf

这将创建一个如下所示的段落：

PDFTextFormatOptions tfo new PDFTextFormatOptions;
tfo.Align = TextAlign.TopJustified;

tfo.KeepWhiteSpaces = True;
tfo.LineSpacing = 2;
string ltrtxt = "IMPORTANT: This is just some text representing a paragraph. This is just some extra text to make the paragraph longer.";
pdfPage.Canvas.DrawHTMLTextBox(ltrtxt, 
    PDFReportsConfig.Arial_HTML11, 
    Nothing, 
    PDFReportsConfig.BlackBrush, 
    y, x, 3, 2, tfo);

IMPORTANT: This is just some  text 
representing a paragraph.  This is 
just some  extra text  to make the 
paragraph                  longer.

ltrtxt += vbCrLf
ltrtxt += vbCr
ltrtxt += vbLf

也就是说，该段是左右对齐的

IMPORTANT: This is just some  text 
representing a paragraph.  This is 
just some  extra text  to make the 
paragraph longer.

我希望保持对齐，但我也希望最后一行不对齐

IMPORTANT: This is just some  text 
representing a paragraph.  This is 
just some  extra text  to make the 
paragraph longer.

如何使段落完全对齐，但允许最后一行左对齐

当我在谷歌上搜索“PDFTextFormatOptions”（带引号）时，我得到两个结果

我继承了这个项目，所以我不知道原始文档在哪里

[编辑] 我试图在字符串的末尾添加换行符，但没有效果。我是这样加的：

PDFTextFormatOptions tfo new PDFTextFormatOptions;
tfo.Align = TextAlign.TopJustified;

tfo.KeepWhiteSpaces = True;
tfo.LineSpacing = 2;
string ltrtxt = "IMPORTANT: This is just some text representing a paragraph. This is just some extra text to make the paragraph longer.";
pdfPage.Canvas.DrawHTMLTextBox(ltrtxt, 
    PDFReportsConfig.Arial_HTML11, 
    Nothing, 
    PDFReportsConfig.BlackBrush, 
    y, x, 3, 2, tfo);

IMPORTANT: This is just some  text 
representing a paragraph.  This is 
just some  extra text  to make the 
paragraph                  longer.

ltrtxt += vbCrLf
ltrtxt += vbCr
ltrtxt += vbLf

也就是说：我分别尝试了这三个元素。

如果在文本末尾添加

“
”

html元素，最后一行将不再对齐

IMPORTANT: This is just some  text 
representing a paragraph.  This is 
just some  extra text  to make the 
paragraph longer.

请注意，较旧版本的PDF4NET可能需要

“
”

，而不是

“
”