wpf中RichTextBox文本内容的赋值与获取

赋值：

richtextbox.Document.Blocks.Clear();

string srt="12356457";

Run run=new Run(str);

Paragraph p=new Paragraph();

p.Inlines.add(run);

richtextbox.Document.Blocks.Add(p);

获取：

TextRange textRange = new TextRange(richtextbox.Document.ContentStart, richtextbox.Document.ContentEnd);

return textRange.Text;