从richTextBox失去字符串并且保存到文本中

从richTextBox得到字符串并且保存到文本中

主要代码如下：      //参考资料：http://dingxq.blog.163.com/blog/static/1305257612011037370779/  部分解析请点击链接

            saveFileDialog = new SaveFileDialog();

            saveFileDialog.RestoreDirectory = true;//保存对话框是否记忆上次打开的目录
            saveFileDialog.DefaultExt = "txt";
            saveFileDialog.AddExtension = true;
            saveFileDialog.FileName = "a";
            saveFileDialog.InitialDirectory = @fullPathname;
            saveFileDialog.OverwritePrompt = true;
            saveFileDialog.Title = "保存文件";
            saveFileDialog.ValidateNames = true;
            string saveStr = null;
            TextRange textRange = new TextRange(codeText.Document.ContentStart,codeText.Document.ContentEnd);
            saveStr = textRange.Text;
            if (saveFileDialog.ShowDialog().Value)
            {
                using (StreamWriter write = new StreamWriter(saveFileDialog.FileName))
                {
                    write.WriteLine(saveStr);
                }
            }