replace函数问题

Question

c.SelectedRtf(this.richTextBox1.SelectedRtf.Length   >   0) 
                        { 
                                this.richTextBox1.SelectedRtf.Replace(this.richTextBox1.SelectedText,   DateTime.Now.ToShortTimeString()   +   "   "   +   DateTime.Now.ToShortDateString()); 
                        } 
                        else 
                        { 
                                this.richTextBox1.AppendText(DateTime.Now.ToShortTimeString()   +   "   "   +   DateTime.Now.ToShortDateString()); 
                        }   

Answer 1

this.richTextBox1.Text = this.richTextBox1.Text.Replace(this.richTextBox1.SelectedText,   DateTime.Now.ToShortTimeString()   +   "   "   +   DateTime.Now.ToShortDateString());

Answer 2

-_-!!!测试看效果吧richTextBox1.SelectedText = DateTime.Now.ToShortTimeString() + " " + 
    DateTime.Now.ToShortDateString();

Answer 3

this.richTextBox1.Text   =   this.richTextBox1.Text.Replace(this.richTextBox1.SelectedText,       DateTime.Now.ToShortTimeString()       +       "       "       +       DateTime.Now.ToShortDateString());

Answer 4

问题已经解决，谢谢各位！            if (this.richTextBox1.SelectedText.Length > 0)
            {
                this.richTextBox1.SelectedText = DateTime.Now.ToShortTimeString() + " " + DateTime.Now.ToShortDateString();
            }
            else
            {
                this.richTextBox1.AppendText(DateTime.Now.ToShortTimeString() + " " + DateTime.Now.ToShortDateString());
            }
这段就可以了。