将项目从2个列表框添加到一个列表框

Question

嗨，我如何将项目从2 listBox添加到一个listBox

例如：listBox1包含Hello listBox2包含World！ 因此，如果在列表框3中单击button1，将显示Hello World！ 并排，但不要换行

你好

世界！

    private void button2_Click(object sender, EventArgs e)
    {
      listBox3.Items.Add(listBox1.Items + listBox2.Items);
    }

还有1个如何从2个listBox.items中创建HttpWebRequest

    private void button1_Click(object sender, EventArgs e)
    {
        WebRequest request = WebRequest.Create(listBox1.Items + listBox2.Items);
    }

例如：listBox1包含http://test.com listBox2包含/index.html因此，如果单击button1，它将把listBox1和listBox2中的项目合并为1个项目，因此它将成为http://test.com/index.html并发送对网站的要求

还有1个为什么此代码停在catch（WebException x）

以及为什么返回false； 当button1_click无效时无法正常工作，我尝试将按钮设置为bool类型，但会导致listBox1错误。

    private void button1_Click(object sender, EventArgs e)
    {
        try
        {
            for (int i = 0; i < listBox1.Items.Count; i++)
            {
                // Create a request for the URL.        
                WebRequest request = WebRequest.Create(listBox1.Items[i].ToString());
                // If required by the server, set the credentials.
                request.Credentials = CredentialCache.DefaultCredentials;
                // Get the response.
                HttpWebResponse response = (HttpWebResponse)request.GetResponse();
                // Display the status.
                // Get the stream containing content returned by the server.
                Stream dataStream = response.GetResponseStream();
                // Open the stream using a StreamReader for easy access.
                StreamReader reader = new StreamReader(dataStream);
                // Read the content. 
                string responseFromServer = reader.ReadToEnd();
                // Display the content.
                if (response.StatusCode == HttpStatusCode.OK)
                {
                    listBox2.Items.Add(listBox1.Items[i]);
                }
                // Cleanup the streams and the response.
                reader.Close();
                dataStream.Close();
                response.Close();
            }

            }
        catch (WebException x)
        {
            listBox2.Items.Add("Error! " + x.Message);
        } 
    }

任何帮助将不胜感激谢谢。

Answer 1

对于第一部分：

listbox3.items.add(listbox1.SelectedItem.ToString() + listbox2.SelectedItem.ToString());

对于第二部分：

WebRequest request = WebRequest.Create(listBox1.SelectedItem.ToString() +   
listBox2.SelectedItem.ToString());

最后阶段：

If exception occurs and different url is expected then do select different url entries    
from both listbox1 and listbox2 and click the button to check. Also keep correct 
entries in both the listboxes to avoid exception.

Answer 2

1. 从列表框中获取选定的项：ListBox1.SectedItem
2. 连接字符串：string1 + string2
3. 将项目添加到ListBox：ListBox1.Items.Add（“ item_name_or_value”）