Question

我试图搞清楚以下问题，但我无法做到这一点，因为我刚开始编程一个月前。

我有一个包含20个项目的列表框：

private void loadDownloadXMLListBox()
{
    var items = new[] { "BARC", "DEV", "DOM", "EZJ", "GFS", 
                        "IHG", "JD.", "LAD", "LLOY", "MRW", 
                        "NXT", "OCDO", "RBS", "SMWH", "SPD", 
                        "STAN", "SYR", "TALK", "TSCO", "WMH" };
    foreach (var item in items) listDownloadXML.Items.Add(item);

    listDownloadXML.SelectedIndex = -1;
}

这是我从网站下载单个选定文件的代码：

private void btnDownloadXML_Click(object sender, EventArgs e)
{
    using (WebClient client = new WebClient())
    {
        client.DownloadFile("http://www.lse.co.uk/chat/" + listDownloadXML.SelectedItem,
                                                    @"..\..\sharePriceXML\" +
                                         listDownloadXML.SelectedItem + ".xml");
    }
    MessageBox.Show("Download Completed! File has been placed in the folder sharePriceXML!");
}

我想点击“全部下载”按钮，然后下载网站上的所有20个项目。我可以知道如何循环列表框中的20个项目并将它们全部下载到文件夹而不选择项目吗？谢谢。

Answer 1

foreach (var item in listDownloadXML.Items)
{
    //... your code to download "item".
}

Answer 2

您可以首先将单个文件功能的下载外部化为单独的可重用方法：

public void DownloadFile(string item)
{
    using (var client = new WebClient())
    {
        client.DownloadFile(
             "http://www.lse.co.uk/chat/" + item,
             @"..\..\sharePriceXML\" + item + ".xml"
        );
    }
    MessageBox.Show("Download Completed! File has been placed in the folder sharePriceXML!");
}

然后：

private void btnDownloadXML_Click(object sender, EventArgs e)
{
    DownloadFile((string)listDownloadXML.SelectedItem);
}

现在关于多个文件的问题=＆gt;你使用循环并为列表框中的每个元素调用DownloadFile方法：

foreach (string item in listDownloadXML.Items)
{
    DownloadFile(item);
}

从列表框中的项目下载多个文件

2 个答案: