Question

我是C＃的新手，想尝试一些问题。我创建了一个ListView来存储两个随机数的运算，所有这些运算都在一定的时间内发生。

这是我构造Listview的方式：
第一列称为“开始时间”，以记录计时器开始的时间。第二列的功能相同，只是“结束时间”。现在，它运行时，static int k = 10; ListViewItem lvi1 = new ListViewItem(); private void Bstart_Click(object sender, EventArgs e) { timer1.Start(); lvi1 = new ListViewItem(DateTime.Now.ToString("HH:mm:ss")); listView2.Items.Add(lvi1); } private void Timer1_Tick(object sender, EventArgs e) { Random ran1 = new Random(); Random ran2 = new Random(); double nu1 = ran1.Next(0, 100); double nu2 = ran2.Next(2, 270); string op; var operation = ran1.Next(1, 5); double res; if (k > 1) { label1.Text = k.ToString() + " seconds remaining"; } else if (k == 1) { label1.Text = k.ToString() + " seconds remaining"; } else { timer1.Stop(); lvi1.SubItems[1].Text = DateTime.Now.ToString("HH:mm:ss"); label1.Text = "You have 10 seconds"; //MessageBox.Show("You are out of time!", "Too Bad", MessageBoxButtons.OKCancel, MessageBoxIcon.Exclamation); k = 10; } k--; switch (operation) { case 1: res = nu1 + nu2; op = "+"; break; case 2: res = nu1 - nu2; op = "-"; break; case 3: res = nu1 * nu2; op = "*"; break; case 4: res = nu1 / nu2; op = "/"; break; default: res = 0; op = "?"; break; } textBox1.Text = Convert.ToString(nu1 + " " + op + " " + nu2 + " = " + res); listView2.Columns.Add("OP", 45, HorizontalAlignment.Center); lvi1.SubItems.Add(res.ToString()); } private void Bstop_Click(object sender, EventArgs e) { timer1.Stop(); }将以编程方式创建多个列以存储操作结果。
但是，程序运行时，结果将跳到保留第二列以记录“结束时间”。
我如何确保第二列为空，直到计时器结束，并且结果将从第三列开始到结尾？

代码如下：

public intercept(context: ExecutionContext, next: CallHandler): Observable<any> {

    if (!this.reflector.get<boolean>(RequestMetaData.IS_PUBLIC_ROUTE, context.getHandler())) {
        return next.handle().pipe(
          map(data => {
              const host = context.switchToHttp();
              const req = host.getRequest();
              const resp = host.getResponse();
              this.persistRequest(data, req, resp)
                .then(() => this.logger.log(`Request logged`))
                .catch(e => {
                    this.logger.error(`Error logging request: ${e.message}`);
                });
              return data;
          }));
    }
    return next.handle();
}

Answer 1

您可以添加一个占位符项，以用string.Empty或-填充第二列，直到您真正要填充它为止：

private void Bstart_Click(object sender, EventArgs e)
{
    timer1.Start();
    lvi1 = new ListViewItem(DateTime.Now.ToString("HH:mm:ss"));
    listView2.Items.Add(lvi1);

    // Add an empty SubItem or any placeholder here:
    // lvi1.SubItems.Add(string.Empty);
    lvi1.SubItems.Add("-");
}

就像我在评论中已经提到的那样，您的if(k > 1)和else if (k == 1)的内容完全相同。您可以合并这些：

if (k >= 1)
{
    label1.Text = k.ToString() + " seconds remaining";
}
else
{
    timer1.Stop();
    // ...

如何将子项目放在Listview中特定列旁边的列中？

1 个答案: