c# - 如果当前变量为空，如何跳到下一个项目

Question

我有一个函数可以检索设备名称列表，然后将其存储在一个变量中。然后下一步是每行使用 1 个设备名称获取信息并继续直到循环完成。

 String text = "";
        String errors = "";

    for (int i = 0; i < collection.Result.Count; i++)
    {
        deviceNames += collection.Result[i].DeviceName + Environment.NewLine;

        getvirtuals.Location = deviceNames;
        var virtuals = client.GetKnownVirtuals(getvirtuals, LtmKeyType.VirtualAddressPort);

        if (virtuals.Result == null)
        {
            i++;
            getvirtuals.Location = deviceNames;

        for (int v = 0; v < virtuals.Result.Count; v++)
                {
                try
                {
                    LtmKey virtualKey = new LtmKey();
                    virtualKey.Location = virtuals.Result[v].Location;
                    virtualKey.LocationType = virtuals.Result[v].LocationType;
                    virtualKey.Key = virtuals.Result[v].Key;
                    virtualKey.KeyType = LtmKeyType.VirtualAddressPort;

                    virtualKey.AdminGroup = admingroupComboBox.Text;


                    var memberStatus = client.GetMemberStatus(virtualKey);


                    for (int j = 0; j < memberStatus.Result.Count; j++)
                    {
                        VirtualMemberStatus status = memberStatus.Result[j];
                        text += String.Format("{5},{4},{0},{1},{2},{3}" + Environment.NewLine, status.Member.Address, status.Member.Port, status.EffectiveStatus, status.DesiredStatus, virtualKey.Key.Replace(":", ","), DateTime.UtcNow);
                        toolStripProgressBar1.PerformStep();
                    }
                }
                catch
                {
                    errors += String.Format("{0} Error Code: 2, Error occurred, check device name (case senstive) and admin group. This error may also occur due to connection loss, try again." + Environment.NewLine, DateTime.UtcNow);
                }
            }
            this.allResultsBox.Text = text;

        getallstatusButton.Enabled = true;
    }

    }

我遇到的问题是，如果 virtuals 为 null，工具会崩溃，而我想做的是如果 virtuals = null 我想继续列表中的下一项。我已经尝试了一个 if 语句，但它没有按计划工作，它仍然返回 null。

Answer 1

好吧，这似乎是一个问题:

if (virtuals.Result == null)
{
    i++;
    getvirtuals.Location = deviceNames;

    for (int v = 0; v < virtuals.Result.Count; v++)

    ...

如果 virtuals.Result 为 null，您希望 virtuals.Result.Count 如何工作？我怀疑你的意思是:

if (virtuals.Result != null)

但是，我怀疑你真的只是想要:

// Keep going with the next iteration of the for loop
if (virtuals == null || virtuals.Results == null)
{
    continue;
}