c# - 我如何放入异常捕获

Question

我有下面的代码，它通过并返回磁盘信息。运行时，我注意到某些 WMI 属性在我的计算机上不可用(即 FirmwareRevision)。

因此，当我运行代码时，VS 崩溃并显示“未找到”。知道我是如何在未找到对象的输出中设置异常捕获以声明“不可用”的。

我一直在阅读有关异常捕获的内容，但到目前为止我的业余方法是明确定义我想使用的异常...该程序打算在不同服务器的负载上运行，因此希望它能够智能地找出 WMI 对象任何一台服务器都可能没有。

代码如下，目前它失败了(最后一行):

"lblFirmware.Text = "Firmware: " +moDisk["FirmwareRevision"].ToString();"

代码:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Management;
using Microsoft.Win32;

namespace diskdrive_info
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            //Get all the disk drives
            ManagementObjectSearcher mosDisk = new ManagementObjectSearcher("SELECT * FROM Win32_DiskDrive");
            // Loop through each object (disk) retrieved by WMI
            foreach (ManagementObject moDisk in mosDisk.Get())
            {
                cmbHdd.Items.Add(moDisk["Model"].ToString());
            }
        }

        private void cmbHdd_SelectedIndexChanged(object sender,EventArgs e)
        {
            ManagementObjectSearcher mosDisks = new ManagementObjectSearcher("SELECT * FROM Win32_DiskDrive WHERE Model = '" + cmbHdd.SelectedItem + "'");
            foreach (ManagementObject moDisk in mosDisks.Get())
            {
                lblType.Text = "Type: " + moDisk["MediaType"].ToString();
                lblModel.Text = "Model: " + moDisk["Model"].ToString();
                lblCapacity.Text = "Capacity: " + moDisk["Size"].ToString();
                lblPartitions.Text = "Partitions: " + moDisk["Partitions"].ToString();
                lblSectors.Text = "Sectors: " + moDisk["SectorsPerTrack"].ToString();
                lblSignature.Text = "Signatures: " +moDisk["Signature"].ToString();
                lblFirmware.Text = "Firmware: " +moDisk["FirmwareRevision"].ToString();
            }
        }


    }
}

Answer 1

尝试替换:

lblFirmware.Text = "Firmware: " +moDisk["FirmwareRevision"].ToString();

与:

lblFirmware.Text = "Firmware: " + moDisk["FirmwareRevision"] == null ? "Not Available" :  moDisk["FirmwareRevision"].ToString();