c# 类型为“System.Runtime.InteropServices.COMException”的未处理异常

我正在运行WMI查询，但我需要一种方法在运行任何查询之前测试连接是否正常工作。

下面是我创建的用于在运行任何查询之前测试连接的方法。

关于如何测试连接是否失败的任何想法？

         private void btnQuery_Click(object sender, EventArgs e)
    {
        string strPC = txtPCName.Text.ToString();
        string strDrive = txtDrive.Text.ToString();
        if (strPC == "" || strDrive == "" || txtUser.Text.ToString() == "" || txtPW.Text.ToString() == "")
        {
            MessageBox.Show("The PC Name/ Drive Letter / Username / Or Password is blank. Please make sure all of these fields are filled out");
        }
        else
        {
            //Set up the connection first and test that it is working properly
            ConnectionOptions connection = new ConnectionOptions();
            connection.Username = txtUser.Text;
            connection.Password = txtPW.Text;
            connection.Authority = "ntlmdomain:expd";
            ManagementScope mgmtScope = new ManagementScope("''''" + strPC + "''root''cimv2", connection);
            if (pTestWMIConnection(mgmtScope) == true)
            {
                //Get PC Information
                double dblMem = pGetMemUsage("FreePhysicalMemory", mgmtScope);
                double dblTotDisk = pGetTotalDiskSpace(strDrive, mgmtScope);
                double dblFreeDisk = pGetFreeDiskSpace(strDrive, mgmtScope);
                txtMem.Text = Math.Round(dblMem, 2).ToString() + " MB";
                txtDriveTot.Text = Math.Round(dblTotDisk, 2).ToString() + " GB";
                txtFreeDisk.Text = Math.Round(dblFreeDisk, 2).ToString() + " GB";
                txtSN.Text = pGetWMIInfo("Win32_BIOS", "SerialNumber", mgmtScope);
                txtIP.Text = pGetIPAddress("Win32_NetworkAdapterConfiguration", "IPAddress", mgmtScope);
                txtModel.Text = pGetWMIInfo("Win32_ComputerSystem", "Model", mgmtScope);
                txtArch.Text = pGetWMIInfo("Win32_OperatingSystem", "OSArchitecture", mgmtScope);
                SetBalloonTip("Complete", "PC Query Completed");
            }
            else
            {
                MessageBox.Show("Connection to remote PC failed"); 
            }
        }           
    } 

 public static bool pTestWMIConnection(ManagementScope mgmtScope)
    {
        try
        {
            mgmtScope.Connect();
            if (mgmtScope.IsConnected == true)
            {
                return true;
            }
        }
        catch (ManagementException err)
        {
            MessageBox.Show("Unable to Return some or all of the information requested - " + err.Message);
            return false;
        }
        catch (System.UnauthorizedAccessException unauthorizedErr)
        {
            MessageBox.Show("Username or Password might be incorrect - " + unauthorizedErr.Message);
            return false;
        }
        return false;
    }