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

Question

I am running WMI queries but I need a way to test that the connection is working properly before running any queries.

Below is the method that I created for to test the connection before running any query.

Any ideas on how I can test the connection for failure?

         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;
    }

Answer 1

If your program crashes inside the try catch statement, then it appears as if the return exception is not of type ManagementException or System.UnauthorizedAccessException

Try instead, simply using Catch(Exception ex) which should catch ALL exceptions, then trigger the error by mistyping information and see what error type it is, then handle that. Your error handling seems adequate with a message box and what I presume is kicking the routine back to the user to fix the input and resubmit, so I would mimic the same functionality with whatever error the system kicks out.