Enabling excel add-in programmatically

Question

Sometimes my excel Addin gets disabled if it ends up being in the disabled COM Addins I can enable it with the following code. However if it ends up in disabled items I can't enable it using this code. Is there a way I can enable a disabled item. Not sure if I could do it using regedit or not.

I get a COM exception {"Operation aborted (Exception from HRESULT: 0x80004004 (E_ABORT))"}

    xl.Application myApp = new xl.Application();

    foreach (COMAddIn currentAddIn in myApp.COMAddIns)
    {
        if (currentAddIn.Description == "Create Excel AddIn" && !currentAddIn.Connect)
        {
            try
            {


                currentAddIn.Connect = true;
            }
            catch (Exception)
            {
                CommonMethods.ExceptionHandler("Create tab couldn't be enabled", new StackTrace(true).GetFrame(0).GetFileLineNumber(), new StackTrace(true).GetFrame(0).GetMethod());
            }


            break;
        }

    }


    return false;
}

You can't stop other people disabling you. "What would the world be like if this were possible?" https://blogs.msdn.microsoft.com/oldnewthing/20040216-00/?p=40603 — mjwills, Jun 29 '17 at 08:22
@mjwills can I not set something in the regedit to enable it again? — Craig Gallagher, Jun 29 '17 at 08:24
I'm running unit tests and sometimes the addin gets disabled. I have over 200 tests and can't just stop them so I can manually enable the addin — Craig Gallagher, Jun 29 '17 at 08:30
Run ProcessMonitor really quickly while you manually enable the Add-In to see which registry key/s switch it on or off — Jeremy Thompson, Jun 29 '17 at 09:14
@JeremyThompson in my regedit the path is Computer\HKEY_CURRENT_USER\Software\Microsoft\Office\Excel\Addins\Create.ExcelAddIn\LoadBehavior if I change the decimal to 3 it should enable the addin I think — Craig Gallagher, Jun 29 '17 at 09:28
@JeremyThompson this doesn't show me how to enable it programmatically though — Craig Gallagher, Jun 29 '17 at 09:49
Oh ok, have this registry class I designed here to do it programmatically: https://stackoverflow.com/q/26613336/495455 sorry that doesn't show how to set load behavior, you can Google that mate "c# set registry key" — Jeremy Thompson, Jun 29 '17 at 09:52

score 2 · Accepted Answer · edited Apr 30 '20 at 09:24

2

This was the best and most efficient solution.

using (RegistryKey myKey = Registry.CurrentUser.OpenSubKey(@"Software\Microsoft\Office\Excel\Addins\Create.ExcelAddIn", true))
{
    if (myKey != null)
    {
        myKey.SetValue("LoadBehavior", "3", RegistryValueKind.DWord);
        myKey.Close();
    }
}

edited Apr 30 '20 at 09:24

JohnLBevan

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answered Jun 29 '17 at 10:40

Craig Gallagher

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Hi, glad you got it working and it is good but it isn't the best, because RegistryKey is an unmanaged resource you have to Dispose it, that's why in the link I showed you I use `using`, eg `using (subkey = key.OpenSubKey(kn)) {` – Jeremy Thompson Jun 30 '17 at 02:34

score -1 · Answer 2 · answered Jun 29 '17 at 11:12

The only way that I know of for completely disabled add-ins is to delete the registry key in the location below, but it can't be done while Excel is open (change 16.0 to the Office version):

HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Word\Resiliency\DisabledItems\

Enabling excel add-in programmatically

2 Answers2