c# - Check if .NETCore is installed using CustomAction with Wix

Question

I want to cancel the installation if the NetCore 3.1 (preview) is not installed

I create this CustomAction :

using Microsoft.Deployment.WindowsInstaller;
using Microsoft.Win32;

namespace WixCustomAction
{
    public class CustomActions
    {
        [CustomAction]
        public static ActionResult CheckDotNetCore31Installed(Session session)
        {
            session.Log("Begin CheckDotNetCore31Installed");

            RegistryKey lKey = Registry.LocalMachine.OpenSubKey(@"SOFTWAREdotnetSetupInstalledVersionsx64sharedhost");

            var version = (string)lKey.GetValue("Version");

            session["DOTNETCORE31"] = version == "3.1.0-preview3.19553.2" ? "1" : "0";

            return ActionResult.Success;
        }
    }
}

Then in the WXS file :

<<?xml version="1.0" encoding="UTF-8"?>
<Wix xmlns="http://schemas.microsoft.com/wix/2006/wi"
     xmlns:netfx="http://schemas.microsoft.com/wix/NetFxExtension">

   <Product ...>

  (...)

    <Property Id="DOTNETCORE31">0</Property>

    <Condition Message="You must first install the .NET Core 3.1 Runtime">
      Installed OR DOTNETCORE31="1"
    </Condition>

    <InstallExecuteSequence>
      <Custom Action="Check.NetCore" Before="LaunchConditions">NOT Installed</Custom>
    </InstallExecuteSequence>

  </Product>

  <Fragment>
    <Binary Id="WixCA.dll" SourceFile="$(var.WixCustomAction.TargetDir)$(var.WixCustomAction.TargetName).CA.dll" />
    <CustomAction Id="Check.NetCore" BinaryKey="WixCA.dll" DllEntry="CheckDotNetCore31Installed" Execute="immediate"  />
  </Fragment>

And this is where I have a problem because I always get the warning message. An idea ? thanks

Answer 1

Debugging: Are you attaching the debugger to your custom action so you can see what is going on there? I bet it is not setting your property correctly. The custom action might not be running at all? Show a message box to smoke test that? More involved (attaching Visual Studio debugger):

• Direct video link (please watch it, very short and nice - from the Advanced Installer guys)

• Answer on debugging (skim if not using attached debugger please)

• See debugging section here (more comprehensive, more links)

LaunchCondition: In an MSI database launch conditions are represented by records in the LaunchCondition table. This table has two columns. The Condition column contains an expression which must evaluate to True for installation to continue:

Conclusion: So your condition does not evaluate to true properly. What is the actual value of DOTNETCORE31? I bet it is 0. Double check please. Easiest way is obviously to set it to 1 instead of 0 directly - and then compile again and test. Hard coding temporarily like this:

<Property Id="DOTNETCORE31">1</Property>

---

Links: Here are some previous answer on launch conditions and other topics:

• Previous Answer: Check if prerequisites are installed before installing a windows installer package
• C++ Custom Action: Interrupt installation when custom action returns error (C++ is great for minimal dependencies and debugability - it runs native, no layers, emulation and stuff that can break)
• How to execute conditional custom action on install and modify only? (basic WiX markup for VBScript custom actions)
• Windows Installer Deferred execution - how can we log the custom actions running in deferred mode?

---

WiX Custom Action: You have the basic markup for calling the custom action? Check the compiled MSI with Orca to see if there are entries in the Binary, CustomAction and InstallExecuteSequence and InstallUISequence tables. Some mock-up WiX markup (pillage gihub.com for samples?):

<Binary Id="CustomActions" SourceFile="C:Test.CA.dll" />

<...>

<CustomAction Id="CustomAction1" BinaryKey="CustomActions" DllEntry="CustomAction1"/>

<...>

<InstallUISequence>
  <Custom Action="CustomAction1" After="CostFinalize" />
</InstallUISequence>

<...>

<InstallExecuteSequence>
  <Custom Action="CustomAction1" After="CostFinalize" />
</InstallExecuteSequence>

GUI & Silent Install: Obviously you could also run the custom action from a dialog event - like a button click - but that would make it NOT run in silent mode. The GUI is skipped in silent mode so you need to run the custom action in the InstallExecuteSequence as well as the GUI.