WiX: How to schedule the InstallUISequence

I am working on a installer. It is very simple; I just to write some key into the Windows Registry. But before doing this, I have to check some conditions, so I make four dialogs:

1. Welcome;

2. Check that connection to the Internet is available

3. Check that the database is accessible

4. Write the registry and show finish information.

And I schedule the InstallUISequence like below.

<InstallUISequence>
    <Show Dialog="Welcome"
          After="ExecuteAction"/>
</InstallUISequence>

And I use the "next" and "pre" to navigate the other dialogs. It works, but the welcome dialog do not show immediately. Half a minute after the prepare dialog and during this half a minute, it has no progress dialog - it seems the install has finished.

In view of this, I change the schedule like this in the Welcome dialog:

<InstallUISequence>
    <Show Dialog="Welcome"
          before="ExecuteAction"/>
 </InstallUISequence>

And in the writeRegistry dialog:

<InstallUISequence>
    <Show Dialog="writeRegistry"
          After="ExecuteAction"/>
</InstallUISequence>

I want to do the Execute开发者_StackOverflow中文版Action (write the registry) before showing the dialog writeRegistry. But it seems that there is nothing has been written into the registry.

What is the problem here and how can it be fixed?

ExecuteAction handles InstallExecuteSequence. So when this action starts, the installation is performed.

All your dialogs should be scheduled before ExecuteAction.