windows installer - WIX: Setting a registry value from a dialog checkbox

Question

Using Wix for the first time in 10+ years, and first time with forms/dialog entry.

Have a property defined more or less like this:

<Property Id="THE_FLAG">
  <RegistrySearch Id="SearchTheFlag"  Root="HKLM" Key="SOFTWARE$(var.Manufacturer)$(var.SimpleProductName)" Name="the_flag"  Win64="$(var.Win64)" Type="raw" />
</Property>

Have a control in a form to set it:

<Control Id="TheFlagCheckBox" Type="CheckBox" X="45" Y="80" Width="220" Height="17" Property="THE_FLAG" CheckBoxValue="1" Text="Flag for something" />

At the end I want to write it:

<RegistryKey Root='HKLM' Key='SOFTWARE$(var.Manufacturer)$(var.SimpleProductName)' ForceCreateOnInstall='yes' >
    <RegistryValue Name='the_flag'     Type ='integer' Value='[THE_FLAG]' />
</RegistryKey>

If I select the checkbox, it sets the registry value. However, if I don't check the checkbox, then I get a warning when running the installer about not being able to acces the registry value. I think it is because the "value" of "THE_FLAG" is null or the empty string. I want to avoid the nasty warning to the user. I took over some code, and the previous owner used all strings for obviously DWORD values...maybe to get around the warning.

Can I set some conditionals or set the value of THE_FLAG to "0" if it is "" or null?

question from:https://stackoverflow.com/questions/65897025/wix-setting-a-registry-value-from-a-dialog-checkbox

Answer 1

Add the following to your authoring:

<SetProperty Id="THE_FLAG" Value="0" Before="InstallInitialize" Sequence="execute">NOT THE_FLAG</SetProperty>

This will set the value of THE_FLAG to "0" if it's blank (in MSI, null and empty string are both blank) before the registry writes are done. A reasonable alternate value for Before is "WriteRegistryValues".