WiX: Setting values as a Composite of Multiple Properties - windows

Question

Is it possible, and if so how can I create a single value from multiple properties within a WiX installation project?
Specifically, I have some dialog like this...
<Dialog Id="ConnectionStringDlg" Width="370"
Height="270" Title="Database Settings - [ProductName]" NoMinimize="yes">
<!-- Connection String -->
<Control Id="TitleLabel" Type="Text" X="45" Y="60" Width="100" Height="15" TabSkip="yes" Text="Connection String" />
<Control Id="DSLabel" Type="Text" X="45" Y="77"
Width="100" Height="15" TabSkip="no" Text="&Data Source: " />
<Control Id="DSEdit" Type="Edit" X="45" Y="92"
Width="220" Height="18" Property="CONNECTION_STRING_DS" Text="{200}" />
<Control Id="ICLabel" Type="Text" X="45" Y="107"
Width="100" Height="15" TabSkip="no" Text="&Initial Catalog: " />
<Control Id="ICEdit" Type="Edit" X="45" Y="122"
Width="220" Height="18" Property="CONNECTION_STRING_IC" Text="{200}" />
<Control Id="UIDLabel" Type="Text" X="45" Y="137"
Width="100" Height="15" TabSkip="no" Text="&User ID: " />
<Control Id="UIDEdit" Type="Edit" X="45" Y="152"
Width="220" Height="18" Property="CONNECTION_STRING_UI" Text="{200}" />
<Control Id="PassLabel" Type="Text" X="45" Y="167"
Width="100" Height="15" TabSkip="no" Text="&Password: " />
<Control Id="PassEdit" Type="Edit" X="45" Y="182" Password="yes"
Width="220" Height="18" Property="CONNECTION_STRING_PASS" Text="{200}" />
<!-- Back button -->
<!--<Control Id="Back" Type="PushButton" X="180" Y="243"
Width="56" Height="17" Text="&Back">
<Publish Event="NewDialog" Value="PoolSettingsDlg">1</Publish>
</Control>-->
<Control Id="Next" Type="PushButton" X="236" Y="243"
Width="56" Height="17" Default="yes" Text="&Next">
<Publish Event="NewDialog" Value="CustomizeDlg">
<!--if settings are correct, allow next dialog-->
<![CDATA[CONNECTION_STRING <> ""]]>
</Publish>
</Control>
<Control Id="Cancel" Type="PushButton" X="304" Y="243"
Width="56" Height="17" Cancel="yes" Text="Cancel">
<Publish Event="SpawnDialog" Value="CancelDlg">1</Publish>
</Control>
<Control Id="BannerBitmap" Type="Bitmap" X="0" Y="0"
Width="370" Height="44" TabSkip="no" Text="WixUI_Bmp_Banner" />
<Control Id="Description" Type="Text" X="25" Y="23"
Width="280" Height="15" Transparent="yes" NoPrefix="yes">
<Text>Please enter database configuration</Text>
</Control>
<Control Id="BottomLine" Type="Line" X="0" Y="234" Width="370" Height="0" />
<Control Id="Title" Type="Text" X="15" Y="6"
Width="200" Height="15" Transparent="yes" NoPrefix="yes">
<Text>{\WixUI_Font_Title}Database Settings</Text>
</Control>
<Control Id="BannerLine" Type="Line" X="0" Y="44" Width="370" Height="0" />
</Dialog>
Which I am using to get connection string information from the end user in a user friendly way. I then set this value in a web.config file at install time using...
<Component Id="cmp623DDF82F0F7645ADAAF0E7573713162" Guid="{8CFDC325-BC71-4A2F-AB22-68B0AE56C98B}">
<File Id="fil5B0B918C0DAF7B2ECC5EB9C7CC0B9FFC" KeyPath="yes" Source="Publish\Web.config" />
<util:XmlFile Id="ModifyConnectionString"
Action="setValue"
Permanent="yes"
ElementPath="//configuration/connectionStrings/add[\[]#name='RawConnection'[\]]"
Name="connectionString"
File="[#fil5B0B918C0DAF7B2ECC5EB9C7CC0B9FFC]"
Value="[CONNECTION_STRING]"
SelectionLanguage="XSLPattern"
Sequence="1"/>
</Component>
My question is, how can I set the connection string value by making a composite from multiple properties set in the dialog?

Answer 1

You could use the MSI Community extensions for this as it provides you with a nice interface and will format the string for you.
However if you want to build it up manually you can just do the string building in the Value attribute:
<util:XmlFile Id="ModifyConnectionString"
Action="setValue"
Permanent="yes"
ElementPath="//configuration/connectionStrings/add[\[]#name='RawConnection'[\]]"
Name="connectionString"
File="[#fil5B0B918C0DAF7B2ECC5EB9C7CC0B9FFC]"
Value='Server=[CONNECTION_STRING_DS];Database=[CONNECTION_STRING_IC];User Id=[CONNECTION_STRING_UI];Password=[CONNECTION_STRING_PASS];'
SelectionLanguage="XSLPattern"
Sequence="1"/>
Alternatively if you need to set a single property to use in multiple places you can either use the CustomAction or the SetProperty elements (they both do the same thing):
<CustomAction Id='SetConnectionString'
Property='CONNECTION_STRING'
Before='ExecXmlFile'
Value='Server=[CONNECTION_STRING_DS];Database=[CONNECTION_STRING_IC];User Id=[CONNECTION_STRING_UI];Password=[CONNECTION_STRING_PASS];' />
<SetProperty Id='CONNECTION_STRING'
Before='ExecXmlFile'
Value='Server=[CONNECTION_STRING_DS];Database=[CONNECTION_STRING_IC];User Id=[CONNECTION_STRING_UI];Password=[CONNECTION_STRING_PASS];' />