.Net support notes

Since version 3.1, Tarma ExpertInstall supports the installation of .Net assemblies with the following features:

• A requirements check for the .Net runtime.
• Two variables (MsiNetAssemblySupport and VersionCLR) to check the .Net runtime version elsewhere in the project.
• Detection of .Net assemblies when you add new files to the project.
• An Assembly-type of component;
• Installation of both private and global assemblies (the latter into the GAC).

All this functionality is built into the installer; no external tools such as GACUTIL.exe are required.

Adding .Net assemblies to your project

The easiest way to add .Net assemblies to your Tarma ExpertInstall project is to add them as installation files. Tarma ExpertInstall will detect .Net assemblies and create separate assembly-type components for them with the required settings.

To add .Net assemblies manually, do the following:

1. On the Components and Features project page, create a new Assembly object.
2. Add the installation file that contains the .Net manifest to the newly created assembly (right-click on the assembly object in the Components and Assemblies tree, then choose Add Object...).
3. If necessary, add any further non-manifest files and other installation resources to the assembly in the same manner. Note that all files in the assembly must be installed in the same folder.
4. Set the assembly's Folder alias field to the installation folder of the manifest file.
5. Click the ... (browse) button to the right of the Manifest file field and select the manifest file for the assembly.

Global assemblies

By default, assemblies are assumed to be private to your application; if you want register them as global assemblies, you must do the following:

1. Ensure that all your assembly manifest files are signed and contain a public key or public key token. This is required to generate a strong name for the assembly.
2. Install the assemblies in the GlobalAssemblyCache folder in your Tarma ExpertInstall project. You can find this folder as Target System\Windows Volume\Windows\assembly.
3. Check the Global assembly box of each Assembly component and ensure that the Folder alias field is set to GlobalAssemblyCache.

Tarma ExpertInstall will produce a number of diagnostic warnings if you build a project that does not conform to these requirements. DO NOT IGNORE these warnings.

COM interop registration

There is no built-in support yet for COM interop registration. The recommended approach to register your .Net assemblies for backward compatibility with COM is as follows:

1. Add the .Net assembly files to the ExpertInstall project. This will detect the assemblies and create corresponding Assembly-Components for them.
2. Separately, run regasm yourassembly.dll /regfile on each of the assemblies that require COM interoperability. You might want to add /codebase, but only if your assemblies are signed and contain a public key (or token).
3. Back in ExpertInstall, import the REGEDIT4 files produced by the previous step into your project. When asked, add them to the component that corresponds to the assembly to which they belong.

You can find the regasm.exe tool in the .Net installation folder on your system, typically C:\WINDOWS\Microsoft.NET\Framework\v1.1.4322 or something similar.

Detection of .Net

The simplest method of checking for .Net runtime support is to specify it as a System Requirement in your ExpertInstall project. However, this simply prevents installation if the correct .Net version is not present on the system, without opportunity to install it.

An alternative method is therefore to NOT list .Net as a system requirement, but to use conditional actions to warn the user of a missing .Net runtime and/or to install it.

There are two variables that you can use in the conditions.

MsiNetAssemblySupport

MsiNetAssemblySupport contains the dotted-decimal CLR version number, for example 1.1.4322.2032. You can use this one in conditional expressions like:

 <$vercmp(<MsiNetAssemblySupport>, 1.1)> >= 0

This only works for Tarma native installers; MSI doesn't support the $vercmp syntax. (Ironically, although the MsiNetAssemblySupport property originates with MSI, MSI has no means to use its value other than as an null/not-null test.)

VersionCLR

VersionCLR contains the CLR version number encoded as 1000 * major + 10 * minor:

• .Net 1.0 = 1000
• .Net 1.1 = 1010
• .Net 2.0 = 2000

This one can be used more easily in both Tarma and MSI projects:

 VersionCLR >= 1010

VersionCLR is not a standard MSI property, but Tarma's MSI runtime support DLL will set it in each MSI installer built with Tarma ExpertInstall.

Installation of .Net runtime

See How to install the .Net runtime