Adds support for Using EntityTypeConfiguration files.

[jwyza-pi]

Handles most of #2583. (won't be handling the GUI side of things)

TODO:

• - Add Code to Ensure the scaffolded configuration files are put into the Configurations folder.
• - Pass the rootNameSpace into the scaffolding.
• - Customize the DbContext.t4 to support EntityTypeConfiguration.t4
• - Add a new config option: use-t4-split to CLI
• - Warn if using both use-t4 and use-t4-split. In the case of using both, respect use-t4 instead.
• - Only use the rootNameSpace value if use-t4-split is used.
• - Add new zip files for .net 8 that are similar to T4_800.zip, named T4_800_Split.zip that contains the EntityTypeConfiguration.t4 and the modified DbContext.t4 (and the EntityType.t4)
  • - Add the functionality to unzip this file into CodeTemplates in the event that they don't exist.

Couple items on this approach:

1. I grabbed the EntityTypeConfiguration from https://github.com/R4ND3LL/EntityFrameworkRuler/blob/main/src/EntityFrameworkRuler.Design/Resources/EntityTypeConfiguration.t4 (which was linked in T4 customizations and tips #1499. It's for .Net7, but for whatever reason, MS didn't include it in their ef templates for .net 8 :(.

2. You need to have context-splitting-preview turned off.

3. One note is that to make this work you need to have a modified version of DbContext.t4 that replaces the ModelLines with calling the ApplyConfiguration instead. Not sure how we want to represent this if someone wants to use this. This is now covered by having the version of the DbContext.t4 in the T4_800_Split.zip file.

So before: (leaving the info below just for future reference as to what is different)

     StringBuilder mainEnvironment;
    foreach (var entityType in Model.GetEntityTypes().Where(e => !e.IsSimpleManyToManyJoinEntityType()))
    {
        // Save all previously generated code, and start generating into a new temporary environment
        mainEnvironment = GenerationEnvironment;
        GenerationEnvironment = new StringBuilder();

        if (anyConfiguration)
        {
            WriteLine("");
        }

        var anyEntityTypeConfiguration = false;
#>

After:

    foreach (var entityType in Model.GetEntityTypes().Where(e => !e.IsSimpleManyToManyJoinEntityType()))
    {
        // Save all previously generated code, and start generating into a new temporary environment
        mainEnvironment = GenerationEnvironment;
        GenerationEnvironment = new StringBuilder();

        if (anyConfiguration)
        {
            WriteLine("");
        }
        
        #>
        modelBuilder.ApplyConfiguration(new Configurations.<#= entityType.Name #>Configuration());
<#
        anyConfiguration = true;
        mainEnvironment.Append(GenerationEnvironment);
        // Resume generating code into the main environment
        GenerationEnvironment = mainEnvironment;
        continue;

        var anyEntityTypeConfiguration = false;
#>

[jwyza-pi]

@ErikEJ The only thing I don't have is the unzipping of the file. I looked and it seems like the code that drops the templates is only called via the GUI. Unless I'm missing something.

[ErikEJ]

There is a T4Helper class (I also missed that when updating to EF Core 9)

[jwyza-pi]

Ok, I think it's ready now. I did not add .Net 9 versions of the split entities largely because I don't have any of the net9 stuff setup atm.

[ErikEJ]

This is great, just added a few comments

[ErikEJ]

Thanks, this is a great addition

[ErikEJ]

I plan to release a new non-nightly version sometime next week after .NET 9 RTW