[CLI] Add framework selection to interactive flow for aspire new

src/Aspire.Cli/DotNet/DotNetCliRunner.cs

@@ -30,7 +30,7 @@ internal interface IDotNetCliRunner
     Task<int> CheckHttpCertificateAsync(DotNetCliRunnerInvocationOptions options, CancellationToken cancellationToken);
     Task<int> TrustHttpCertificateAsync(DotNetCliRunnerInvocationOptions options, CancellationToken cancellationToken);
     Task<(int ExitCode, string? TemplateVersion)> InstallTemplateAsync(string packageName, string version, FileInfo? nugetConfigFile, string? nugetSource, bool force, DotNetCliRunnerInvocationOptions options, CancellationToken cancellationToken);
-    Task<int> NewProjectAsync(string templateName, string name, string outputPath, string[] extraArgs, DotNetCliRunnerInvocationOptions options, CancellationToken cancellationToken);
+    Task<int> NewProjectAsync(string templateName, string name, string outputPath, string? framework, string[] extraArgs, DotNetCliRunnerInvocationOptions options, CancellationToken cancellationToken);
     Task<int> BuildAsync(FileInfo projectFilePath, DotNetCliRunnerInvocationOptions options, CancellationToken cancellationToken);
     Task<int> AddPackageAsync(FileInfo projectFilePath, string packageName, string packageVersion, string? nugetSource, DotNetCliRunnerInvocationOptions options, CancellationToken cancellationToken);
     Task<(int ExitCode, NuGetPackage[]? Packages)> SearchPackagesAsync(DirectoryInfo workingDirectory, string query, bool prerelease, int take, int skip, FileInfo? nugetConfigFile, DotNetCliRunnerInvocationOptions options, CancellationToken cancellationToken);
@@ -410,11 +410,28 @@ private static bool TryParsePackageVersionFromStdout(string stdout, [NotNullWhen
         }
     }
 
-    public async Task<int> NewProjectAsync(string templateName, string name, string outputPath, string[] extraArgs, DotNetCliRunnerInvocationOptions options, CancellationToken cancellationToken)
+    public async Task<int> NewProjectAsync(string templateName, string name, string outputPath, string? framework, string[] extraArgs, DotNetCliRunnerInvocationOptions options, CancellationToken cancellationToken)
     {
         using var activity = telemetry.ActivitySource.StartActivity();
 
-        string[] cliArgs = ["new", templateName, "--name", name, "--output", outputPath, ..extraArgs];
+        var cliArgsList = new List<string>
+        {
+            "new",
+            templateName,
+            "--name",
+            name,
+            "--output",
+            outputPath
+        };
+
+        if (!string.IsNullOrEmpty(framework))
+        {
+            cliArgsList.Add("--framework");
+            cliArgsList.Add(framework);
+        }
+
+        string[] cliArgs = [.. cliArgsList, ..extraArgs];
+
         return await ExecuteAsync(
             args: cliArgs,
             env: null,

src/Aspire.Cli/Resources/TemplatingStrings.resx

@@ -226,4 +226,10 @@
   <data name="NuGetConfigCreatedConfirmationMessage" xml:space="preserve">
     <value>Created NuGet.config for the selected package channel.</value>
   </data>
+  <data name="PromptForFramework_Prompt" xml:space="preserve">
+    <value>Select a target framework</value>
+  </data>
+  <data name="PromptForFramework_UsingFramework" xml:space="preserve">
+    <value>Using {0} as target framework.</value>
+  </data>
 </root>

src/Aspire.Cli/Templating/DotNetTemplateFactory.cs

@@ -193,6 +193,24 @@ private async Task PromptForXUnitVersionOptionsAsync(ParseResult result, List<st
         extraArgs.Add(xunitVersion);
     }
 
+    private async Task<string?> PromptForFrameworkOptionsAsync(CancellationToken cancellationToken)
+    {
+        // Note: We don't check for --framework CLI option here because we're NOT adding that option
+        // This method is only for interactive prompting
+        var framework = await interactionService.PromptForSelectionAsync(
+            TemplatingStrings.PromptForFramework_Prompt,
+            ["net8.0", "net9.0", "net10.0"],
+            choice => choice,
+            cancellationToken);
+
+        if (!string.IsNullOrEmpty(framework))
+        {
+            interactionService.DisplayMessage("check_mark", string.Format(CultureInfo.CurrentCulture, TemplatingStrings.PromptForFramework_UsingFramework, framework));
+        }
+
+        return framework;
+    }
+
     private static void ApplyExtraAspireStarterOptions(Command command)
     {
         var useRedisCacheOption = new Option<bool?>("--use-redis-cache");
@@ -220,6 +238,11 @@ private async Task<TemplateResult> ApplyTemplateAsync(CallbackTemplate template,
         {
             var name = await GetProjectNameAsync(parseResult, cancellationToken);
             var outputPath = await GetOutputPathAsync(parseResult, template.PathDeriver, name, cancellationToken);
+
+            // Only prompt for framework selection in interactive mode (when no specific template was specified)
+            // This happens when the user runs just "aspire new" without a template name
+            var isInteractiveMode = parseResult.CommandResult.Command.Name == "new";
+            var framework = isInteractiveMode ? await PromptForFrameworkOptionsAsync(cancellationToken) : null;
 
             var source = parseResult.GetValue<string?>("--source");
             var selectedTemplateDetails = await GetProjectTemplatesVersionAsync(parseResult, cancellationToken: cancellationToken);
@@ -281,6 +304,7 @@ private async Task<TemplateResult> ApplyTemplateAsync(CallbackTemplate template,
                                 template.Name,
                                 name,
                                 outputPath,
+                                framework,
                                 extraArgs,
                                 options,
                                 cancellationToken);