Update src/Definition/Share/Services/CommandService.cs

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: niltor

src/Definition/Share/Services/CommandService.cs

@@ -104,6 +104,11 @@ out string error
         OutputHelper.Success($"Created new solution {solutionPath}");
 
         var id = await solutionService.SaveSolutionAsync(solutionPath, dto.Name);
+        if (id == null)
+        {
+            ErrorMsg = "Failed to save solution, id is null.";
+            return false;
+        }
         await projectContext.SetProjectByIdAsync(id);
 
         OutputHelper.Important($"Apply settings...");