diff --git a/scripts/dotnet/offline.cs b/scripts/dotnet/offline.cs
index 110d521e..95030d26 100644
--- a/scripts/dotnet/offline.cs
+++ b/scripts/dotnet/offline.cs
@@ -59,6 +59,7 @@ namespace SherpaOnnx
     public string Provider;
   }
 
+  [StructLayout(LayoutKind.Sequential)]
   public struct OfflineTtsConfig
   {
     public OfflineTtsConfig()