Hello,
Thanks for your post.
Please change the type (.NET Framework 4 Client Profile) of .NET Framework in your project to .NET Framework 4, and then reference the corresponding dlls (Spire.Barcode.dll, Spire.License.dll ) from
Spire.BarCode for .NET Version:3.1 NET folder to get rid of these errors and warnings. If there is any other question, just feel free to write back.
Sincerely,
Lisa
E-iceblue support team