error in neural network for c#(.net Assemly)

Hello,

I always got same error all the time. I already no ideal what is the misdake i made.

C# error information：

... MWMCR::EvaluateFunction error ...

The 'STRING' input must be either a char row vector, a cell array of char row vectors, or a string array.

Error in => Mynntest.m at line 7.

Would anyone provide a direction for me ?

---------------------------------

My script ：

I compile my script for C#(.net Assemly). (storage path：C:\\ANN )

My C#：

Error information in C#：