c# - Cannot convert expression type 'lambda expression' to return type 'System.Linq.Expressions.Expression<System.Func<IProduct,string,bool>>' -

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ok, i'm lost. why 1st function wrong (squiglies in lambda expression), 2nd 1 right (meaning compiles)?

    public static expression<func<iproduct, string, bool>> isvalidexpression(string val)     {         return (h => h.product_name == val);      }      public static expression<func<iproduct, bool>> isvalidexpression2()     {         return (m => m.product_name == "ace");      }

your first function going need 2 arguments. func<x,y,z> defines 2 parameters , return value. since have both iproduct , string parameters, you'll need 2 arguments in lambda.

  public static expression<func<iproduct, string, bool>> isvalidexpression(string val)   {         return ((h, i) => h.product_name == val);   }

your second function func<x,y>, means function signature has 1 parameter, , lambda statement compiles.


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