Failed to convert parameter C# / SQL Server

Question

Getting error:

Failed to convert parameter value from string to a Int32

I write that code for my form and at finally when run the co

Answer 1

why you don't use

comm.Parameters.AddWithValue("@cod", T4.Text);

comm.Parameters.AddWithValue("@facultate", C1.Text);
comm.Parameters.AddWithValue("@domeniul", T1.Text);
    ... 

comm.Parameters.AddWithValue("@d_inscriere", DTP1.Value);

    ...
    etc

Answer 2

You are setting int parameter with strings like in:

comm.Parameters.Add(new SqlParameter("@cod", SqlDbType.Int) { Value = T4.Text });

You should parse the value in all these lines that are integers with something like:

comm.Parameters.Add(new SqlParameter("@cod", SqlDbType.Int) { Value = int.Parse(T4.Text) });