C#：插入 mysql 表

Question

I am trying to connect to mysql from c# and insert into an existing table in a db.
The C#-Connector is installed and I added the following references:

C:/program files (x86)/mysql/connector net 8.0/assemblies/v4.5.2/mysql.data.dll
C:/program files (x86)/mysql/connector net 8.0/assemblies/v4.5.2/mysql.web.dll

I tried changing the @s to ?s which made no difference.

using MySql.Data.MySqlClient;

namespace ConnectToMysql
{
    class Program
    {
        static void Main(string[] args)
        {
            string txtTitle = "SharpConnector";
            string txtAuthor = "Myself";
            int myRating = 5;

            string myConnectionString = "Server=localhost;Database=mydb;Uid=root;Pwd=mypw";

            MySqlConnection mconnection = new MySqlConnection(myConnectionString);
            MySqlCommand cmd;
            //the next line causes an unhandled exception
            mconnection.Open();

            cmd = mconnection.CreateCommand();
            cmd.CommandText = "insert into books(title, author, myrating)values(@title,@author,@myrating)";
            cmd.Parameters.AddWithValue("@title", txtTitle);
            cmd.Parameters.AddWithValue("@author", txtAuthor);
            cmd.Parameters.AddWithValue("@myrating", myRating);
            cmd.ExecuteNonQuery();

            mconnection.Close();
        }
    }
}

Error: Unhandled exception. Cannot print exception string because >Exception.ToString() failed.

Answer 1

The C#-Connector is installed and I added the following references:

C:/program files (x86)/mysql/connector net 8.0/assemblies/v4.5.2/mysql.data.dll C:/program files (x86)/mysql/connector net 8.0/assemblies/v4.5.2/mysql.web.dll

This is not the appropriate way to add references to a C# project; it won't necessarily add all the dependencies (which is probably why you're getting the exception).

Remove those references, then (assuming you're using Visual Studio) right-click your project in Solution Explorer and choose Manage NuGet Packages. In the "Browse" tab, enter MySql.Data (or MySqlConnector for a more modern alternative), select it, then click "Install".