错误 CS0246：找不到类型或命名空间名称“MySql”

Question

im trying to connect to my mysql database for my project but im getting the following error:

error CS0246: The type or namespace name 'MySql' could not be found

full error:

[Running] mono "C:\\Users\\Aidan\\AppData\\Roaming\\Code\\User\\cs-script.user\\cscs.exe" "d:!computer science!!NEA!\\test stuff\\sql\\c# sql test 1.cs" Error: Specified file could not be compiled.

csscript.CompilerException: d:!computer science!!NEA!\\test stuff\\sql\\c# sql test 1.cs(3,7): error CS0246: The type or namespace name 'MySql' could not be found (are you missing a using directive or an assembly reference?) d:!computer science!!NEA!\\test stuff\\sql\\c# sql test 1.cs(4,7): error CS0246: The type or namespace name 'MySql' could not be found (are you missing a using directive or an assembly reference?) d:!computer science!!NEA!\\test stuff\\sql\\c# sql test 1.cs(5,7): error CS0246: The type or namespace name 'MySql' could not be found (are you missing a using directive or an assembly reference?)

at csscript.CSExecutor.ProcessCompilingResult (System.CodeDom.Compiler.CompilerResults results, System.CodeDom.Compiler.CompilerParameters compilerParams, CSScriptLibrary.ScriptParser parser, System.String scriptFileName, System.String assemblyFileName, System.String[] additionalDependencies) [0x00102] in :0 at csscript.CSExecutor.Compile (System.String scriptFileName) [0x0080d] in :0 at csscript.CSExecutor.ExecuteImpl () [0x005a1] in :0

[Done] exited with code=1 in 5.388 seconds

im using visual studio code, (visual studio is broken, says free trial has expired for community)

when looking at other problems like this online i wasnt able to find anything that fixed it, some sites were going on about dlls and stuff but i wasnt able to understand what they were trying to do, so please explain exactly what it is i need to do.

im using c#, running the server off the same computer and i am able to connect to it and edit the databases using popsql.

here is the code i am using:

using System;
using System.Data;

using MySql.Data;
using MySql.Data.MySqlClient;

public class Tutorial2
{
    public static void Main()
    {
        string connStr = "server=localhost;user=****;database=*****;port=****;password=***********";
        MySqlConnection conn = new MySqlConnection(connStr);
        try
        {
            Console.WriteLine("Connecting to MySQL...");
            conn.Open();

            string sql = "SELECT Name, HeadOfState FROM Country WHERE Continent='Oceania'";
            MySqlCommand cmd = new MySqlCommand(sql, conn);
            MySqlDataReader rdr = cmd.ExecuteReader();

            while (rdr.Read())
            {
                Console.WriteLine(rdr[0]+" -- "+rdr[1]);
            }
            rdr.Close();
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.ToString());
        }

        conn.Close();
        Console.WriteLine("Done.");
    }
}

(i replaced password etc with stars)

Answer 1

If you are getting errors on your using tags, it is most likely not your code that is wrong but the files your are tying to reference. Some of the MySQL dll's may be corrupt or missing.

Answer 2

You can try the following:

1. Check project references. If MySql exists in references but has aa warning (a yello triangle), then need to delete and add the .dll again. Easier way is to install a nuget package.

2. Alternatively, check the Project's framework. If the .Net version of project is less than the MySql's one, then need to change the Project's target framework.