Net Core Connection String Dapper visual studio 2017

Question

I am trying to get a Connection String set up in my .Net Core application but i keep getting the error:

System.NullReferenceException: \'Object reference not set

Answer 1

If you are using appsettings.json, create a simple POCO class to model your connection string configurations like this:

public class ConnectionConfig
{
        public string Analysis {get;set;}
}

Add this line in ConfigureServices method in Startup.cs

services.Configure(Configuration.GetSection("ConnectionStrings"));

Data service class

class YourClass{
    private string _connectionString;

    YourClass(string connectionString){
       _connectionString = connectionString;
    }

    //Your implementation
    public List ReadAll()
    {
        var data = new List();
        using (IDbConnection db = new SqlConnection(_connectionString)
        {
            data = db.Query("select * from testTable").ToList();
        }

       return data;
   }
}

Inject IOptions in your controller constructor .

class YourController : Controller{
   YourClass _testing;

   YourController(IOptions connectionConfig){
       var connection = connectionConfig.Value;
       string connectionString = connection.Analysis;
       _testing = new YourClass(connectionString );
    }
   public IActionResult Index() { 
        var testingData = _testing.ReadAll(); 
        return View(); 
     }
 }