C# 是否有任何方法可以在不使用EF的情况下将MSSQL服务器连接到.NET CORE（2.2）API？

我是.NETCore的新手，到目前为止，我正在尝试从.NETCoreAPI连接MSSQL服务器中的现有数据库

但我找到的所有例子都是使用EF

但是我想从用户定义的类连接MSSQL服务器，如下所示

DataBaseConnection.cs

 public class DatabaseConnection 
    {
        private SqlDataAdapter sqlAdapter;
        private SqlConnection sqlConnection;
        SqlCommand sqlCommand = new SqlCommand();

        // Initialise Connection

        public DatabaseConnection()
        {
            sqlAdapter = new SqlDataAdapter();
            sqlConnection = new SqlConnection(ConfigurationManager.ConnectionStrings["DefaultConnection"].ConnectionString);
        }

        // Open Database Connection if Closed or Broken

        private SqlConnection openConnection()
        {
            if (sqlConnection.State == ConnectionState.Closed || sqlConnection.State == ConnectionState.Broken)
            {
                sqlConnection.Open();
            }
            return sqlConnection;
        }
}

在构造函数中，我得到的错误是

appsettings.json

{
  "ConnectionStrings": {
    "DefaultConnection": "Server=(localdb)\\mssqllocaldb;Database=HealthAPI;Trusted_Connection=True;MultipleActiveResultSets=true"
  },
  "Logging": {
    "LogLevel": {
      "Default": "Warning"
    }
  },
  "AllowedHosts": "*"
}

---

有没有可能在不使用EF的情况下连接数据库？

我是使用变通方法连接的。下面是代码

public abstract class BaseDataService
{
    private Database database = null;

    public BaseDataService()
    {
        DatabaseFactory.SetDatabaseProviderFactory(new DatabaseProviderFactory(new SystemConfigurationSource(false).GetSection), false);
        this.database = DatabaseFactory.CreateDatabase("_connection");
    }
    public Database SqlDatabase
    {
        get
        {
            return this.database;
        }

        set
        {
            this.database = value;
        }
    }
}

App.config文件

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <configSections>
    <section name="system.data" type="System.Data.Common.DbProviderFactoriesConfigurationHandler, Microsoft.Practices.EnterpriseLibrary.Data, Version=6.0.0.0, Culture=neutral, PublicKeyToken=null"/>
  </configSections>

  <connectionStrings>
    <add name="_connection" connectionString="Server=localhost;Database=DBNAME;Trusted_Connection=True;" providerName="System.Data.SqlClient"  />
  </connectionStrings>
</configuration>

像这样使用它

Configuration.GetSection("ConnectionStrings").DefaultConnection

---

对您遇到的错误与Configuration Manager有关。这不是数据库连接错误。如果你硬编码你的连接字符串在那里，它可能会工作。

<PackageReference Include="EnterpriseLibrary.Data.NetCore" Version="6.0.1313" />

public DatabaseConnection(IConfiguration configuration)
{
      string connectionString = configuration.GetConnectionString("DefaultConnection");
      sqlAdapter = new SqlDataAdapter();
      sqlConnection = new SqlConnection(connectionString);
}

Configuration.GetSection("ConnectionStrings").DefaultConnection