這里的默認配置文件指的是項目中的appsettings.json文件，我們可以把一些配置信息保存在里面，比如數據庫連接信息。

來吧，看例子：

1、先在appsettings.json文件中寫入數據庫的連接信息：

{

"Logging": {

"LogLevel": {

"Default": "Information",

"Microsoft": "Warning",

"Microsoft.Hosting.Lifetime": "Information"

}

},

"AllowedHosts": "*",

"DataBase": { //添加的數據庫連接

"Server": "m.xmbygy.com",

"Name": "fdsafdsa",

"UID": "321dwwq",

"PassWord": "sdfewwssva"

}

}

2、在Startup.cs的ConfigureServices中注入上下文類

services.AddTransient();

3、在上下文類EFCoreContext.cs中讀取配置信息

public class EFCoreContext : DbContext

{

private IConfiguration Configuration;

//通過構造函數注入Configuration對象

public EFCoreContext(IConfiguration configuration)

{

Configuration = configuration;

}

protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)

{

string server = Configuration["DataBase:Server"];

string name = Configuration["DataBase:Name"];

string uID = Configuration["DataBase:UID"];

string passWord = Configuration["DataBase:PassWord"];

string strConn = $"server = {server}; user id = {uID}; password ={passWord}; database = {name}";

optionsBuilder.UseSqlServer(strConn);//數據庫連接

}

}

4、獲取成功，如下圖：

這就是最簡單的一種方法，也是最實用的。