How to Fix "The ConnectionString property has not been initialized." In ASP.NET Core 8,MVC in visual studio 22

Question

I am working on a project called:"MecoManageMovies" Using ASP.NET Core 8, C# MVC in Visual Studio 22 In Update_Datebase in PM, I get:"The ConnectionString property has not been initialized."

Answer 1

Hi @Merlyn Coleman,
The error message is caused by the connection string is not in appsettings.json/ appsettings.Development.json(it cannot find the connection string If your environment is not Development when you store it in appsettings.Development.json) . Be sure your connection string stores in appsettings.json. And the root key name must be ConnectionStrings, for example:

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },

  "ConnectionStrings": {
    "DefaultConnection": "Server=(localdb)\\mssqllocaldb;Database=YourDatabaseName;Trusted_Connection=True;MultipleActiveResultSets=true"
  }
}

Also be sure the key name is spelled correctly, you can set the breakpoint to check if the connectionString variable contains value:

var connectionString = builder.Configuration.GetConnectionString("DefaultConnection") ?? throw new InvalidOperationException("Connection string 'DefaultConnection' not found.");
builder.Services.AddDbContext<YourDbContext>(options =>
    options.UseSqlServer(connectionString));

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Best regards,
Rena