实体框架核心 DbContext 设置 DbConnection

Question

In .NET Framework was DbContext in EntityFramework 6 was constructor where I can set DbConnection.

In EF .NET Core can I set DbContext DbConnection? I hit an exception in UseTransaction of DbContext method:

An exception of type 'System.InvalidOperationException' occurred in Microsoft.EntityFrameworkCore.Relational.dll but was not handled in user code: 'The specified transaction is not associated with the current connection. Only transactions associated with the current connection may be used.'

Does any body know how set the DbConnection? Or I have get a wrong way?

Answer 1

I have always added the Database Context within the startup file of .Net core apps by adding it to the IServiceCollection and pulling the string from the appsetting file like so:

        private void AddDatabase(IServiceCollection services)
    {
        var databaseConnectionString = Configuration.GetConnectionString("DatabseConnection");

        Check.CanConnectToDatabase(databaseConnectionString);

        services.AddDbContext<DatabaseContext>(
            options =>
            {
                options.ConfigureWarnings(
                    warnings => warnings.Throw(RelationalEventId.QueryClientEvaluationWarning));
                options.UseSqlServer(databaseConnectionString,
                    sqlOptions => sqlOptions.MigrationsHistoryTable(HistoryRepository.DefaultTableName, "SchemaName"));
            });
    }

Answer 2

If I understand correctly, you can not create DbConnection because it's a protected class hence you should get DbConnection then you set the connection string and finally set your DbCollection.

var dbConnection =  (await GetDbContextAsync()).Database.GetDbConnection();
dbConnection.ConnectionString = "yourConnectinString";
(await GetDbContextAsync()).Database.SetDbConnection(dbConnection);
//Also you can test your connection
await (await GetDbContextAsync()).Database.CanConnectAsync();

Maybe it's a tricky way but it worked for me. Regards