title: DbContextOptionsBuilder could not be found ASP.NET Core 1.1 Web API project
body: <p>I'm trying to add Entity Framework Core 1.1 to my project and use a connection String to get my data from a Azure database. I tried reading the changes on <a href="https://blogs.msdn.microsoft.com/dotnet/2016/11/16/announcing-entity-framework-core-1-1/" rel="nofollow noreferrer">https://blogs.msdn.microsoft.com/dotnet/2016/11/16/announcing-entity-framework-core-1-1/</a> where they say, that i should do this in my Startup.cs file to connect to the DB:</p>
  
  <pre><code>protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
  {
      optionsBuilder
          .UseSqlServer(
              "connection string",
              options =&gt; options.EnableRetryOnFailure());
  }
  </code></pre>
  
  <p>But it just gives me an error:</p>
  
  <blockquote>
    <p>The type or namespace 'DbContextOptionsBuilder' could not be found...</p>
  </blockquote>
  
  <p>and </p>
  
  <blockquote>
    <p>'Startup.OnConfiguring(DbContextOptionsBuilder): No suitable method
    found to override.</p>
  </blockquote>
  
  <p>I can add <strong>using Microsoft.EntityFrameworkCore;</strong> which will make the error with DbContextOptionsBuilder disappear, but then the <strong>.UseSqlServer</strong> is getting an error: </p>
  
  <blockquote>
    <p>'DbContextOptionsBuilder' does not contain a definition for
    'UseSqlServer' and no extension method ...</p>
  </blockquote>
  
  <p>This is my dotnet.csproj file
  <a href="https://i.stack.imgur.com/gbRs9.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/gbRs9.png" alt="dotnet.csproj"></a></p>
  
  <p>How to fix this problem, so i can connect to my Db on Azure and get the data?</p>
  
  <p>Thanks in advance!</p>