New overload: implementing IModelCacheKeyFactory

entity-framework/core/modeling/dynamic-model.md

@@ -21,6 +21,10 @@ The following implementation takes the `UseIntProperty` into account when produc
 
 [!code-csharp[Main](../../../samples/core/Modeling/DynamicModel/DynamicModelCacheKeyFactory.cs?name=DynamicModel)]
 
+If you have to support [Design-time DbContext creation](xref:core/cli/dbcontext-creation)(Needed by, for example, the Migration commands), you have to use the new overload for the Create method. As in the following example:
+
+[!code-csharp[Main](../../../samples/core/Modeling/DynamicModel/DynamicModelCacheKeyFactoryDesignTimeSupport.cs?name=DynamicModelDesignTimeSupport)]
+
 Finally, register your new `IModelCacheKeyFactory` in your context's `OnConfiguring`:
 
 [!code-csharp[Main](../../../samples/core/Modeling/DynamicModel/DynamicContext.cs?name=OnConfiguring)]

samples/core/Modeling/DynamicModel/DynamicModelCacheKeyFactoryDesignTimeSupport.cs

@@ -0,0 +1,18 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+
+namespace EFModeling.DynamicModel
+{
+    #region DynamicModelDesignTimeSupport
+    public class DynamicModelCacheKeyFactory : IModelCacheKeyFactory
+    {
+        public object Create(DbContext context, bool designTime)
+            => context is DynamicContext dynamicContext
+                ? (context.GetType(), dynamicContext.UseIntProperty, designTime)
+                : (object)context.GetType();
+
+        public object Create(DbContext context)
+            => Create(context, false);
+    }
+    #endregion
+}