Fix 500 when saving workflows.

src/Squidex/Areas/Api/Controllers/Apps/Models/UpdateWorkflowDto.cs

@@ -43,12 +43,7 @@ namespace Squidex.Areas.Api.Controllers.Apps.Models
                 Initial,
                 Steps?.ToDictionary(
                     x => x.Key,
-                    x => new WorkflowStep(
-                        x.Value?.Transitions.ToDictionary(
-                            y => y.Key,
-                            y => new WorkflowTransition(y.Value.Expression, y.Value.Role)),
-                        x.Value.Color,
-                        x.Value.NoUpdate)),
+                    x => x.Value?.ToStep()),
                 SchemaIds,
                 Name);
 

src/Squidex/Areas/Api/Controllers/Apps/Models/WorkflowDto.cs

@@ -46,16 +46,13 @@ namespace Squidex.Areas.Api.Controllers.Apps.Models
 
         public static WorkflowDto FromWorkflow(Guid id, Workflow workflow, ApiController controller, string app)
         {
-            var result = SimpleMapper.Map(workflow, new WorkflowDto { Id = id });
-
-            result.Steps = workflow.Steps.ToDictionary(
-                x => x.Key,
-                x => SimpleMapper.Map(x.Value, new WorkflowStepDto
+            var result = SimpleMapper.Map(workflow, new WorkflowDto
             {
-                    Transitions = x.Value.Transitions.ToDictionary(
-                        y => y.Key,
-                        y => new WorkflowTransitionDto { Expression = y.Value.Expression, Role = y.Value.Role })
-                }));
+                Steps = workflow.Steps.ToDictionary(
+                    x => x.Key,
+                    x => WorkflowStepDto.FromWorkflowStep(x.Value)),
+                Id = id
+            });
 
             return result.CreateLinks(controller, app, id);
         }

src/Squidex/Areas/Api/Controllers/Apps/Models/WorkflowStepDto.cs

@@ -7,7 +7,9 @@
 
 using System.Collections.Generic;
 using System.ComponentModel.DataAnnotations;
+using System.Linq;
 using Squidex.Domain.Apps.Core.Contents;
+using Squidex.Infrastructure.Reflection;
 
 namespace Squidex.Areas.Api.Controllers.Apps.Models
 {
@@ -28,5 +30,29 @@ namespace Squidex.Areas.Api.Controllers.Apps.Models
         /// Indicates if updates should not be allowed.
         /// </summary>
         public bool NoUpdate { get; set; }
+
+        public static WorkflowStepDto FromWorkflowStep(WorkflowStep step)
+        {
+            if (step == null)
+            {
+                return null;
+            }
+
+            return SimpleMapper.Map(step, new WorkflowStepDto
+            {
+                Transitions = step.Transitions.ToDictionary(
+                    y => y.Key,
+                    y => WorkflowTransitionDto.FromWorkflowTransition(y.Value))
+            });
+        }
+
+        public WorkflowStep ToStep()
+        {
+            return new WorkflowStep(
+                Transitions?.ToDictionary(
+                    y => y.Key,
+                    y => y.Value?.ToTransition()),
+                Color, NoUpdate);
+        }
     }
 }

src/Squidex/Areas/Api/Controllers/Apps/Models/WorkflowTransitionDto.cs

@@ -5,6 +5,8 @@
 //  All rights reserved. Licensed under the MIT license.
 // ==========================================================================
 
+using Squidex.Domain.Apps.Core.Contents;
+
 namespace Squidex.Areas.Api.Controllers.Apps.Models
 {
     public sealed class WorkflowTransitionDto
@@ -18,5 +20,20 @@ namespace Squidex.Areas.Api.Controllers.Apps.Models
         /// The optional restricted role.
         /// </summary>
         public string Role { get; set; }
+
+        public static WorkflowTransitionDto FromWorkflowTransition(WorkflowTransition transition)
+        {
+            if (transition == null)
+            {
+                return null;
+            }
+
+            return new WorkflowTransitionDto { Expression = transition.Expression, Role = transition.Role };
+        }
+
+        public WorkflowTransition ToTransition()
+        {
+            return new WorkflowTransition(Expression, Role);
+        }
     }
 }