Added overload for "TryCreate" with validation error.

Author: PawelGerr

Directory.Build.props

@@ -2,7 +2,7 @@
 
    <PropertyGroup>
       <Copyright>(c) $([System.DateTime]::Now.Year), Pawel Gerr. All rights reserved.</Copyright>
-      <VersionPrefix>7.4.0</VersionPrefix>
+      <VersionPrefix>7.5.0</VersionPrefix>
       <Authors>Pawel Gerr</Authors>
       <GenerateDocumentationFile>true</GenerateDocumentationFile>
       <PackageProjectUrl>https://github.com/PawelGerr/Thinktecture.Runtime.Extensions</PackageProjectUrl>

samples/Thinktecture.Runtime.Extensions.Samples/ValueObjects/ValueObjectDemos.cs

@@ -51,6 +51,9 @@ private static void DemoForSimpleValueObjects(ILogger logger)
       if (ProductName.TryCreate("Milk", out milk))
          logger.Information("Product name '{Name}' created with 'TryCreate'.", milk);
 
+      if (!ProductName.TryCreate("X", out _, out var error))
+         logger.Information("Failed to create a product with name 'X'. Error: {Error}", error.Message);
+
       // Thanks to setting "NullInFactoryMethodsYieldsNull = true" the method "Create" returns null
       var nullProduct = ProductName.Create(null);
       logger.Information("Null-Product name: {NullProduct}", nullProduct);
@@ -181,6 +184,9 @@ private static void DemoForComplexValueObjects(ILogger logger)
       if (Boundary.TryCreate(lower: 1, upper: 2, out var boundaryWithTryCreate))
          logger.Information("Boundary with TryCreate: {Boundary}", boundaryWithTryCreate);
 
+      if (!Boundary.TryCreate(lower: 2, upper: 1, out _, out var error))
+         logger.Information("Failed to create Boundary (2, 1). Error: {Error}", error.Message);
+
       var validationError = Boundary.Validate(lower: 1, upper: 2, out var boundaryWithValidate);
 
       if (validationError is null)

src/Thinktecture.Runtime.Extensions.SourceGenerator/CodeAnalysis/ValueObjects/ComplexValueObjectCodeGenerator.cs

@@ -180,7 +180,28 @@ private void GenerateTryCreateMethod()
       _sb.Append(@"
          [global::System.Diagnostics.CodeAnalysis.NotNullWhen(true)] out ").Append(_state.TypeFullyQualifiedNullAnnotated).Append(@" obj)
       {
-         var validationError = Validate(");
+         return ").Append(_state.Settings.TryCreateFactoryMethodName).Append("(");
+
+      _sb.RenderArguments(fieldsAndProperties);
+
+      if (fieldsAndProperties.Count > 0)
+         _sb.Append(", ");
+
+      _sb.Append(@"out obj, out _);
+      }");
+
+      _sb.Append(@"
+
+      public static bool ").Append(_state.Settings.TryCreateFactoryMethodName).Append("(");
+
+      _sb.RenderArgumentsWithType(fieldsAndProperties, @"
+         ", ",", trailingComma: true);
+
+      _sb.Append(@"
+         [global::System.Diagnostics.CodeAnalysis.NotNullWhen(true)] out ").Append(_state.TypeFullyQualifiedNullAnnotated).Append(@" obj,
+         [global::System.Diagnostics.CodeAnalysis.NotNullWhen(false)] out ").Append(_state.ValidationError.TypeFullyQualified).Append(@"? validationError)
+      {
+         validationError = Validate(");
 
       _sb.RenderArguments(fieldsAndProperties);
 

src/Thinktecture.Runtime.Extensions.SourceGenerator/CodeAnalysis/ValueObjects/KeyedValueObjectCodeGenerator.cs

@@ -323,7 +323,17 @@ private void GenerateTryCreateMethod(bool allowNullOutput, bool emptyStringYield
 
       public static bool ").Append(_state.Settings.TryCreateFactoryMethodName).Append("(").RenderArgumentWithType(_state.KeyMember, useNullableTypes: allowNullOutput).Append(emptyStringYieldsNull ? "," : ", [global::System.Diagnostics.CodeAnalysis.NotNullWhen(true)]").Append(" out ").Append(_state.TypeFullyQualifiedNullAnnotated).Append(@" obj)
       {
-         var validationError = Validate(").RenderArgument(_state.KeyMember).Append(@", null, out obj);
+         return ").Append(_state.Settings.TryCreateFactoryMethodName).Append("(").RenderArgument(_state.KeyMember).Append(@", out obj, out _);
+      }");
+
+      _sb.Append(@"
+
+      public static bool ").Append(_state.Settings.TryCreateFactoryMethodName).Append(@"(
+         ").RenderArgumentWithType(_state.KeyMember, useNullableTypes: allowNullOutput).Append(@",
+         ").Append(emptyStringYieldsNull ? null : "[global::System.Diagnostics.CodeAnalysis.NotNullWhen(true)] ").Append("out ").Append(_state.TypeFullyQualifiedNullAnnotated).Append(@" obj,
+         [global::System.Diagnostics.CodeAnalysis.NotNullWhen(false)] out ").Append(_state.ValidationError.TypeFullyQualified).Append(@"? validationError)
+      {
+         validationError = Validate(").RenderArgument(_state.KeyMember).Append(@", null, out obj);
 
          return validationError is null;
       }");