Handle optional properties in model From method

Updated the From method in the model template to check for the existence of optional properties in the input map before assigning values. This prevents errors when optional properties are missing from the input dictionary. (for examle in model: User, :-/ )

Author: Fellmonkey

templates/dotnet/Package/Models/Model.cs.twig

@@ -39,6 +39,7 @@ namespace {{ spec.title | caseUcfirst }}.Models
         public static {{ definition.name | caseUcfirst | overrideIdentifier }} From(Dictionary<string, object> map) => new {{ definition.name | caseUcfirst | overrideIdentifier }}(
             {%~ for property in definition.properties %}
             {{ property.name | caseCamel | escapeKeyword | removeDollarSign }}:{{' '}}
+                {%- if not property.required -%}map.ContainsKey("{{ property.name }}") ? {% endif %}
                 {%- if property.sub_schema %}
                     {%- if property.type == 'array' -%}
                         ((IEnumerable<object>)map["{{ property.name }}"]).Select(it => {{ property.sub_schema | caseUcfirst | overrideIdentifier }}.From(map: (Dictionary<string, object>)it)).ToList()
@@ -60,6 +61,7 @@ namespace {{ spec.title | caseUcfirst }}.Models
                         {%~ endif %}
                     {%~ endif %}
                 {%~ endif %}
+                {%- if not property.required %} : null{% endif %}
                 {%- if not loop.last or (loop.last and definition.additionalProperties) %},
                 {%~ endif %}
             {%~ endfor %}
@@ -96,4 +98,4 @@ namespace {{ spec.title | caseUcfirst }}.Models
         {%~ endif %}
         {%~ endfor %}
     }
-}
+}