Fix nullable

GerbilManagerWebAPI/Controllers/LittersController.cs

@@ -49,8 +49,8 @@ namespace GerbilManagerWebAPI.Controllers
             Litter litter = new Litter{
                 Id = Guid.NewGuid(),
                 Date = dto.Date,
-                Father = gerbilrepository.GetGerbil(dto.Father),
-                Mother = gerbilrepository.GetGerbil(dto.Mother),
+                Father = gerbilrepository.GetGerbil(dto.Father ?? Guid.Empty),
+                Mother = gerbilrepository.GetGerbil(dto.Mother ?? Guid.Empty),
                 Name = dto.Name,
                 Strength = dto.Strength
             };
@@ -70,10 +70,10 @@ namespace GerbilManagerWebAPI.Controllers
             }
 
             Litter updatedLitter = existingItem with{
-                Date = litterDto.Date,
+                Date = litterDto.Date ?? DateTime.Now,
                 Strength = litterDto.Strength,
-                Father = gerbilrepository.GetGerbil(litterDto.Father),
-                Mother = gerbilrepository.GetGerbil(litterDto.Mother),
+                Father = gerbilrepository.GetGerbil(litterDto.Father ?? Guid.Empty),
+                Mother = gerbilrepository.GetGerbil(litterDto.Mother ?? Guid.Empty),
                 Name = litterDto.Name
             };
 

GerbilManagerWebAPI/Converter/LitterConverter.cs

@@ -10,8 +10,8 @@ namespace GerbilManagerWebAPI.Converter
             return new LitterDto{
                 Id = litter.Id,
                 Date = litter.Date,
-                Father = litter.Father.AsDto(),
-                Mother = litter.Mother.AsDto(),
+                Father = litter.Father?.AsDto(),
+                Mother = litter.Mother?.AsDto(),
                 Name = litter.Name,
                 Strength = litter.Strength
             };

GerbilManagerWebAPI/Dtos/CreateLitterDto.cs

@@ -5,7 +5,7 @@ namespace GerbilManagerWebAPI.Dtos
         public required string Name { get; init; }
         public required DateTime Date { get; init; }
         public int? Strength { get; init; }
-        public Guid Father { get; init; }
-        public Guid Mother { get; init; }
+        public Guid? Father { get; init; }
+        public Guid? Mother { get; init; }
     }
 }

GerbilManagerWebAPI/Dtos/UpdateBreederDto.cs

@@ -3,6 +3,6 @@ namespace GerbilManagerWebAPI.Dtos
 {
     public record UpdateBreederDto
     {
-        public string Name { get; init; }
+        public string? Name { get; init; }
     }
 }

GerbilManagerWebAPI/Dtos/UpdateGerbilDto.cs

@@ -2,9 +2,9 @@ namespace GerbilManagerWebAPI.Dtos
 {
     public record UpdateGerbilDto
     {
-        public string Name { get; init; }
-        public GenderDto Gender { get; init; }
-        public LitterDto Litter { get; init; }
-        public BreederDto Breeder { get; init; }
+        public string? Name { get; init; }
+        public GenderDto? Gender { get; init; }
+        public LitterDto? Litter { get; init; }
+        public BreederDto? Breeder { get; init; }
     }
 }

GerbilManagerWebAPI/Dtos/UpdateLitterDto.cs

@@ -3,10 +3,10 @@ namespace GerbilManagerWebAPI.Dtos
 {
     public record UpdateLitterDto
     {
-        public string Name { get; init; }
-        public DateTime Date { get; init; }
-        public int Strength { get; init; }
-        public Guid Father { get; init; }
-        public Guid Mother { get; init; }
+        public string? Name { get; init; }
+        public DateTime? Date { get; init; }
+        public int? Strength { get; init; }
+        public Guid? Father { get; init; }
+        public Guid? Mother { get; init; }
     }
 }

GerbilManagerWebAPI/Models/Breeder.cs

@@ -6,6 +6,6 @@ namespace GerbilManagerWebAPI.Models
     {
         [Key]
         public Guid Id { get; init; }
-        public required string Name { get; init; }
+        public required string Name { get; set; }
     }
 }

GerbilManagerWebAPI/Models/Gerbil.cs

@@ -5,10 +5,10 @@ namespace GerbilManagerWebAPI.Models
     public record Gerbil
     {
         [Key]
-        public Guid Id { get; init; }
-        public required string Name { get; init; }
-        public Gender Gender { get; init; }
-        public Litter? Litter { get; set; }
-        public Breeder? Breeder { get; set; }
+        public Guid Id { get; init; } // init => properties are immutable by default, they are only mutable in the constructor and initializer.
+        public required string Name { get; set; } //required => parameter is necessary in constructor and object iniilization list. So it cannot be intantiated without it
+        public required Gender Gender { get; set; }
+        public Litter? Litter { get; set; } // Any variable where the ? isn't appended to the type name is a non-nullable reference type.
+        public Breeder? Breeder { get; set; } // You use the null-forgiving operator ! following a variable name to force the null-state to be not-null. For example, if you know the name variable isn't null but the compiler issues a warning, you can write the following code to override the compiler's analysis:
     }
 }

GerbilManagerWebAPI/Models/Litter.cs

@@ -6,11 +6,11 @@ namespace GerbilManagerWebAPI.Models
     {
         [Key]
         public Guid Id { get; init; }
-        public required string Name { get; init; }
-        public required DateTime Date { get; init; }
-        public int? Strength { get; init; }
-        public Gerbil? Father { get; init; }
-        public Gerbil? Mother { get; init; }
+        public required string Name { get; set; }
+        public required DateTime Date { get; set; }
+        public int? Strength { get; set; }
+        public Gerbil? Father { get; set; }
+        public Gerbil? Mother { get; set; }
     }
 }