Исполнитель: вроде доделал всё

VeterinaryView/VeterinaryDatabaseImplement/Models/Pet.cs

@@ -52,7 +52,7 @@ namespace VeterinaryDatabaseImplement.Models
 				return _purchasePets;
 			}
 		}
-		public static Pet? Create(VeterinaryDatabase context, PetBindingModel model)
+		public static Pet? Create(PetBindingModel model)
 		{
 			if (model == null)
 			{
@@ -64,15 +64,7 @@ namespace VeterinaryDatabaseImplement.Models
 				PetName = model.PetName,
 				PetType = model.PetType,
 				PetBreed = model.PetBreed,
-				PetGender = model.PetGender,
-				Visits = model.VisitPets.Select(x => new VisitPet
-				{
-					Visit = context.Visits.First(y => y.Id == x.Key)
-				}).ToList(),
-				Purchases = model.PurchasePets.Select(x => new PurchasePet
-				{
-					Purchase = context.Purchases.First(y => y.Id == x.Key)
-				}).ToList()
+				PetGender = model.PetGender
 			};
 		}
 		public void Update(PetBindingModel model)

VeterinaryView/VeterinaryShowOwnerApp/VeterinaryShowOwnerApp.csproj

@@ -7,15 +7,11 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <Content Remove="Views\Home\CreatePet.cshtml" />
     <Content Remove="Views\Home\CreateVisit.cshtml" />
-    <Content Remove="Views\Home\DeletePet.cshtml" />
     <Content Remove="Views\Home\UpdatePet.cshtml" />
   </ItemGroup>
 
   <ItemGroup>
-    <Compile Include="Views\Home\CreatePet.cshtml" />
-    <Compile Include="Views\Home\DeletePet.cshtml" />
     <Compile Include="Views\Home\UpdatePet.cshtml" />
   </ItemGroup>
 

VeterinaryView/VeterinaryShowOwnerApp/Views/Home/CreatePet.cshtml

@@ -18,13 +18,13 @@
 			<input type="text" name="type" id="type" />
 		</div>
 	</div>
-		<div class="row">
+	<div class="row">
 		<div class="col-4">Порода:</div>
 		<div class="col-8">
 			<input type="text" name="breed" id="breed" />
 		</div>
 	</div>
-		<div class="row">
+	<div class="row">
 		<div class="col-4">Пол:</div>
 		<div class="col-8">
 			<input type="text" name="gender" id="gender" />

VeterinaryView/VeterinaryShowOwnerApp/Views/Home/CreatePurchase.cshtml

@@ -1,6 +1,56 @@
-namespace VeterinaryShowOwnerApp.Views.Home
-{
-    public class CreatePurchase
-    {
-    }
+@{
+	ViewData["Title"] = "CreatePurchase";
 }
+
+<div class="text-center">
+	<h2 class="display-4">Создание покупки</h2>
+</div>
+<form method="post">
+	<div class="row">
+		<div class="col-4">Лекарство:</div>
+		<div class="col-8">
+			<select id="drug" name="drug" class="form-control" asp-items="@(new SelectList(@ViewBag.Drugs,"Id", "DrugName"))"></select>
+		</div>
+	</div>
+	<div class="row">
+		<div class="col-4">Количество:</div>
+		<div class="col-8">
+			<input type="text" name="count" id="count" />
+		</div>
+	</div>
+	<div class="row">
+		<div class="col-4">Сумма:</div>
+		<div class="col-8">
+			<input type="text" id="sum" name="sum" readonly />
+		</div>
+	</div>
+	<div class="row">
+		<div class="col-8"></div>
+		<div class="col-4">
+			<input type="submit" value="Создать" class="btn btn-primary" />
+		</div>
+	</div>
+</form>
+<script>
+	$('#drug').on('change', function () {
+		check();
+	});
+	$('#count').on('change', function () {
+		check();
+	});
+
+	function check() {
+		var count = $('#count').val();
+		var drug = $('#drug').val();
+		if (count && drug) {
+			$.ajax({
+				method: "POST",
+				url: "/Home/Calc",
+				data: { count: count, drug: drug },
+				success: function (result) {
+					$("#sum").val(result);
+				}
+			});
+		};
+	}
+</script>

VeterinaryView/VeterinaryShowOwnerApp/Views/Home/DeletePet.cshtml

@@ -1,4 +1,4 @@
-@{
+n@{
 	ViewData["Title"] = "DeletePet";
 }
 <div class="text-center">

VeterinaryView/VeterinaryShowOwnerApp/appsettings.json

@@ -6,5 +6,5 @@
     }
   },
   "AllowedHosts": "*",
-  "IPAddress": "http://localhost:"
+  "IPAddress": "http://localhost:5156/"
 }