Update EditForm for server edit with data annotations.

ServerManagement/Components/Pages/EditServer.razor

@@ -7,7 +7,9 @@
 
 @if (server != null)
 {
-  <EditForm Model="server" FormName="formServer" OnSubmit="SubmitServer">
+  <EditForm Model="server" FormName="formServer" OnValidSubmit="SubmitServer">
+    <DataAnnotationsValidator></DataAnnotationsValidator>
+    <ValidationSummary></ValidationSummary>
     <InputNumber @bind-Value="server.Id" hidden></InputNumber>
     <div class="row mb-3">
       <div class="col-2">
@@ -16,7 +18,11 @@
       <div class="col-6">
         <InputText @bind-Value="server.Name" class="form-control"></InputText>
       </div>
+      <div class="col">
+        <ValidationMessage For="() => server.Name"></ValidationMessage>
+      </div>
     </div>
+
     <div class="row mb-3">
       <div class="col-2">
         <label class="col-form-label">City</label>
@@ -24,6 +30,9 @@
       <div class="col-6">
         <InputText @bind-Value="server.City" class="form-control"></InputText>
       </div>
+      <div class="col">
+        <ValidationMessage For="() => server.City"></ValidationMessage>
+      </div>
     </div>
     <div class="row mb-3">
       <div class="col-2">

ServerManagement/Models/Server.cs

@@ -1,3 +1,6 @@
+using System.ComponentModel.DataAnnotations;
+// Data annotations: https://learn.microsoft.com/en-us/dotnet/api/system.componentmodel.dataannotations?view=net-9.0
+
 namespace ServerManagement.Models
 {
   public class Server
@@ -11,7 +14,11 @@ namespace ServerManagement.Models
 
     public int Id { get; set; }
     public bool IsOnline { get; set; }
+
+    [Required]
     public string? Name { get; set; }
+
+    [Required]
     public string? City { get; set; }
   }
 }