diff --git a/UserService.DatabaseLayer/DataModels/ModelBuilderExtensions.cs b/UserService.DatabaseLayer/DataModels/ModelBuilderExtensions.cs
index 68710ae..e2be228 100644
--- a/UserService.DatabaseLayer/DataModels/ModelBuilderExtensions.cs
+++ b/UserService.DatabaseLayer/DataModels/ModelBuilderExtensions.cs
@@ -1,6 +1,7 @@
 using System;
 using Microsoft.EntityFrameworkCore;
 using System.Collections.Generic;
+using UserService.Infrastructure.DataModels;
 
 namespace UserService.DatabaseLayer.DataModels
 {
diff --git a/UserService.DatabaseLayer/DataModels/Node.cs b/UserService.DatabaseLayer/DataModels/Node.cs
deleted file mode 100644
index ed5c873..0000000
--- a/UserService.DatabaseLayer/DataModels/Node.cs
+++ /dev/null
@@ -1,62 +0,0 @@
-#nullable enable
-using System;
-using System.Collections.Generic;
-using System.ComponentModel.DataAnnotations;
-
-namespace UserService.DatabaseLayer.DataModels
-{
-    public class OrganizationUnit : Node
-    {
-        public Member? Manager { get; set; }
-    }
-
-    public class SecurityGroup : Member
-    {
-    }
-
-    public class User : Member
-    {
-        public string? FirstName { get; set; }
-        public string? LastName { get; set; }
-        public bool IsActive { get; set; }
-
-        public string FullName => $"{FirstName} {LastName}";
-
-        public IEnumerable<UserMember> MemberOf { get; set; } = new List<UserMember>();
-    }
-
-    public class UserMember
-    {
-        public int MemberId { get; set; }
-        public Member? Member { get; set; }
-
-        public int UserId { get; set; }
-
-        public User? User { get; set; }
-    }
-
-    public abstract class Member : Node
-    {
-        [EmailAddress]
-        public string? EMail { get; set; }
-
-        public ICollection<UserMember> Members { get; set; } = new List<UserMember>();
-    }
-
-    public abstract class Node : ICloneable
-    {
-        public int Id { get; set; }
-        [Required] public string CommonName { get; set; } = null!;
-        public string? Description { get; set; }
-        public ICollection<Node> Children { get; set; } = new List<Node>();
-        public Node? Parent { get; set; } //Parent
-        public int? ParentId { get; set; }
-
-        public override string ToString() => CommonName;
-
-        public int Level => Parent?.Level + 1 ?? 0;
-
-        /// <inheritdoc />
-        public virtual object Clone() => MemberwiseClone();
-    }
-}
\ No newline at end of file
diff --git a/UserService.DatabaseLayer/DataModels/UserServiceDbContext.cs b/UserService.DatabaseLayer/DataModels/UserServiceDbContext.cs
index 68c5567..cd9e5d8 100644
--- a/UserService.DatabaseLayer/DataModels/UserServiceDbContext.cs
+++ b/UserService.DatabaseLayer/DataModels/UserServiceDbContext.cs
@@ -1,4 +1,5 @@
 using Microsoft.EntityFrameworkCore;
+using UserService.Infrastructure.DataModels;
 
 namespace UserService.DatabaseLayer.DataModels
 {
diff --git a/UserService.DatabaseLayer/Migrations/UserServiceDbContextModelSnapshot.cs b/UserService.DatabaseLayer/Migrations/UserServiceDbContextModelSnapshot.cs
index 4d03a6e..c9aa074 100644
--- a/UserService.DatabaseLayer/Migrations/UserServiceDbContextModelSnapshot.cs
+++ b/UserService.DatabaseLayer/Migrations/UserServiceDbContextModelSnapshot.cs
@@ -1,8 +1,7 @@
 // <auto-generated />
-using System;
+
 using Microsoft.EntityFrameworkCore;
 using Microsoft.EntityFrameworkCore.Infrastructure;
-using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
 using UserService.DatabaseLayer.DataModels;
 
 namespace UserService.DatabaseLayer.Migrations
diff --git a/UserService.DatabaseLayer/Repository/BaseRepository.cs b/UserService.DatabaseLayer/Repository/BaseRepository.cs
index b50f2ee..61db729 100644
--- a/UserService.DatabaseLayer/Repository/BaseRepository.cs
+++ b/UserService.DatabaseLayer/Repository/BaseRepository.cs
@@ -7,6 +7,7 @@ using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.EntityFrameworkCore;
 using UserService.DatabaseLayer.DataModels;
+using UserService.Infrastructure.DataModels;
 
 namespace UserService.DatabaseLayer.Repository
 {
diff --git a/UserService.DatabaseLayer/Repository/IRepository.cs b/UserService.DatabaseLayer/Repository/IRepository.cs
index 5a95ac4..74058e5 100644
--- a/UserService.DatabaseLayer/Repository/IRepository.cs
+++ b/UserService.DatabaseLayer/Repository/IRepository.cs
@@ -4,7 +4,7 @@ using System.Collections.Generic;
 using System.Linq.Expressions;
 using System.Threading;
 using System.Threading.Tasks;
-using UserService.DatabaseLayer.DataModels;
+using UserService.Infrastructure.DataModels;
 
 namespace UserService.DatabaseLayer.Repository
 {
diff --git a/UserService.DatabaseLayer/Repository/OrganizationUnitsRepository.cs b/UserService.DatabaseLayer/Repository/OrganizationUnitsRepository.cs
index 7a1fa41..fa44e7c 100644
--- a/UserService.DatabaseLayer/Repository/OrganizationUnitsRepository.cs
+++ b/UserService.DatabaseLayer/Repository/OrganizationUnitsRepository.cs
@@ -6,6 +6,7 @@ using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.EntityFrameworkCore;
 using UserService.DatabaseLayer.DataModels;
+using UserService.Infrastructure.DataModels;
 
 namespace UserService.DatabaseLayer.Repository
 {
diff --git a/UserService.DatabaseLayer/Repository/SecurityGroupsRepository.cs b/UserService.DatabaseLayer/Repository/SecurityGroupsRepository.cs
index 0f4ce54..6948ce7 100644
--- a/UserService.DatabaseLayer/Repository/SecurityGroupsRepository.cs
+++ b/UserService.DatabaseLayer/Repository/SecurityGroupsRepository.cs
@@ -1,4 +1,4 @@
-using UserService.DatabaseLayer.DataModels;
+using UserService.Infrastructure.DataModels;
 
 namespace UserService.DatabaseLayer.Repository
 {
diff --git a/UserService.DatabaseLayer/Repository/UsersRepository.cs b/UserService.DatabaseLayer/Repository/UsersRepository.cs
index 95421ca..cb60251 100644
--- a/UserService.DatabaseLayer/Repository/UsersRepository.cs
+++ b/UserService.DatabaseLayer/Repository/UsersRepository.cs
@@ -1,4 +1,4 @@
-using UserService.DatabaseLayer.DataModels;
+using UserService.Infrastructure.DataModels;
 
 namespace UserService.DatabaseLayer.Repository
 {
diff --git a/UserService.DatabaseLayer/UserService.DatabaseLayer.csproj b/UserService.DatabaseLayer/UserService.DatabaseLayer.csproj
index fc60665..6bd1a27 100644
--- a/UserService.DatabaseLayer/UserService.DatabaseLayer.csproj
+++ b/UserService.DatabaseLayer/UserService.DatabaseLayer.csproj
@@ -2,7 +2,7 @@
 
     <PropertyGroup>
         <TargetFramework>netcoreapp3.1</TargetFramework>
-        <LangVersion>8</LangVersion>
+        <LangVersion>latest</LangVersion>
         <Nullable>enable</Nullable>
     </PropertyGroup>
 
@@ -18,4 +18,8 @@
       <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="3.1.7" />
     </ItemGroup>
 
+    <ItemGroup>
+      <ProjectReference Include="..\UserService.Infrastructure\UserService.Infrastructure.csproj" />
+    </ItemGroup>
+
 </Project>
diff --git a/UserService.Infrastructure/DataModels/Member.cs b/UserService.Infrastructure/DataModels/Member.cs
new file mode 100644
index 0000000..ee4a4cc
--- /dev/null
+++ b/UserService.Infrastructure/DataModels/Member.cs
@@ -0,0 +1,13 @@
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+
+namespace UserService.Infrastructure.DataModels
+{
+    public abstract class Member : Node
+    {
+        [EmailAddress]
+        public string? EMail { get; set; }
+
+        public ICollection<UserMember> Members { get; set; } = new List<UserMember>();
+    }
+}
\ No newline at end of file
diff --git a/UserService.Infrastructure/DataModels/Node.cs b/UserService.Infrastructure/DataModels/Node.cs
new file mode 100644
index 0000000..6bbb3c0
--- /dev/null
+++ b/UserService.Infrastructure/DataModels/Node.cs
@@ -0,0 +1,24 @@
+#nullable enable
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+
+namespace UserService.Infrastructure.DataModels
+{
+    public abstract class Node : ICloneable
+    {
+        public int Id { get; set; }
+        [Required] public string CommonName { get; set; } = null!;
+        public string? Description { get; set; }
+        public ICollection<Node> Children { get; set; } = new List<Node>();
+        public Node? Parent { get; set; } //Parent
+        public int? ParentId { get; set; }
+
+        public override string ToString() => CommonName;
+
+        public int Level => Parent?.Level + 1 ?? 0;
+
+        /// <inheritdoc />
+        public virtual object Clone() => MemberwiseClone();
+    }
+}
\ No newline at end of file
diff --git a/UserService.Infrastructure/DataModels/OrganizationUnit.cs b/UserService.Infrastructure/DataModels/OrganizationUnit.cs
new file mode 100644
index 0000000..405278a
--- /dev/null
+++ b/UserService.Infrastructure/DataModels/OrganizationUnit.cs
@@ -0,0 +1,7 @@
+namespace UserService.Infrastructure.DataModels
+{
+    public class OrganizationUnit : Node
+    {
+        public Member? Manager { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/UserService.Infrastructure/DataModels/SecurityGroup.cs b/UserService.Infrastructure/DataModels/SecurityGroup.cs
new file mode 100644
index 0000000..78d3a91
--- /dev/null
+++ b/UserService.Infrastructure/DataModels/SecurityGroup.cs
@@ -0,0 +1,6 @@
+namespace UserService.Infrastructure.DataModels
+{
+    public class SecurityGroup : Member
+    {
+    }
+}
\ No newline at end of file
diff --git a/UserService.Infrastructure/DataModels/User.cs b/UserService.Infrastructure/DataModels/User.cs
new file mode 100644
index 0000000..a7f458e
--- /dev/null
+++ b/UserService.Infrastructure/DataModels/User.cs
@@ -0,0 +1,15 @@
+using System.Collections.Generic;
+
+namespace UserService.Infrastructure.DataModels
+{
+    public class User : Member
+    {
+        public string? FirstName { get; set; }
+        public string? LastName { get; set; }
+        public bool IsActive { get; set; }
+
+        public string FullName => $"{FirstName} {LastName}";
+
+        public IEnumerable<UserMember> MemberOf { get; set; } = new List<UserMember>();
+    }
+}
\ No newline at end of file
diff --git a/UserService.Infrastructure/DataModels/UserMember.cs b/UserService.Infrastructure/DataModels/UserMember.cs
new file mode 100644
index 0000000..91d4f69
--- /dev/null
+++ b/UserService.Infrastructure/DataModels/UserMember.cs
@@ -0,0 +1,12 @@
+namespace UserService.Infrastructure.DataModels
+{
+    public class UserMember
+    {
+        public int MemberId { get; set; }
+        public Member? Member { get; set; }
+
+        public int UserId { get; set; }
+
+        public User? User { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/UserService.Infrastructure/UserService.Infrastructure.csproj b/UserService.Infrastructure/UserService.Infrastructure.csproj
new file mode 100644
index 0000000..551862b
--- /dev/null
+++ b/UserService.Infrastructure/UserService.Infrastructure.csproj
@@ -0,0 +1,12 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>netstandard2.0</TargetFramework>
+    <LangVersion>latest</LangVersion>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="System.ComponentModel.Annotations" Version="4.3.0" />
+  </ItemGroup>
+
+</Project>
diff --git a/UserService.Infrastructure/Validators.cs b/UserService.Infrastructure/Validators.cs
new file mode 100644
index 0000000..5eabcf6
--- /dev/null
+++ b/UserService.Infrastructure/Validators.cs
@@ -0,0 +1,22 @@
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+using System.Linq;
+using UserService.Infrastructure.DataModels;
+
+namespace UserService.Infrastructure
+{
+    public static class Validators
+    {
+        public static bool? ValidateEmail(string mailAddress)
+        {
+            if (string.IsNullOrEmpty(mailAddress)) return null;
+            return new EmailAddressAttribute().IsValid(mailAddress);
+        }
+
+        public static bool? ValidateCommonName(string commonName, IReadOnlyList<User> users)
+        {
+            if (string.IsNullOrEmpty(commonName)) return false;
+            return users.All(x => x.CommonName != commonName);
+        }
+    }
+}
diff --git a/UserService.Test/UnitTest1.cs b/UserService.Test/UnitTest1.cs
index 0b70fc3..8fc8774 100644
--- a/UserService.Test/UnitTest1.cs
+++ b/UserService.Test/UnitTest1.cs
@@ -5,6 +5,7 @@ using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
 using UserService.DatabaseLayer.DataModels;
+using UserService.Infrastructure.DataModels;
 
 namespace UserService.Test
 {
diff --git a/UserService.Test/UserService.Test.csproj b/UserService.Test/UserService.Test.csproj
index 48b2f52..c20cbd9 100644
--- a/UserService.Test/UserService.Test.csproj
+++ b/UserService.Test/UserService.Test.csproj
@@ -4,6 +4,8 @@
     <TargetFramework>netcoreapp3.1</TargetFramework>
 
     <IsPackable>false</IsPackable>
+
+    <LangVersion>latest</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/UserService.db b/UserService.db
index 11403be..adc6bf4 100644
Binary files a/UserService.db and b/UserService.db differ
diff --git a/UserService.sln b/UserService.sln
index 3136372..6153a9d 100644
--- a/UserService.sln
+++ b/UserService.sln
@@ -14,6 +14,8 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution
 		.editorconfig = .editorconfig
 	EndProjectSection
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "UserService.Infrastructure", "UserService.Infrastructure\UserService.Infrastructure.csproj", "{586BD023-5C7B-4D9C-A17E-A0D5CEDADD20}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -32,6 +34,10 @@ Global
 		{4505C991-7E39-416F-94E5-D906DD0D90F9}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{4505C991-7E39-416F-94E5-D906DD0D90F9}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{4505C991-7E39-416F-94E5-D906DD0D90F9}.Release|Any CPU.Build.0 = Release|Any CPU
+		{586BD023-5C7B-4D9C-A17E-A0D5CEDADD20}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{586BD023-5C7B-4D9C-A17E-A0D5CEDADD20}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{586BD023-5C7B-4D9C-A17E-A0D5CEDADD20}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{586BD023-5C7B-4D9C-A17E-A0D5CEDADD20}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
diff --git a/UserService/Pages/Directory.razor.cs b/UserService/Pages/Directory.razor.cs
index 2e238b7..d7e6419 100644
--- a/UserService/Pages/Directory.razor.cs
+++ b/UserService/Pages/Directory.razor.cs
@@ -2,8 +2,8 @@
 using System.Linq;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Components;
-using UserService.DatabaseLayer.DataModels;
 using UserService.DatabaseLayer.Repository;
+using UserService.Infrastructure.DataModels;
 
 namespace UserService.Pages
 {
diff --git a/UserService/Pages/SecurityGroups.razor b/UserService/Pages/SecurityGroups.razor
index 21b50da..aef421f 100644
--- a/UserService/Pages/SecurityGroups.razor
+++ b/UserService/Pages/SecurityGroups.razor
@@ -1,5 +1,5 @@
 @page "/securitygroups"
-@using UserService.DatabaseLayer.DataModels
+@using UserService.Infrastructure.DataModels
 @inherits SecurityGroupsBase
 
 <h1>Table of all security groups</h1>
diff --git a/UserService/Pages/SecurityGroups.razor.cs b/UserService/Pages/SecurityGroups.razor.cs
index 1c65bfd..c1fcb06 100644
--- a/UserService/Pages/SecurityGroups.razor.cs
+++ b/UserService/Pages/SecurityGroups.razor.cs
@@ -1,8 +1,8 @@
 using System.Collections.Generic;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Components;
-using UserService.DatabaseLayer.DataModels;
 using UserService.DatabaseLayer.Repository;
+using UserService.Infrastructure.DataModels;
 
 namespace UserService.Pages
 {
diff --git a/UserService/Pages/Users.razor b/UserService/Pages/Users.razor
index 82bbe63..33c4612 100644
--- a/UserService/Pages/Users.razor
+++ b/UserService/Pages/Users.razor
@@ -1,5 +1,5 @@
 @page "/users"
-@using UserService.DatabaseLayer.DataModels
+@using UserService.Infrastructure.DataModels
 @inherits UsersBase
 
 <h1>List of all users</h1>
@@ -12,7 +12,9 @@
 }
 else
 {
-    <DataGrid TItem="User" RowSelectable="@(u => false)" Editable="true" EditMode="DataGridEditMode.Popup" RowRemoving="RowDeletingCallback" Data="@Users" RowInserted="RowInsertedCallback" RowUpdating="RowUpdatingCallback">
+    <TextEdit Placeholder="Search" Size="Size.Large" @bind-Text="@CustomFilterValue" />
+
+    <DataGrid TItem="User" RowSelectable="@(u => false)" CustomFilter="@OnCustomFilter" Sortable="true" Editable="true" EditMode="DataGridEditMode.Popup" RowRemoving="RowDeletingCallback" Data="@Users" RowInserted="RowInsertedCallback" RowInserting="RowInsertingCallback" RowUpdating="RowUpdatingCallback">
         <DataGridCommandColumn TItem="User">
             <NewCommandTemplate>
                 <Button Color="Color.Success" Clicked="@context.Clicked" title="Create user">
@@ -54,7 +56,7 @@ else
                 </Validation>
             </EditTemplate>
         </DataGridColumn>
-        <DataGridColumn TItem="User" Field="@nameof(User.FirstName)" Caption="First Name" Editable="true"/>
+        <DataGridColumn TItem="User" Field="@nameof(User.FirstName)" Caption="First Name" Editable="true" />
         <DataGridColumn TItem="User" Field="@nameof(User.LastName)" Caption="Last Name" Editable="true"/>
         <DataGridColumn TItem="User" Field="@nameof(User.EMail)" Caption="EMail" Editable="true">
             <EditTemplate>
@@ -78,17 +80,14 @@ else
 
             </DisplayTemplate>
             <EditTemplate>
-               
                     <Select TValue="int?" SelectedValue="@((int?)(context.CellValue))" SelectedValueChanged="@(v => context.CellValue = v)" >
                     @foreach (var item in OrganizationUnits)
                     {
                         <SelectItem TValue="int" Value="@(item.Id)">@item.CommonName</SelectItem>
                     }
                     </Select>
-                
-
             </EditTemplate>
         </DataGridSelectColumn>
-        <DataGridCheckColumn TItem="User" Field="@nameof(User.IsActive)" Caption="Active" Editable="true"/>
+        <DataGridCheckColumn TItem="User" Field="@nameof(User.IsActive)" Caption="Active" Editable="true" />
     </DataGrid>
 }
\ No newline at end of file
diff --git a/UserService/Pages/Users.razor.cs b/UserService/Pages/Users.razor.cs
index ff80935..78592c4 100644
--- a/UserService/Pages/Users.razor.cs
+++ b/UserService/Pages/Users.razor.cs
@@ -1,14 +1,14 @@
 using System;
 using Microsoft.AspNetCore.Components;
 using System.Collections.Generic;
-using System.ComponentModel.DataAnnotations;
 using System.Linq;
 using System.Threading.Tasks;
 using Blazorise;
 using Blazorise.DataGrid;
 using Microsoft.JSInterop;
-using UserService.DatabaseLayer.DataModels;
 using UserService.DatabaseLayer.Repository;
+using UserService.Infrastructure;
+using UserService.Infrastructure.DataModels;
 
 namespace UserService.Pages
 {
@@ -21,6 +21,7 @@ namespace UserService.Pages
 
         protected IReadOnlyList<User>? Users { get; private set; }
         protected IReadOnlyList<OrganizationUnit>? OrganizationUnits { get; private set; }
+        protected string? CustomFilterValue { get; set; }
 
         protected override async Task OnInitializedAsync()
         {
@@ -28,14 +29,24 @@ namespace UserService.Pages
             OrganizationUnits = await OrganizationUnitsRepository.GetAllAsync().ConfigureAwait(false);
         }
 
-        protected async Task RowInsertedCallback(SavedRowItem<User, Dictionary<string, object>> arg)
+        protected async Task RowInsertingCallback(CancellableRowChange<User, Dictionary<string, object>> arg)
         {
-            if (arg == null) throw new ArgumentNullException(nameof(arg));
-            var user = arg.Item;
-            user.ParentId = -2;
-            await UsersRepository.AddAsync(user).ConfigureAwait(false);
+            if (arg is null) throw new ArgumentNullException(nameof(arg));
+            var mailValidation = Validators.ValidateEmail(arg.Values[nameof(User.EMail)]?.ToString());
+            var commonNameValidation = Validators.ValidateCommonName(arg.Values[nameof(User.CommonName)]?.ToString(), Users);
+            if (mailValidation == true && commonNameValidation == true) return;
+
+            await JsRuntime.InvokeVoidAsync("alert", "User could not be added").ConfigureAwait(false);
+            arg.Cancel = true;
         }
 
+        protected async Task RowInsertedCallback(SavedRowItem<User, Dictionary<string, object>> arg)
+        {
+            if (arg is null) throw new ArgumentNullException(nameof(arg));
+            var user = arg.Item;
+            user.Parent = OrganizationUnits?.FirstOrDefault(x => x.Id == user.ParentId);
+            await UsersRepository.AddAsync(user).ConfigureAwait(false);
+        }
         protected async Task RowDeletingCallback(CancellableRowChange<User> arg)
         {
             if (arg == null) throw new ArgumentNullException(nameof(arg));
@@ -50,38 +61,46 @@ namespace UserService.Pages
             arg.Cancel = true;
         }
 
-        protected static void ValidateCommonName(ValidatorEventArgs e)
+        protected void ValidateCommonName(ValidatorEventArgs e)
         {
             if (e == null) throw new ArgumentNullException(nameof(e));
             var commonName = e.Value?.ToString();
-
-            if (string.IsNullOrEmpty(commonName))
-                e.Status = ValidationStatus.Error;
-            else
-                e.Status = ValidationStatus.Success;
+            var validationResult = Validators.ValidateCommonName(commonName, Users);
+            e.Status = validationResult == false ? ValidationStatus.Error : ValidationStatus.Success;
         }
 
         protected static void ValidateEmail(ValidatorEventArgs e)
         {
             if (e == null) throw new ArgumentNullException(nameof(e));
             var email = e.Value?.ToString();
+            var validationResult = Validators.ValidateEmail(email);
 
-            if (string.IsNullOrEmpty(email))
-                e.Status = ValidationStatus.None;
-            else if (!new EmailAddressAttribute().IsValid(email))
+            e.Status = validationResult switch
             {
-                e.Status = ValidationStatus.Error;
-            }
-            else
-                e.Status = ValidationStatus.Success;
+                null => ValidationStatus.None,
+                false => ValidationStatus.Error,
+                _ => ValidationStatus.Success
+            };
         }
         protected async Task RowUpdatingCallback(CancellableRowChange<User, Dictionary<string, object>> arg)
         {
             if (arg == null) throw new ArgumentNullException(nameof(arg));
             var user = arg.Item;
-            user.Parent = OrganizationUnits.FirstOrDefault(x => x.Id == (int?) arg.Values[nameof(Node.ParentId)]);
+            user.Parent = OrganizationUnits.FirstOrDefault(x => x.Id == (int?)arg.Values[nameof(Node.ParentId)]);
             var result = await UsersRepository.UpdateAsync(user).ConfigureAwait(false);
             arg.Cancel = !result;
         }
+
+        protected bool OnCustomFilter(User model)
+        {
+            // We want to accept empty value as valid or otherwise
+            // datagrid will not show anything.
+            if (string.IsNullOrEmpty(CustomFilterValue) || CustomFilterValue.Length < 3) return true;
+
+            return
+                model?.FirstName?.Contains(CustomFilterValue, StringComparison.OrdinalIgnoreCase) == true
+                || model?.LastName?.Contains(CustomFilterValue, StringComparison.OrdinalIgnoreCase) == true
+                || model?.CommonName?.Contains(CustomFilterValue, StringComparison.OrdinalIgnoreCase) == true;
+        }
     }
 }
\ No newline at end of file
diff --git a/UserService/UserService.csproj b/UserService/UserService.csproj
index 1bffdf8..c104d48 100644
--- a/UserService/UserService.csproj
+++ b/UserService/UserService.csproj
@@ -3,6 +3,7 @@
   <PropertyGroup>
     <TargetFramework>netcoreapp3.1</TargetFramework>
     <Nullable>enable</Nullable>
+    <LangVersion>latest</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>
@@ -11,6 +12,7 @@
 
   <ItemGroup>
     <ProjectReference Include="..\UserService.DatabaseLayer\UserService.DatabaseLayer.csproj" />
+    <ProjectReference Include="..\UserService.Infrastructure\UserService.Infrastructure.csproj" />
   </ItemGroup>
 
   <ItemGroup>