Form Validation Using Validator Component in ASP.NET Blazor

public class CustomValidator : ComponentBase
{
    private ValidationMessageStore messageStore;
    [CascadingParameter] public EditContext CurrentEditContext { get; set; }

    protected override void OnInitialized()
    {
        if (CurrentEditContext == null)
        {
            throw new InvalidOperationException(
                "To use validator component your razor page should have the edit component");
        }

        messageStore = new ValidationMessageStore(CurrentEditContext);
        
        // Clear Error Message On Raise Of OnValidationRequested Form Event
        CurrentEditContext.OnValidationRequested += (s, e) => messageStore.Clear();
        
        // Clear Error Message On Input Field Change Event
        CurrentEditContext.OnFieldChanged += (s, e) => messageStore.Clear(e.FieldIdentifier);
    }

    public void DisplayErrors(Dictionary<string, List<string>> errors)
    {
        foreach (var error in errors)
        {
            messageStore.Add(CurrentEditContext.Field(error.Key), error.Value);
        }

        CurrentEditContext.NotifyValidationStateChanged();
    }

    public void DisplayErrors(string fieldName, List<string> errors)
    {
        foreach (var error in errors)
        {
            messageStore.Add(CurrentEditContext.Field(fieldName), error);
        }

        CurrentEditContext.NotifyValidationStateChanged();
    }
}

App.razor

<EditForm Model="@_model" OnValidSubmit="ValidSubmit">
        <DataAnnotationsValidator/>
        <ValidationSummary/>
        <CustomValidator @ref="_customValidator"></CustomValidator>
...
@code {

    private CustomValidator _customValidator;

...
private async Task ValidSubmit(EditContext obj)
   {
       if (await CheckValidations())
       {
           if (OnSubmit.HasDelegate)
           {
               Customer.Customerr = _model.Customer.TrimText();
               Customer.ProvinceUUID = _model.ProvinceUUID;
               Customer.CityUUID = _model.CityUUID;

               await OnSubmit.InvokeAsync(new NewCustomerInfoEventArgs()
               {
                   Customer = Customer,
               });
           }
       }
   }

   private async Task<bool> CheckValidations()
   {
       int errors = 0;
       ApplicationDbContext context = await DbFactory.CreateDbContextAsync();
       var customer = _model.Customer.TrimText();
       var isExist = await context.DcCustomers.AnyAsync(x => x.Customerr == customer);
       await context.DisposeAsync();
       if (isExist)
       {
           _customValidator.DisplayErrors(nameof(_model.Customer), new List<string> { "نام مشتری تکراری است" });
           errors += 1;
       }

       if (errors == 0)
       {
           return true;
       }
       
       return false;
   }

References
https://www.learmoreseekmore.com/2021/01/blazor-server-forms-validator-component.html

Route Constraints in ASP.NET Core Blazor

@page "/route-parameter/{text?}"

<h1>Blazor is @Text!</h1>

@code {
    [Parameter]
    public string? Text { get; set; }

    protected override void OnInitialized()
    {
        Text = Text ?? "fantastic";
    }
}
@page "/user/{Id:int}/{Option:bool?}"

<p>
    Id: @Id
</p>

<p>
    Option: @Option
</p>

@code {
    [Parameter]
    public int Id { get; set; }

    [Parameter]
    public bool Option { get; set; }
}
Constraint Example Example Matches Invariant
culture
matching
bool {active:bool} trueFALSE No
datetime {dob:datetime} 2016-12-312016-12-31 7:32pm Yes
decimal {price:decimal} 49.99-1,000.01 Yes
double {weight:double} 1.234-1,001.01e8 Yes
float {weight:float} 1.234-1,001.01e8 Yes
guid {id:guid} CD2C1638-1638-72D5-1638-DEADBEEF1638{CD2C1638-1638-72D5-1638-DEADBEEF1638} No
int {id:int} 123456789-123456789 Yes
long {ticks:long} 123456789-123456789 Yes

References
https://learn.microsoft.com/en-us/aspnet/core/blazor/fundamentals/routing?view=aspnetcore-7.0#route-constraints

Blazor Custom Form Validation

If we have a validation requirement that cannot be implemented using the built-in attributes, we can create a custom validation attribute.

  1. Create a class that derives from the built-in abstract ValidationAttribute class and override IsValid() method.
  2. IsValid() method returns null if there are no validation errors, otherwise a ValidationResult object.
  3. ValidationResult accepts 2 parameters – Validation error message and the property name with which this validation error message must be associated with.
using System.ComponentModel.DataAnnotations;

namespace EmployeeManagement.Models.CustomValidators
{
    public class EmailDomainValidator : ValidationAttribute
    {
        public string AllowedDomain { get; set; }

        protected override ValidationResult IsValid(object value, 
            ValidationContext validationContext)
        {
            string[] strings = value.ToString().Split('@');
            if (strings[1].ToUpper() == AllowedDomain.ToUpper())
            {
                return null;
            }

            return new ValidationResult($"Domain must be {AllowedDomain}",
            new[] { validationContext.MemberName });
        }
    }
}
public class Employee
{
    [EmailDomainValidator(AllowedDomain = "pragimtech.com")]
    public string Email { get; set; }
}

References
https://www.pragimtech.com/blog/blazor/blazor-custom-form-validation/

Install Qt 6 using MSYS2

pacman -Syu
pacman -S base-devel
pacman -S mingw-w64-x86_64-qt-creator
pacman -S mingw-w64-x86_64-qt6-base
pacman -S mingw-w64-x86_64-qt6
pacman -S mingw-w64-x86_64-clang
pacman -S mingw-w64-clang-x86_64-toolchain
pacman -S mingw-w64-x86_64-clang-tools-extra
pacman -S mingw-w64-x86_64-gdb

Optional Dependencies:

pacman -S mingw-w64-x86_64-cmake
pacman -S mingw-w64-x86_64-gdb
pacman -S mingw-w64-x86_64-ninja
pacman -S mingw-w64-x86_64-qbs
pacman -S mingw-w64-x86_64-qt6-doc
pacman -S mingw-w64-x86_64-qt6-quicktimeline
pacman -S mingw-w64-clang-x86_64-tidy

References
https://wiki.qt.io/MSYS2
https://packages.msys2.org/package/mingw-w64-x86_64-qt-creator
https://packages.msys2.org/package/mingw-w64-x86_64-qt6-base
https://packages.msys2.org/group/mingw-w64-x86_64-qt6
https://packages.msys2.org/package/mingw-w64-x86_64-clang
https://packages.msys2.org/group/mingw-w64-clang-x86_64-toolchain
https://packages.msys2.org/package/mingw-w64-x86_64-clang-tools-extra
https://packages.msys2.org/package/mingw-w64-x86_64-gdb
https://packages.msys2.org/package/mingw-w64-clang-x86_64-tidy?repo=clang64