How do I force a redraw or re-render of a Blazor component?
Using the StateHasChanged() method, you can force a re-render of your Blazor component. The StateHasChanged() method notifies that the state has been changed and requires a re-render of the component. Refer to this link for more details.
How do I apply custom CSS style to a Blazor component?
To apply custom CSS style to a Blazor component, create a custom CSS file in your Razor page with the name of razorpage.css (i.e. Index.razor.css) and add your styles. [Index.razor.css] You can also define the custom CSS styles in the <style> section of Razor pages. [Index.razor]
How do I resolve the error “The type arguments for method ‘TypeInference.CreateListViewTemplates_4<TValue>(RenderTreeBuilder, int, int, RenderFragment<TValue>)’ cannot be inferred from the usage. Try specifying the type arguments explicitly”?
This error would occur when the generic Blazor component is unable to infer the type argument from the parameters. So, the compiler does not know which type of argument is intended. To resolve this, provide the intended type parameter explicitly. Refer to this link for more details.
How do I resolve the error “There was an unhandled exception on the current circuit, so this circuit will be terminated. For more information, turn on detailed exceptions in ‘CircuitOptions.DetailedErrors’.”?
To resolve and get more information about the error, enable the ‘CircuitOptions.DetailedErrors’ configuration in the ConfigureServices method in Startup.cs file. [Startup.cs] For the debug and development environment, initialize the IWebHostEnvironment and provide the web hosting environment information to the Startup constructor. Finally, add the AddCircuitOption configuration to the ConfigureServices method in the Startup.cs file. [Startup.cs]
How do I create and use a custom validation component?
To create a custom validation component in Blazor, follow these code steps: Create a Blazor Server or WebAssembly application and install the System.ComponentModel.Annotations NuGet package using NuGet Package Manager. Now, create a new custom validation class in the Pages folder and restrict the user to enter only “admin” in the password field.[CustomValidatorAttribute.cs] using System.ComponentModel.DataAnnotations; namespace {{Your_App_Name}}.Pages{ public class CustomValidationAttribute : ValidationAttribute { public string? ValidUserName { get; set; } protected override ValidationResult? IsValid ( object? username, ValidationContext validationContext ) { var content = username?.ToString()?.ToLower(); if (content!.Equals(ValidUserName?.ToLower())) { return null; } return new ValidationResult(ErrorMessage, new[] { validationContext.MemberName }); } }} Use the created custom validator attribute in the Razor component. Provide the error message and valid username properties for validation.[Index.razor] @page “/”@using System.ComponentModel.DataAnnotations <EditForm style=”width:470px;” Model=”_login” OnValidSubmit=”Submit”> <DataAnnotationsValidator /> <div class=”form-group row”> <label for=”name” class=”col-md-2 col-form-label”>Name:</label> <div class=”col-md-10″> <InputText id=”name” class=”form-control” @bind-Value=”_login.UserName” /> <ValidationMessage For=”@(() => _login.UserName)” /> </div> </div> <div class=”form-group row”> <label for=”supplier” class=”col-md-2 col-form-label”>Password:</label> <div class=”col-md-10″> <InputText id=”supplier” class=”form-control” @bind-Value=”_login.Password” /> <ValidationMessage For=”@(() => _login.Password)” /> </div> </div> <div class=”row”> <div class=”col-md-12 text-right”> <button type=”submit” class=”btn btn-success”>Submit</button> </div> </div> </EditForm> @code { private Login _login = new Login(); public void Submit() { Console.WriteLine($”User name is {_login.UserName} and password is {_login.Password}”); } public class Login { [Required] [CustomValidation(ErrorMessage = “The entered username is wrong “, ValidUserName = “admin”)] public string? UserName { get; set; } [Required] public string? Password { get; set; } } } Refer to the following output image for the custom validator.Refer to this link for more details. View Sample in GitHub
