Validation in blazor| form validation in blazor c#| how to validate form in blazor c#

Validation in blazor| form validation in blazor c#| how to validate form in blazor c#

To validate a form in Blazor, you can utilize the built-in validation features provided by Blazor. Here's a step-by-step guide on how to perform form validation in Blazor:

1. Add the `EditForm` component: Wrap your form elements inside an `<EditForm>` component. This component provides form validation functionality and tracks the form's state.

   razor

   <EditForm Model="@formData" OnValidSubmit="@HandleSubmit">

       <!-- Form elements here -->

   </EditForm>

  

2. Define a model for form data: Create a class to represent the data structure of your form. Add validation attributes to the properties of this class to define the validation rules.

  csharp

   public class MyFormData

   {

       [Required(ErrorMessage = "Name is required.")]

       public string Name { get; set; }

       [EmailAddress(ErrorMessage = "Invalid email address.")]

       public string Email { get; set; }

   }

   

3. Bind form elements to the model properties: Use the `@bind` directive to bind form elements to the corresponding properties of the form data model.

   razor

   <div class="form-group">

       <label for="name">Name:</label>

       <input type="text" id="name" class="form-control" @bind="@formData.Name" />

       <ValidationMessage For="@(() => formData.Name)" />

   </div>

   <div class="form-group">

       <label for="email">Email:</label>

       <input type="email" id="email" class="form-control" @bind="@formData.Email" />

       <ValidationMessage For="@(() => formData.Email)" />

   </div>

   

   The `@bind` directive establishes a two-way binding between the input element and the corresponding property of the form data model. The `<ValidationMessage>` component is used to display validation error messages for each form element.

4. Handle form submission: Add a method to handle form submission. This method will be called when the form is validly submitted.

   csharp

   public void HandleSubmit()

   {

       if (editContext.Validate())

       {

           // Form is valid, perform the necessary actions

           // You can access the form data via the formData property

       }

       else

       {

           // Form is not valid, handle validation errors

       }

   }

   

   The `Validate()` method is called on the `EditContext` object to validate the form. If the form is valid, you can proceed with the desired actions. Otherwise, you can handle the validation errors appropriately.

5. Add validation styling (optional): You can add CSS styles to highlight validation errors visually. By default, Blazor adds the `validation-error` class to elements with validation errors.

   css

   .validation-error {

       border-color: red;

   }

   

With these steps, you have implemented form validation in Blazor. When the form is submitted, Blazor will perform client-side validation based on the defined validation attributes. Any validation errors will be displayed next to the corresponding form elements, allowing users to correct the errors before submitting the form.

Thanks for learning. Happy learning..

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