Dynamic Form Generation

In this lesson, you will learn how to architect a form-builder engine in Blazor that dynamically renders UI controls based on a JSON schema, decoupling your UI from hardcoded markup.

The Core Concept: Schema-Driven UI

Instead of manually writing <input> tags for every form, we treat the form structure as data. By defining a schema—a collection of field objects containing properties like FieldType, Label, and ValidationRules—we can iterate through this collection at runtime and render the appropriate component for each entry.

Implementation Strategy

To achieve this, we use a DynamicField model and the DynamicComponent or a switch statement to decide which Blazor component (e.g., TextField, Checkbox, Dropdown) to render.

// The schema definition
public class FormField {
    public string Name { get; set; }
    public string Type { get; set; } // "text", "number", "checkbox"
    public string Label { get; set; }
}

// In your Razor component
@foreach (var field in schema)
{
    <div class="form-group">
        <label>@field.Label</label>
        @switch (field.Type)
        {
            case "text":
                <input @bind="formData[field.Name]" class="form-control" />
                break;
            case "checkbox":
                <input type="checkbox" @bind="formData[field.Name]" />
                break;
        }
    </div>
}

Why This Matters

By building an engine rather than a static form, you enable your application to adapt to changing business requirements without recompiling the frontend. When a new field is needed (e.g., a "Middle Name" field), you simply update the JSON metadata stored in your database, and the UI updates automatically across all clients. This is particularly powerful in multi-tenant environments where different clients may require unique data collection fields.

For advanced implementations, you would pair this with a Dictionary<string, object> to store the form data, allowing you to bind any number of dynamic fields to a single underlying model.

Key Takeaway: Dynamic form generation shifts your UI logic from static markup to data-driven metadata, allowing your application to evolve at the speed of your configuration files.