07 - WriteHooks & Validators

Docs / Samples / 07 - WriteHooks & Validators

Use write hooks and validators to control component writes and validate values.

Prerequisites

• .NET SDK 8.0+ or Unity 2021.3+
• ZenECS Core package installed
• Understanding of Write Hooks & Validators

Run It

.NET Standalone

cd Packages/com.zenecs.core/Samples~/07-WriteHooksValidators
dotnet run

Unity

1. Open Unity project
2. Open scene: Packages/com.zenecs.core/Samples~/07-WriteHooksValidators/Scene.unity
3. Press Play

Code Walkthrough

Write Permission Hook

Control component write permissions:

world.Hooks.AddWritePermission((entity, componentType) =>
{
    // Custom permission logic
    if (componentType == typeof(AdminComponent))
    {
        return world.HasComponent<Admin>(entity);
    }
    return true;
});

Value Validator

Validate component values before write:

world.Hooks.AddValidator<Health>(health =>
{
    // Validate health is within bounds
    return health.Current >= 0 && 
           health.Current <= health.Max &&
           health.Max > 0;
});

Complete Example

using ZenECS.Core;

var world = kernel.CreateWorld(null, "GameWorld");

// Permission hook: Only admins can modify admin components
world.Hooks.AddWritePermission((entity, componentType) =>
{
    if (componentType == typeof(AdminComponent))
    {
        return world.HasComponent<Admin>(entity);
    }
    return true;
});

// Validator: Ensure health is valid
world.Hooks.AddValidator<Health>(health =>
{
    if (health.Current < 0)
        return false;
    if (health.Current > health.Max)
        return false;
    if (health.Max <= 0)
        return false;
    return true;
});

// Test permissions
Entity player;
using (var cmd = world.BeginWrite())
{
    player = cmd.CreateEntity();
    cmd.AddComponent(player, new Health(100, 100));
}

// This will be validated
world.ReplaceComponent(player, new Health(150, 100));  // Invalid: exceeds max

// This will be allowed
world.ReplaceComponent(player, new Health(50, 100));  // Valid

See Also

• Write Hooks & Validators - Detailed documentation
• World Hook - Hook system
• Advanced Topics - Advanced patterns