diff --git a/src/Forms/Container.php b/src/Forms/Container.php
index 28d8ad465..496f36bfc 100644
--- a/src/Forms/Container.php
+++ b/src/Forms/Container.php
@@ -26,7 +26,7 @@ class Container extends Nette\ComponentModel\Container implements \ArrayAccess
 
 	private const ARRAY = 'array';
 
-	/** @var callable[]&(callable(Container, mixed): void)[]; Occurs when the form is validated */
+	/** @var callable[]&((callable(Container, array|object|null): void)|(callable(array|object|null): void))[]; Occurs when the form was validated */
 	public $onValidate = [];
 
 	/** @var ControlGroup|null */
@@ -191,10 +191,15 @@ public function validate(array $controls = null): void
 		$isValid = !$this->getErrors();
 		foreach ($this->onValidate as $handler) {
 			$params = Nette\Utils\Callback::toReflection($handler)->getParameters();
-			$values = isset($params[1]) && $isValid
-				? $this->getValues($params[1]->getType() instanceof \ReflectionNamedType ? $params[1]->getType()->getName() : null)
-				: null;
-			$handler($this, $values);
+			$types = array_map([Nette\Utils\Reflection::class, 'getParameterType'], $params);
+			$handler(
+				!isset($types[0]) || $this instanceof $types[0]
+					? $this
+					: ($isValid ? $this->getValues($types[0]) : null),
+				isset($params[1]) && $isValid
+					? $this->getValues($types[1])
+					: null
+			);
 		}
 	}
 
diff --git a/src/Forms/Controls/SubmitButton.php b/src/Forms/Controls/SubmitButton.php
index 8d2346d81..02f40adf5 100644
--- a/src/Forms/Controls/SubmitButton.php
+++ b/src/Forms/Controls/SubmitButton.php
@@ -19,7 +19,7 @@
  */
 class SubmitButton extends Button implements Nette\Forms\SubmitterControl
 {
-	/** @var callable[]&(callable(SubmitButton): void)[]; Occurs when the button is clicked and form is successfully validated */
+	/** @var callable[]&((callable(Nette\Forms\Form|SubmitButton, array|object): void)|(callable(array|object): void))[]; Occurs when the button is clicked and form is successfully validated */
 	public $onClick = [];
 
 	/** @var callable[]&(callable(SubmitButton): void)[]; Occurs when the button is clicked and form is not validated */
diff --git a/src/Forms/Form.php b/src/Forms/Form.php
index 3f9c26400..5209a3e39 100644
--- a/src/Forms/Form.php
+++ b/src/Forms/Form.php
@@ -82,7 +82,7 @@ class Form extends Container implements Nette\HtmlStringable
 	/** @internal protection token ID */
 	public const PROTECTOR_ID = '_token_';
 
-	/** @var callable[]&(callable(Form, mixed): void)[]; Occurs when the form is submitted and successfully validated */
+	/** @var callable[]&((callable(Form, array|object): void)|(callable(array|object): void))[]; Occurs when the form is submitted and successfully validated */
 	public $onSuccess = [];
 
 	/** @var callable[]&(callable(Form): void)[]; Occurs when the form is submitted and is not valid */
@@ -443,10 +443,19 @@ private function invokeHandlers(iterable $handlers, $button = null): void
 	{
 		foreach ($handlers as $handler) {
 			$params = Nette\Utils\Callback::toReflection($handler)->getParameters();
-			$values = isset($params[1])
-				? $this->getValues($params[1]->getType() instanceof \ReflectionNamedType ? $params[1]->getType()->getName() : null)
-				: null;
-			$handler($button ?: $this, $values);
+			$types = array_map([Nette\Utils\Reflection::class, 'getParameterType'], $params);
+			if (!isset($types[0])) {
+				$arg0 = $button ?: $this;
+			} elseif ($this instanceof $types[0]) {
+				$arg0 = $this;
+			} elseif ($button instanceof $types[0]) {
+				$arg0 = $button;
+			} else {
+				$arg0 = $this->getValues($types[0]);
+			}
+			$arg1 = isset($params[1]) ? $this->getValues($types[1]) : null;
+			$handler($arg0, $arg1);
+
 			if (!$this->isValid()) {
 				return;
 			}
diff --git a/tests/Forms/Forms.callbackParameters.phpt b/tests/Forms/Forms.callbackParameters.phpt
index a0fea8abc..d3d780338 100644
--- a/tests/Forms/Forms.callbackParameters.phpt
+++ b/tests/Forms/Forms.callbackParameters.phpt
@@ -26,26 +26,26 @@ $types = [];
 
 // Test the closure second parameter to be an ArrayHash instance by default
 $f1 = function ($form, $values) use (&$types) {
-	$types[] = $form instanceof Form;
-	$types[] = $values instanceof ArrayHash;
+	$types['f1'][] = $form instanceof Form;
+	$types['f1'][] = $values instanceof ArrayHash;
 };
 
 // Test the closure second parameter to be an array by type-hint
 $f2 = function ($form, array $values) use (&$types) {
-	$types[] = $form instanceof Form;
-	$types[] = is_array($values);
+	$types['f2'][] = $form instanceof Form;
+	$types['f2'][] = is_array($values);
 };
 
 // Test the closure second parameter to be an ArrayHash instance by default
 $b1 = function ($form, $values) use (&$types) {
-	$types[] = $form instanceof SubmitButton;
-	$types[] = $values instanceof ArrayHash;
+	$types['b1'][] = $form instanceof SubmitButton;
+	$types['b1'][] = $values instanceof ArrayHash;
 };
 
 // Test the closure second parameter to be an array by type-hint
 $b2 = function ($form, array $values) use (&$types) {
-	$types[] = $form instanceof SubmitButton;
-	$types[] = is_array($values);
+	$types['b2'][] = $form instanceof SubmitButton;
+	$types['b2'][] = is_array($values);
 };
 
 // Test the second parameter in ArrayHash form to be immutable
@@ -57,10 +57,58 @@ $f5 = function ($form, $values) use (&$arrayHashIsImmutable) {
 	$arrayHashIsImmutable[] = $values->text === 'a';
 };
 
-$form->onSuccess = [$f1, $f2, $f1, $f4, $f5];
-$form->onValidate = [$f1, $f2, $f1, $f4, $f5];
-$form['btn']->onClick = [$b1, $b2, $b1, $f4, $f5];
+// Test the closure single parameter without type-hint
+$f6 = function ($form) use (&$types) {
+	$types['f6'][] = $form instanceof Form;
+};
+
+// Test the closure single array parameter
+$f7 = function (array $values) use (&$types) {
+	$types['f7'][] = is_array($values);
+};
+
+// Test the closure single Form-typed parameter
+$f8 = function (Form $values) use (&$types) {
+	$types['f8'][] = $values instanceof Form;
+};
+
+// Test the closure single not-Form-typed parameter
+$f9 = function (ArrayHash $values) use (&$types) {
+	$types['f9'][] = $values instanceof ArrayHash;
+};
+
+// Test the closure single parameter without type-hint
+$b3 = function ($form) use (&$types) {
+	$types['b3'][] = $form instanceof SubmitButton;
+};
+
+// Test the closure single array parameter
+$b4 = function (array $values) use (&$types) {
+	$types['b4'][] = is_array($values);
+};
+
+// Test the closure single parameter SubmitButton-typed
+$b5 = function (SubmitButton $form) use (&$types) {
+	$types['b5'][] = $form instanceof SubmitButton;
+};
+
+
+$form->onSuccess = [$f1, $f2, $f1, $f4, $f5, $f6, $f7, $f8, $f9];
+$form->onValidate = [$f1, $f2, $f1, $f4, $f5, $f6, $f7, $f8, $f9];
+$form['btn']->onClick = [$b1, $b2, $b1, $f4, $f5, $b3, $b4, $b5];
 $form->fireEvents();
 
-Assert::same([true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true], $types);
+Assert::same([
+	'f1' => [true, true, true, true, true, true, true, true],
+	'f2' => [true, true, true, true],
+	'f6' => [true, true],
+	'f7' => [true, true],
+	'f8' => [true, true],
+	'f9' => [true, true],
+	'b1' => [true, true, true, true],
+	'b2' => [true, true],
+	'b3' => [true],
+	'b4' => [true],
+	'b5' => [true],
+], $types);
 Assert::same([true, true, true], $arrayHashIsImmutable);