How to validate a child component that contains RadzenDropDown from parent component?

Radzen Studio Blazor Server
1

Hi,

I have one child component and one parent component. The child component contains two RadzenDropDown one is for category and one is for product. I want to validate the product.

Child component:-

<RadzenDropDown class="form-control" placeholder="Select Category"
                        AllowClear="true"
                        AllowFiltering="true"
                        Multiple="true"
                        FilterCaseSensitivity="FilterCaseSensitivity.CaseInsensitive"
                        TextProperty="Name"
                        ValueProperty="Id"
                    @bind-Value=@idCategory
                    Data = @_listCategory
                        Change=@(args => onProductsChange(args)) />

<RadzenDropDown class="form-control" placeholder="Select Product"
                        AllowClear="true"
                        AllowFiltering="true"
                        Multiple="true"
                        FilterCaseSensitivity="FilterCaseSensitivity.CaseInsensitive"
                        TextProperty="Name"
                        ValueProperty="Id"
                    @bind-Value=@idProducts
                    Data = @_listProducts />
 <ValidationMessage For="@(() => validProduct)"
                    style="color:red; font-weight:bold;" />

@code{

 [Parameter]
public string validProduct = "";

}

Parent component:-

 <ProductSearch @ref="productSelection" validProduct=@validProduct  ></ProductSearch>

@code {
public string validProduct = "";
private async void OnValidSubmit()
	{
if(model.idProduct == null){
//what should I do here? Actually I want show error message like "Product is Required"
       }
}
}

Parent component model class:-

       [Required(ErrorMessage = "Product is Required")]
        public string? idProduct { get; set; }

How can I do this ?