How to Implement IDataErrorInfo within a WPF Page (A Partial Class)

Question

It's my first experience with WPF. And I'm developing an Inventory Management System. My design model has single Window, in which a frame loads different Pages while clicking on different buttons. While adding a new Inventory into the Database, I want to ensure Data Validation. I choose IDataErrorInfo in this regard. I have to implement the interface but unable to implement just writing as public partial class AddInventoryPage : Page, IDataErrorInfo . This shows error. The signature of the class is as following

public partial class AddInventoryPage : Page

I also tried as under but unable to achieve the functionality. Even I put a breakpoint within IDataErrorInfor part but the control doesn't go there.

namespace IMS
{
    public partial class AddInventoryPage : IDataErrorInfo
    {
    //code here
    }
    public partial class AddInventoryPage : Page
    {
    //code here
    }
}

As My Inventory module is completed except Data Validation, and I'm working on the Sales module; it's not a solution to change my design model. Moreover, I'm not using any Design Pattern like MVVM. It's straight. Looking forward to a solution.

Answer 1

example with a validation against the property 'Name'

public class AddInventoryPage : IDataErrorInfo
{
    public string Name { get; set; }       

    public string Error => null;

    public string this[string columnName]
    {
        get
        {
            switch(columnName)
            {
                case nameof(Name):
                    if (Name == string.Empty) return "Name can not be empty";
            }

            return string.Empty;
        }
    }
}