using DevExpress.XtraEditors;
using DevExpress.XtraEditors.DXErrorProvider;
using DevExpress.XtraGrid;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Runtime.CompilerServices;
using System.Windows.Forms;

namespace DXApplication19 {
    public partial class Form1 : DevExpress.XtraEditors.XtraForm {
        public Form1() {
            InitializeComponent();

            GridControl gridControl1 = new GridControl();
            Controls.Add(gridControl1);
            gridControl1.Dock = DockStyle.Fill;

            //Create a data source
            BindingList<Customer> list = new BindingList<Customer>();
            list.Add(new Customer("Andrew", "Weber"));
            list.Add(new Customer("", "Kovar")); // An invalid first name
            list.Add(new Customer("Kathy", "")); // An invalid last name

            BindingSource bindingSource1 = new BindingSource(list, "");
            gridControl1.DataSource = bindingSource1;

            // To show data source errors in standalone editors, bind a DXErrorProvider to the data source.
            DXErrorProvider dxErrorProvider1 = new DXErrorProvider(this);
            dxErrorProvider1.DataSource = bindingSource1;

            // Create a TextEdit control and bind it to the First Name field
            TextEdit textEdit1 = new TextEdit();
            textEdit1.DataBindings.Add(new Binding("EditValue", bindingSource1, "FirstName"));

            LabelControl label = new LabelControl();
            label.Padding = new Padding(0, 30, 0, 5);
            label.Text = "TextEdit bound to FirstName field:";

            Controls.Add(label);
            label.Dock = DockStyle.Bottom;

            Controls.Add(textEdit1);
            textEdit1.Dock = DockStyle.Bottom;

        }
    }

    public class Customer: IDataErrorInfo, INotifyPropertyChanged {
        public Customer(string firstName, string lastName) {
            FirstName = firstName;
            LastName = lastName;

        }
        string firstName;
        public string FirstName {
            get {
                return firstName;
            }
            set {
                ValidateValue(value);
                firstName = value;
                OnPropertyChanged();
            }
        }

        string lastName;
        public string LastName {
            get {
                return lastName;
            }
            set {
                ValidateValue(value);
                lastName = value;
                OnPropertyChanged();
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;
        public virtual void OnPropertyChanged([CallerMemberName] String propertyName = "") {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }

        // Stores errors for all properties of the Customer class.
        Dictionary<string, string> PropertyErrors = new Dictionary<string, string>();
        string IDataErrorInfo.this[string propertyName] {
            get {
                string errorText;
                return PropertyErrors.TryGetValue(propertyName, out errorText) ? errorText : null;
            }
        }
        string IDataErrorInfo.Error => string.Empty;

        // Clears or sets errors for the FirstName and LastName fields.
        void ValidateValue(string value, [CallerMemberName] String propertyName="") {
            bool isValid = !string.IsNullOrEmpty(value);
            if (isValid) {
                //Clear a previous error, if any.
                PropertyErrors.Remove(propertyName);
            }
            else {
                //Set an error.
                string errorText = propertyName + " is required";
                PropertyErrors[propertyName] = errorText;
            }
        }

    }
}

Imports System.ComponentModel
Imports System.Runtime.CompilerServices
Imports DevExpress.XtraEditors
Imports DevExpress.XtraEditors.DXErrorProvider
Imports DevExpress.XtraGrid

Partial Public Class Form1
    Public Sub New()
        InitializeComponent()
    End Sub

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Dim gridControl1 As GridControl = New GridControl()
        Controls.Add(gridControl1)
        gridControl1.Dock = DockStyle.Fill

        'Create a data source
        Dim list As BindingList(Of Customer) = New BindingList(Of Customer)()
        list.Add(New Customer("Andrew", "Weber"))
        list.Add(New Customer("", "Kovar")) ' An invalid first name
        list.Add(New Customer("Kathy", "")) ' An invalid last name

        Dim bindingSource1 As BindingSource = New BindingSource(list, "")
        gridControl1.DataSource = bindingSource1

        ' To show data source errors in standalone editors, bind a DXErrorProvider to the data source.
        Dim dxErrorProvider1 As New DXErrorProvider(Me)
        dxErrorProvider1.DataSource = bindingSource1

        ' Create a TextEdit control and bind it to the First Name field
        Dim textEdit1 As TextEdit = New TextEdit()
        textEdit1.DataBindings.Add(New Binding("EditValue", bindingSource1, "FirstName"))

        Dim label As LabelControl = New LabelControl()
        label.Padding = New Padding(0, 30, 0, 5)
        label.Text = "TextEdit bound to FirstName field:"

        Controls.Add(label)
        label.Dock = DockStyle.Bottom

        Controls.Add(textEdit1)
        textEdit1.Dock = DockStyle.Bottom
    End Sub
End Class

Public Class Customer
    Implements IDataErrorInfo, INotifyPropertyChanged
    Public Sub New(ByVal firstName_Renamed As String, ByVal lastName_Renamed As String)
        Me.FirstName = firstName_Renamed
        Me.LastName = lastName_Renamed

    End Sub
    Private firstName_Renamed As String
    Public Property FirstName() As String
        Get
            Return firstName_Renamed
        End Get
        Set
            ValidateValue(Value)
            firstName_Renamed = Value
            OnPropertyChanged()
        End Set
    End Property

    Private lastName_Renamed As String
    Public Property LastName() As String
        Get
            Return lastName_Renamed
        End Get
        Set
            ValidateValue(Value)
            lastName_Renamed = Value
            OnPropertyChanged()
        End Set
    End Property

    Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged
    Public Overridable Sub OnPropertyChanged(<CallerMemberName()> Optional ByVal propertyName As String = Nothing)
        RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(propertyName))
    End Sub

    ' Stores errors for all properties of the Customer class.
    Private PropertyErrors As Dictionary(Of String, String) = New Dictionary(Of String, String)()
    Private ReadOnly Property Item(ByVal propertyName As String) As String Implements IDataErrorInfo.Item
        Get
            Dim errorText As String = ""
            If PropertyErrors.TryGetValue(propertyName, errorText) Then
                Return errorText
            Else
                Return Nothing
            End If
        End Get
    End Property

    Private ReadOnly Property [Error] As String Implements IDataErrorInfo.Error
        Get
            Return ""
        End Get
    End Property

    Private Sub ValidateValue(ByVal value As String, <CallerMemberName> ByVal Optional propertyName As String = Nothing)
        Dim isValid As Boolean = Not String.IsNullOrEmpty(value)
        If isValid Then
            'Clear a previous error, if any.
            PropertyErrors.Remove(propertyName)
        Else
            'Set an error.
            Dim errorText As String = propertyName & " is required"
            PropertyErrors(propertyName) = errorText
        End If
    End Sub
End Class