Combobox Mode - Allow Entering New Values

using DevExpress.XtraEditors;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Lookup_ComboboxMode {
    public partial class Form1 : Form {
        public Form1() {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e) {
            initLookupEdit();
            initGridLookupEdit();
        }


        void initLookupEdit() {
            lookUpEdit1.EditValueChanged += LookUpEdit1_EditValueChanged; ;
            lookUpEdit1.Properties.NullText = "(select or type value)";

            string[] colors = new string[] {
                "Yellow", "Red", "Green", "Black", "White"
            };

            lookUpEdit1.Properties.DataSource = colors;
            lookUpEdit1.Properties.TextEditStyle = DevExpress.XtraEditors.Controls.TextEditStyles.Standard;
            lookUpEdit1.Properties.AcceptEditorTextAsNewValue = DevExpress.Utils.DefaultBoolean.Default; //Default is equivalent to True for LookupEdit control
        }





        void initGridLookupEdit() {
            gridLookUpEdit1.EditValueChanged += LookUpEdit1_EditValueChanged;
            gridLookUpEdit1.Properties.NullText = "(select or type value)";

            List<Product> products = new List<Product> {
                new Product(){ ProductName="Chang" },
                new Product(){ ProductName="Ipoh Coffee" },
                new Product(){ ProductName="Ravioli Angelo" },
                new Product(){ ProductName="Filo Mix" },
                new Product(){ ProductName="Tunnbröd" },
                new Product(){ ProductName="Konbu" },
                new Product(){ ProductName="Boston Crab Meat" }
            };

            gridLookUpEdit1.Properties.DataSource = products;
            gridLookUpEdit1.Properties.TextEditStyle = DevExpress.XtraEditors.Controls.TextEditStyles.Standard;
            gridLookUpEdit1.Properties.AcceptEditorTextAsNewValue = DevExpress.Utils.DefaultBoolean.True;
            gridLookUpEdit1.Properties.ValueMember = "ProductName";
            gridLookUpEdit1.Properties.DisplayMember = gridLookUpEdit1.Properties.ValueMember;
            gridLookUpEdit1.ProcessNewValue += GridLookUpEdit1_ProcessNewValue;
            
        }

        

        Dictionary<LookUpEditBase, LabelControl> labelDictionaryCore;
        Dictionary<LookUpEditBase, LabelControl> labelDictionary {
            get {
                if (labelDictionaryCore == null) {
                    labelDictionaryCore = new Dictionary<LookUpEditBase, LabelControl>();
                    labelDictionaryCore.Add(lookUpEdit1, labelControl1);
                    labelDictionaryCore.Add(gridLookUpEdit1, labelControl2);
                }
                return labelDictionaryCore;
            }
        }

        private void LookUpEdit1_EditValueChanged(object sender, EventArgs e) {
            //Display lookup editor's current value.
            LookUpEditBase lookupEditor = sender as LookUpEditBase;
            if (lookupEditor == null) return;
            LabelControl label = labelDictionary[lookupEditor];
            if (label == null) return;
            if (lookupEditor.EditValue == null)
                label.Text = "Current EditValue: null";
            else
                label.Text = "Current EditValue: " + lookupEditor.EditValue.ToString();
        }

        private void GridLookUpEdit1_ProcessNewValue(object sender, DevExpress.XtraEditors.Controls.ProcessNewValueEventArgs e) {
            //Add new values to GridLookUpEdit control's DataSource.
            GridLookUpEdit gridLookup = sender as GridLookUpEdit;
            if (e.DisplayValue == null) return;
            string newValue = e.DisplayValue.ToString();
            if (newValue == String.Empty) return;
            if (MessageBox.Show(this, "Add '" + newValue + "' to list?", "Confirm", MessageBoxButtons.YesNo) == DialogResult.Yes) {
                List<Product> ds = gridLookup.Properties.DataSource as List<Product>;
                ds.Add(new Product { ProductName = newValue });
                e.Handled = true;
            }
        }
    }

    public class Product {
        public string ProductName { get; set; }
    }


}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Lookup_ComboboxMode {
    static class Program {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main() {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Form1());
        }
    }
}

Imports DevExpress.XtraEditors
Imports System
Imports System.Collections.Generic
Imports System.ComponentModel
Imports System.Data
Imports System.Drawing
Imports System.Linq
Imports System.Text
Imports System.Threading.Tasks
Imports System.Windows.Forms

Namespace Lookup_ComboboxMode
    Partial Public Class Form1
        Inherits Form

        Public Sub New()
            InitializeComponent()
        End Sub

        Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
            initLookupEdit()
            initGridLookupEdit()
        End Sub


        Private Sub initLookupEdit()
            AddHandler lookUpEdit1.EditValueChanged, AddressOf LookUpEdit1_EditValueChanged

            lookUpEdit1.Properties.NullText = "(select or type value)"

            Dim colors() As String = { "Yellow", "Red", "Green", "Black", "White" }

            lookUpEdit1.Properties.DataSource = colors
            lookUpEdit1.Properties.TextEditStyle = DevExpress.XtraEditors.Controls.TextEditStyles.Standard
            lookUpEdit1.Properties.AcceptEditorTextAsNewValue = DevExpress.Utils.DefaultBoolean.Default 'Default is equivalent to True for LookupEdit control
        End Sub





        Private Sub initGridLookupEdit()
            AddHandler gridLookUpEdit1.EditValueChanged, AddressOf LookUpEdit1_EditValueChanged
            gridLookUpEdit1.Properties.NullText = "(select or type value)"

            Dim products As New List(Of Product) From { _
                New Product() With {.ProductName="Chang"}, _
                New Product() With {.ProductName="Ipoh Coffee"}, _
                New Product() With {.ProductName="Ravioli Angelo"}, _
                New Product() With {.ProductName="Filo Mix"}, _
                New Product() With {.ProductName="Tunnbröd"}, _
                New Product() With {.ProductName="Konbu"}, _
                New Product() With {.ProductName="Boston Crab Meat"} _
            }

            gridLookUpEdit1.Properties.DataSource = products
            gridLookUpEdit1.Properties.TextEditStyle = DevExpress.XtraEditors.Controls.TextEditStyles.Standard
            gridLookUpEdit1.Properties.AcceptEditorTextAsNewValue = DevExpress.Utils.DefaultBoolean.True
            gridLookUpEdit1.Properties.ValueMember = "ProductName"
            gridLookUpEdit1.Properties.DisplayMember = gridLookUpEdit1.Properties.ValueMember
            AddHandler gridLookUpEdit1.ProcessNewValue, AddressOf GridLookUpEdit1_ProcessNewValue

        End Sub



        Private labelDictionaryCore As Dictionary(Of LookUpEditBase, LabelControl)
        Private ReadOnly Property labelDictionary() As Dictionary(Of LookUpEditBase, LabelControl)
            Get
                If labelDictionaryCore Is Nothing Then
                    labelDictionaryCore = New Dictionary(Of LookUpEditBase, LabelControl)()
                    labelDictionaryCore.Add(lookUpEdit1, labelControl1)
                    labelDictionaryCore.Add(gridLookUpEdit1, labelControl2)
                End If
                Return labelDictionaryCore
            End Get
        End Property

        Private Sub LookUpEdit1_EditValueChanged(ByVal sender As Object, ByVal e As EventArgs)
            'Display lookup editor's current value.
            Dim lookupEditor As LookUpEditBase = TryCast(sender, LookUpEditBase)
            If lookupEditor Is Nothing Then
                Return
            End If
            Dim label As LabelControl = labelDictionary(lookupEditor)
            If label Is Nothing Then
                Return
            End If
            If lookupEditor.EditValue Is Nothing Then
                label.Text = "Current EditValue: null"
            Else
                label.Text = "Current EditValue: " & lookupEditor.EditValue.ToString()
            End If
        End Sub

        Private Sub GridLookUpEdit1_ProcessNewValue(ByVal sender As Object, ByVal e As DevExpress.XtraEditors.Controls.ProcessNewValueEventArgs)
            'Add new values to GridLookUpEdit control's DataSource.
            Dim gridLookup As GridLookUpEdit = TryCast(sender, GridLookUpEdit)
            If e.DisplayValue Is Nothing Then
                Return
            End If
            Dim newValue As String = e.DisplayValue.ToString()
            If newValue = String.Empty Then
                Return
            End If
            If MessageBox.Show(Me, "Add '" & newValue & "' to list?", "Confirm", MessageBoxButtons.YesNo) = System.Windows.Forms.DialogResult.Yes Then
                Dim ds As List(Of Product) = TryCast(gridLookup.Properties.DataSource, List(Of Product))
                ds.Add(New Product With {.ProductName = newValue})
                e.Handled = True
            End If
        End Sub
    End Class

    Public Class Product
        Public Property ProductName() As String
    End Class


End Namespace

Imports System
Imports System.Collections.Generic
Imports System.Linq
Imports System.Threading.Tasks
Imports System.Windows.Forms

Namespace Lookup_ComboboxMode
    Friend NotInheritable Class Program

        Private Sub New()
        End Sub

        ''' <summary>
        ''' The main entry point for the application.
        ''' </summary>
        <STAThread> _
        Shared Sub Main()
            Application.EnableVisualStyles()
            Application.SetCompatibleTextRenderingDefault(False)
            Application.Run(New Form1())
        End Sub
    End Class
End Namespace