Lookup Editors

• Feb 19, 2024
• 15 minutes to read

Data Lookups

The DevExpress WinForms Subscription includes four lookup controls. Lookups are data-bound editors that display data source records in their dropdowns. Users can select one item (record) at a time. Users cannot edit records in the dropdown.

Standard Lookup

LookUpEdit is a text box editor with a dropdown panel that displays data in a simple table layout.

Run Demo: LookUp Edit

Grid-based Lookup

GridLookUpEdit is a lookup editor that embeds the Data Grid within the dropdown. With the Data Grid’s countless visualization and data presentation options, you have total control over the lookup’s UI/UX.

Run Demo: Grid LookUp

Lookup with Integrated Search

SearchLookUpEdit is a grid-based lookup with an embedded Find Panel. Unlike the GridLookUpEdit, this editor supports Instant Feedback mode, but does not allow users to enter values in the text box.

Run Demo: LookUp with Search

TreeList-based Lookup

TreeListLookUpEdit is a lookup editor that embeds the Tree List control within the dropdown. Users can select values form hierarchical lists.

Run Demo: TreeList LookUp

Feature Matrix

	Lookup	Grid Lookup	TreeList Lookup	Search Lookup
In-Place Mode (use within data-aware controls)
Resizable Dropdown Window
Multiple Columns
Unbound Columns
Show/Hide Horizontal and Vertical Lines
Insert New Records/Values
Auto-Complete
Case Sensitive Search
Sorting
Display Data in Table Layout
Auto-Suggest Mode
Data Aggregation (Summaries)
Arrange Columns into Bands
Row Auto Height
Grouping
Server Mode (Optimized Data Loading)
Instant Feedback UI
Auto-Filter Row
Find Panel
Display Records as Tiles (Table, List, Kanban Board)
Hierarchical Data Structures
Multiple Item Selection

Note

Use the PopupContainerEdit control if you need functionality that is not supported by lookup editors. This control allows you to display any controls within its popup window.

How to Use a PopupContainerEdit to Create an Editable Grid-based Lookup

Bind to Data

Lookups are data-bound controls. Use the following properties to bind a lookup editor to a data source:

• DataSource – Specifies the source of records.
• DisplayMember – The data source field, whose values are visible to users. A value from this field is displayed in the lookup’s text box when a user selects a record.
• ValueMember – The data source field with unique/key values. A value from this data field is assigned to the lookup’s EditValue property when a user selects a record.

Important

When a lookup editor is used to edit cell values in the Data Grid, the type of the ValueMember field must match the type of the field assigned to the grid’s lookup column (GridColumn.FieldName). Enable the lookup’s ThrowExceptionOnInvalidLookUpEditValueType option to detect data type issues.

Use the lookup’s smart tag menu to bind it to data.

The following example shows how to bind a lookup editor to data created at runtime:

C#

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;

public partial class Form1 : DevExpress.XtraEditors.XtraForm {
    public Form1() {
        InitializeComponent();
        // Binds the lookup to data.
        lookUpEdit1.Properties.DataSource = Employee.GetSampleData();
        // Sets the lookup's data fields.
        lookUpEdit1.Properties.DisplayMember = "FullName";
        lookUpEdit1.Properties.ValueMember = "ID";
        // Sets the lookup's value. Selects the first record.
        lookUpEdit1.EditValue = 0;
    }
}

public class Employee {
    public Employee(int iD, string firstName, string lastName) {
        ID = iD;
        FirstName = firstName;
        LastName = lastName;
    }
    public static List<Employee> GetSampleData() {
        return new List<Employee>() {
            new Employee(0, "Bart", "Arnaz"),
            new Employee(1, "Leah", "Simpson"),
            new Employee(2, "Arnold", "Schwartz"),
            new Employee(3, "William", "Zimmer"),
            new Employee(4, "Samantha", "Piper")
        };
    }
    // The 'ID' field must contain unique values.
    public int ID { get; private set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    [Display(Order = -1)]
    public string FullName {
        get {
            return string.Format("{0} {1}", FirstName, LastName);
        }
    }
}

VB.NET

Imports System
Imports System.Collections.Generic
Imports System.ComponentModel.DataAnnotations

Partial Public Class Form1
    Inherits DevExpress.XtraEditors.XtraForm

    Public Sub New()
        InitializeComponent()
        ' Binds the lookup to data.
        lookUpEdit1.Properties.DataSource = Employee.GetSampleData()
        ' Sets the lookup's data fields.
        lookUpEdit1.Properties.DisplayMember = "FullName"
        lookUpEdit1.Properties.ValueMember = "ID"
        ' Sets the lookup's value.
        lookUpEdit1.EditValue = 0
    End Sub
End Class

Public Class Employee
    Public Sub New(ByVal iD As Integer, ByVal firstName As String, ByVal lastName As String)
        Me.ID = iD
        Me.FirstName = firstName
        Me.LastName = lastName
    End Sub
    Public Shared Function GetSampleData() As List(Of Employee)
        Return New List(Of Employee)() From {
            New Employee(0, "Bart", "Arnaz"),
            New Employee(1, "Leah", "Simpson"),
            New Employee(2, "Arnold", "Schwartz"),
            New Employee(3, "William", "Zimmer"),
            New Employee(4, "Samantha", "Piper")
        }
    End Function
    ' The 'ID' field must contain unique values.
    Private privateID As Integer
    Public Property ID() As Integer
        Get
            Return privateID
        End Get
        Private Set(ByVal value As Integer)
            privateID = value
        End Set
    End Property
    Public Property FirstName() As String
    Public Property LastName() As String
    <Display(Order := -1)>
    Public ReadOnly Property FullName() As String
        Get
            Return String.Format("{0} {1}", FirstName, LastName)
        End Get
    End Property
End Class

The image below shows the result.

See the following articles for more information:

• LookUp Standard Binding (Simple Data Types)
• LookUp Advanced Binding (Business Objects)
• How to Bind LookUp to a Dictionary

Tip

How to create a LookUp and use it in the Data Grid

Allow Users to Enter New Values

Set the lookup’s TextEditStyle property to Standard to allow users to type in the text box. Handle the ProcessNewValue event to parse entered values and add new records to the lookup’s data source.

C#

using DevExpress.Utils;
using DevExpress.XtraEditors;
using DevExpress.XtraEditors.Controls;
using System.ComponentModel.DataAnnotations;

public Form1() {
    InitializeComponent();
    // Binds the lookup to data.
    lookUpEdit1.Properties.DataSource = Task.GetSampleData();
    // Sets the lookup's data fields.
    lookUpEdit1.Properties.DisplayMember = "Caption";
    lookUpEdit1.Properties.ValueMember = "ID";
    // Sets the lookup's value.
    lookUpEdit1.EditValue = 0;
    // Enables adding new values.
    lookUpEdit1.Properties.TextEditStyle = TextEditStyles.Standard;
    lookUpEdit1.ProcessNewValue += new ProcessNewValueEventHandler(this.lookUpEdit1_ProcessNewValue);
}
private void lookUpEdit1_ProcessNewValue(object sender, ProcessNewValueEventArgs e) {
    if((string)e.DisplayValue == String.Empty) return;
    List<Task> dataSource = (sender as LookUpEdit).Properties.DataSource as List<Task>;
    dataSource.Add(new Task(dataSource.Count) { Caption = (string)e.DisplayValue});
    e.Handled = true;
}

public class Task {
    public Task(int id) {
        ID = id;
        CreateDate = DateTime.Today;
    }
    [Display(Order = -1)]
    public int ID { get; private set; }
    public string Caption { get; set; }
    public DateTime CreateDate { get; set; }
    public static List<Task> GetSampleData() {
        return new List<Task>() {
            new Task(0){Caption = "Research", CreateDate = new DateTime(2022, 10, 15)},
            new Task(1){Caption = "UI Design", CreateDate = new DateTime(2022, 11, 5)},
            new Task(2){Caption = "Environment Setup", CreateDate = new DateTime(2022, 11, 10)},
            new Task(3){Caption = "Sprint 1", CreateDate = new DateTime(2022, 11, 11)},
            new Task(4){Caption = "Sprint 2", CreateDate = new DateTime(2022, 12, 12)},
            new Task(5){Caption = "Sprint 3", CreateDate = new DateTime(2023, 1, 10)},
            new Task(6){Caption = "Testing", CreateDate = new DateTime(2022, 2, 10)}
        };
    }
}

VB.NET

Imports DevExpress.Utils
Imports DevExpress.XtraEditors
Imports DevExpress.XtraEditors.Controls
Imports System.ComponentModel.DataAnnotations

Public Sub New()
    InitializeComponent()
    ' Binds the lookup to data.
    lookUpEdit1.Properties.DataSource = Task.GetSampleData()
    ' Sets the lookup's data fields.
    lookUpEdit1.Properties.DisplayMember = "Caption"
    lookUpEdit1.Properties.ValueMember = "ID"
    ' Sets the lookup's value.
    lookUpEdit1.EditValue = 0
    ' Enables adding new values.
    lookUpEdit1.Properties.TextEditStyle = TextEditStyles.Standard
    AddHandler lookUpEdit1.ProcessNewValue, AddressOf lookUpEdit1_ProcessNewValue
End Sub
Private Sub lookUpEdit1_ProcessNewValue(ByVal sender As Object, ByVal e As ProcessNewValueEventArgs)
    If CStr(e.DisplayValue) = String.Empty Then
        Return
    End If
    Dim dataSource As List(Of Task) = TryCast((TryCast(sender, LookUpEdit)).Properties.DataSource, List(Of Task))
    dataSource.Add(New Task(dataSource.Count) With {.Caption = CStr(e.DisplayValue)})
    e.Handled = True
End Sub

Public Class Task
    Public Sub New(ByVal id As Integer)
        Me.ID = id
        CreateDate = Date.Today
    End Sub
    Private privateID As Integer
    <Display(Order := -1)>
    Public Property ID() As Integer
        Get
            Return privateID
        End Get
        Private Set(ByVal value As Integer)
            privateID = value
        End Set
    End Property
    Public Property Caption() As String
    Public Property CreateDate() As Date

    Public Shared Function GetSampleData() As List(Of Task)
        Return New List(Of Task)() From {
            New Task(0) With { .Caption = "Research", .CreateDate = New DateTime(2022, 10, 15) },
            New Task(1) With { .Caption = "UI Design", .CreateDate = New DateTime(2022, 11, 5) },
            New Task(2) With { .Caption = "Environment Setup", .CreateDate = New DateTime(2022, 11, 10) },
            New Task(3) With { .Caption = "Sprint 1", .CreateDate = New DateTime(2022, 11, 11) },
            New Task(4) With { .Caption = "Sprint 2", .CreateDate = New DateTime(2022, 12, 12) },
            New Task(5) With { .Caption = "Sprint 3", .CreateDate = New DateTime(2023, 1, 10) },
            New Task(6) With { .Caption = "Testing", .CreateDate = New DateTime(2022, 2, 10) }
        }
    End Function
End Class

Note

The LookUpEdit and GridLookUpEdit support ComboBox mode. In this mode, the lookups behave as a standard ComboBox control. Read the following topic for detailed information: ComboBox Mode for LookUp Controls.

Enable Multiple Item Selection

Important

Multiple item selection is available for the WinForms LookUpEdit control. GridLookUpEdit, TreeListLookUpEdit, and SearchLookUpEdit controls do not support this capability.

Set the EditValueType to ValueList or CSVString to allow users to select multiple items in the LookUpEdit. If you specify this property, the LookUpEdit displays the checkbox selector column and OK / Cancel buttons:

The ShowPopupButtons property allows you to hide OK and Cancel buttons.

You can use AddCheckBoxSelectorColumn() and RemoveCheckBoxSelectorColumn() methods to manually add and remove the checkbox selector column.

Specify the EditValue Type

The EditValueType property specifies the type of the value that the EditValue property returns:

ValueList

The EditValue property returns a List<object> object that contains selected items.

The EnableEditValueCollectionEditing property allows you to bind the EditValue property to a read-only property of a collection type (for example, a HashSet<T>).

CSVString

The EditValue property returns a String object that contains DisplayMember property values of selected items separated by the SeparatorChar followed by the space character.

The following example demonstrates how to activate multiple item selection. The example sets the lookup’s EditValue property to a list with IDs to select corresponding products on app startup:

C#

using System.Windows.Forms;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using DevExpress.XtraEditors;
using DevExpress.XtraEditors.Repository;

public partial class Form1 : XtraForm {
    public Form1() {
        InitializeComponent();
        lookUpEdit1.Properties.DataSource = ProductA.GetList();
        lookUpEdit1.Properties.DisplayMember = "Name";
        lookUpEdit1.Properties.ValueMember = "ID";
        lookUpEdit1.Properties.EditValueType = LookUpEditValueType.ValueList;
        lookUpEdit1.EditValue = new List<object>() {0, 1, 4};
    }
}
public class ProductA {
    int id;
    public ProductA(int id) {
        this.id = id;
    }
    [Display(Order = -1)]
    public int ID {
        get { return id; }
    }
    [Display(ShortName = "Bakery & Desserts")]
    public string Name { get; set; }
    [DisplayFormat(DataFormatString = "c2")]
    public double Price { get; set; }
    public static List<ProductA> GetList() {
        return new List<ProductA>() {
            new ProductA(0){ Name = "Butter Cake", Price = 56.99 },
            new ProductA(1){ Name = "Chocolate Pie ", Price = 89.99 },
            new ProductA(2){ Name = "Frozen Cookie Dough", Price = 54.99 },
            new ProductA(3){ Name = "Truffie Cake", Price = 59.99 },
            new ProductA(4){ Name = "Original Apple Pie", Price = 59.99 }
        };
    }
}

VB.NET

Imports System.Windows.Forms
Imports System.Collections.Generic
Imports System.ComponentModel.DataAnnotations
Imports DevExpress.XtraEditors
Imports DevExpress.XtraEditors.Repository

Partial Public Class Form1
    Inherits XtraForm

    Public Sub New()
        InitializeComponent()
        lookUpEdit1.Properties.DataSource = ProductA.GetList()
        lookUpEdit1.Properties.DisplayMember = "Name"
        lookUpEdit1.Properties.ValueMember = "ID"
        lookUpEdit1.Properties.EditValueType = LookUpEditValueType.ValueList
        lookUpEdit1.EditValue = New List(Of Object)() From {0, 1, 4}
    End Sub
End Class
Public Class ProductA
    Private fid As Integer
    Public Sub New(ByVal id As Integer)
        Me.fid = id
    End Sub
    <Display(Order := -1)>
    Public ReadOnly Property ID() As Integer
        Get
            Return fid
        End Get
    End Property
    <Display(ShortName := "Bakery & Desserts")>
    Public Property Name() As String
    <DisplayFormat(DataFormatString := "c2")>
    Public Property Price() As Double
    Public Shared Function GetList() As List(Of ProductA)
        Return New List(Of ProductA)() From {
            New ProductA(0) With {
                .Name = "Butter Cake",
                .Price = 56.99
            },
            New ProductA(1) With {
                .Name = "Chocolate Pie ",
                .Price = 89.99
            },
            New ProductA(2) With {
                .Name = "Frozen Cookie Dough",
                .Price = 54.99
            },
            New ProductA(3) With {
                .Name = "Truffie Cake",
                .Price = 59.99
            },
            New ProductA(4) With {
                .Name = "Original Apple Pie",
                .Price = 59.99
            }
        }
    End Function
End Class

Bind the Selected State to a Property

You can use the CheckBoxSelectorMember property to define the item’s selected state based on the data source object’s property. In this case, the column generated for this property becomes the selector column:

In this mode, the LookUpEdit updates the specified data source field when a user selects/unselects an item. As a result, the Cancel button is hidden.

The LookUpEdit does not initially populate its EditValue when you specify the CheckBoxSelectorMember property. Specify the EditValue property to display selected items in the edit box.

The following example demonstrates how to bind selection to the “Selected” field (with Boolean values):

C#

public partial class Form1 : XtraForm {
    public Form1() {
        InitializeComponent();
        lookUpEdit2.Properties.DataSource = ProductB.GetList();
        lookUpEdit2.Properties.DisplayMember = "Name";
        lookUpEdit2.Properties.ValueMember = "ID";
        lookUpEdit2.Properties.CheckBoxSelectorMember = "Selected";
        lookUpEdit2.Properties.EditValueType = LookUpEditValueType.ValueList;
        lookUpEdit2.EditValue = new List<object>() {0, 1};
    }
}
public class ProductB {
    int id;
    public ProductB(int id) {
        this.id = id;
    }
    [Display(Order = -1)]
    public int ID {
        get { return id; }
    }
    [Display(ShortName = "Bakery & Desserts")]
    public string Name { get; set; }
    [DisplayFormat(DataFormatString = "c2")]
    public double Price { get; set; }
    public int InStock { get; set; }
    [Display(ShortName = "Add to Order")]
    public bool Selected { get; set; }
    public static List<ProductB> GetProductList() {
        return new List<ProductB>() {
            new ProductB(0){ Name = "Butter Cake", Price = 56.99, InStock = 50 },
            new ProductB(1){ Name = "Chocolate Pie ", Price = 89.99, InStock = 32 },
            new ProductB(2){ Name = "Frozen Cookie Dough", Price = 54.99, InStock = 0 },
            new ProductB(3){ Name = "Truffie Cake", Price = 59.99, InStock = 42 },
            new ProductB(4){ Name = "Original Apple Pie", Price = 59.99, InStock = 0}
        };
    }
}

VB.NET

Partial Public Class Form1
    Inherits XtraForm

    Public Sub New()
        InitializeComponent()
        lookUpEdit2.Properties.DataSource = ProductB.GetList()
        lookUpEdit2.Properties.DisplayMember = "Name"
        lookUpEdit2.Properties.ValueMember = "ID"
        lookUpEdit2.Properties.CheckBoxSelectorMember = "Selected"
        lookUpEdit2.Properties.EditValueType = LookUpEditValueType.ValueList
        lookUpEdit2.EditValue = New List(Of Object)() From {0, 1}
    End Sub
End Class
Public Class ProductB
    Private fid As Integer
    Public Sub New(ByVal id As Integer)
        Me.fid = id
    End Sub
    <Display(Order := -1)>
    Public ReadOnly Property ID() As Integer
        Get
            Return fid
        End Get
    End Property
    <Display(ShortName := "Bakery & Desserts")>
    Public Property Name() As String
    <DisplayFormat(DataFormatString := "c2")>
    Public Property Price() As Double
    Public Property InStock() As Integer
    <Display(ShortName := "Add to Order")>
    Public Property Selected() As Boolean
    Public Shared Function GetProductList() As List(Of ProductB)
        Return New List(Of ProductB)() From {
            New ProductB(0) With {
                .Name = "Butter Cake",
                .Price = 56.99,
                .InStock = 50
            },
            New ProductB(1) With {
                .Name = "Chocolate Pie ",
                .Price = 89.99,
                .InStock = 32
            },
            New ProductB(2) With {
                .Name = "Frozen Cookie Dough",
                .Price = 54.99,
                .InStock = 0
            },
            New ProductB(3) With {
                .Name = "Truffie Cake",
                .Price = 59.99,
                .InStock = 42
            },
            New ProductB(4) With {
                .Name = "Original Apple Pie",
                .Price = 59.99,
                .InStock = 0
            }
        }
    End Function
End Class

Handle the QueryCheckBoxSelectorMemberIsSelected and SetCheckBoxSelectorMemberValue events to convert field values if the specified field is not of the Boolean type.

Control User Behavior

The LookUpEdit raises the following events when a user selects items in the popup:

Method	Description
SelectionChanging	Occurs before a user selects an item in the editor’s popup.
SelectionChanged	Occurs after a user selects an item in the editor’s popup.

Handle the SelectionChanging event and set the e.Cancel parameter to true to cancel item selection:

C#

using DevExpress.XtraEditors.Controls;

public partial class Form1 : XtraForm {
    List<ProductB> products;
    public Form1() {
        InitializeComponent();
        //...
        lookUpEdit1.Properties.SelectionChanging += Properties_SelectionChanging;
    }
    private void Properties_SelectionChanging(object sender, PopupSelectionChangingEventArgs e) {
        e.Cancel = products[e.RecordIndex].InStock == 0;
    }
}

VB.NET

Imports DevExpress.XtraEditors.Controls

Partial Public Class Form1
    Inherits XtraForm

    Private products As List(Of ProductB)
    Public Sub New()
        InitializeComponent()
        '...
        AddHandler lookUpEdit1.Properties.SelectionChanging, AddressOf Properties_SelectionChanging
    End Sub
    Private Sub Properties_SelectionChanging(ByVal sender As Object, ByVal e As PopupSelectionChangingEventArgs)
        e.Cancel = products(e.RecordIndex).InStock = 0
    End Sub
End Class

If the editor works in AutoSearch or AutoSuggest mode, users can type text in the edit box to search for items:

AutoSearch Mode

The LookUpEdit always displays selected items regardless of the search string.

AutoSuggest Mode

The LookUpEdit‘s data source should always include selected items. Add these items to the suggestion collection in the AutoSuggest event handler to support the multiple items selection.

If the edit box contains selected items, users can edit only the last item.

Cascading Lookups

Lookups can filter their values based on the currently selected values of other lookups. See the following examples for detailed information:

• How to Implement Standalone Cascading Lookups
• How to Implement Cascading Lookups within Data Grid Control (In-Place Mode)

Unbound Columns

Lookups can display columns that are not bound to data source fields.

• LookUpEdit – Handle the RepositoryItemLookUpEdit.GetNotInListValue event.

• GridLookUpEdit, SearchLookUpEdit – Use the Grid Unbound Columns feature.

• TreeListLookUpEdit – Use the TreeList Unbound Columns feature.

AutoSuggest and AutoSearch

A lookup can filter its records or suggest matching values as a user types.

Read the corresponding sections in the LookUpEdit topic for detailed information and examples.

Custom Filter Expression

Handle the LookUpEdit’s PopupFilter event to specify a custom filter expression.

C#

using DevExpress.Data.Filtering;
using DevExpress.XtraEditors.Controls;

private void LookUpEdit1_PopupFilter(object sender, PopupFilterEventArgs e)
{
    e.Criteria = CriteriaOperator.Parse(string.Format("DeliveryDate < '{0}'", DateTime.Today));
}

VB.NET

Imports DevExpress.Data.Filtering
Imports DevExpress.XtraEditors.Controls

Private Sub LookUpEdit1_PopupFilter(ByVal sender As Object, ByVal e As PopupFilterEventArgs)
    e.Criteria = CriteriaOperator.Parse("ShipCountry == 'Brazil'")
End Sub

Examples

• WinForms LookupEdit - Standard Binding (Simple Data Types)
• How to filter a Lookup column based on the value of another Lookup column in a Grid Control
• WinForms Lookup Editors - Combobox mode
• Create cascading lookup editors
• How to select multiple items in the WinForms Grid Lookup
• WinForms Data Grid - How to create an editable GridLookUpEdit with PopupContainerEdit
• Display custom text if the lookup’s value is not found in the drop-down list
• WinForms Lookup - Custom draw drop-down rows, cells, and column headers
• WinForms Lookup - Add an empty item to the drop-down list

See Also

• Lookup Editors and Main Settings
• Cascading Lookups
• How to create a LookUp and use it in the Data Grid
• How to Use a PopupContainerEdit to Emulate an Editable Grid-based Lookup