DxListBox<TData, TValue>.SelectionMode Property

Specifies selection mode.

Assembly : DevExpress.Blazor.v25.2.dll

Declaration

csharp

[Parameter]
public ListBoxSelectionMode SelectionMode { get; set; }

Property Value

Type	Description
ListBoxSelectionMode

A ListBoxSelectionMode enumeration value.

Available values:

Name	Description
Single

Users can only select one List Box item at once.

| | Multiple |

Users can select multiple items in List Box.

| | None |

Users cannot select items in List Box.

Remarks

Single Selection (Default)

Users can select one List Box item at a time.

Use the Value property to get or set the selected item (you can use two-way data binding).
Handle the ValueChanged event to respond to selection changes (if you use one-way data binding).
Razor
StaffData

razor

<DxListBox Data="@Staff.DataSource"
           @bind-Value="@Value"
           TextFieldName="@nameof(Person.Text)"/>

@code{
    Person Value;
}

namespace StaffData {
    public static class Staff {
        private static readonly Lazy<List<Person>> dataSource = new Lazy<List<Person>>(() => {
            var dataSource = new List<Person>() {
                new Person() { Id = 0 , FirstName = "John", LastName = "Heart", Department=Department.Electronics },
                new Person() { Id = 1 , FirstName = "Samantha", LastName = "Bright", Department=Department.Motors },
                new Person() { Id = 2 , FirstName = "Arthur", LastName = "Miller", Department=Department.Software },
                new Person() { Id = 3 , FirstName = "Robert", LastName = "Reagan", Department=Department.Electronics },
                new Person() { Id = 4 , FirstName= "Greta", LastName = "Sims", Department=Department.Motors },
                new Person() { Id = 5 , FirstName = "Brett", LastName = "Wade", Department=Department.Software },
                new Person() { Id = 6 , FirstName = "Sandra", LastName = "Johnson", Department=Department.Electronics },
                new Person() { Id = 7 , FirstName = "Edward", LastName = "Holmes", Department=Department.Motors },
                new Person() { Id = 8 , FirstName = "Barbara", LastName = "Banks", Department=Department.Software },
                new Person() { Id = 9 , FirstName = "Kevin", LastName = "Carter", Department=Department.Electronics }, 
                new Person() { Id = 10, FirstName = "Cynthia", LastName = "Stanwick", Department=Department.Motors },
                new Person() { Id = 11, FirstName = "Sam", LastName = "Hill", Department=Department.Electronics }};
            return dataSource;
        });
        public static List<Person> DataSource { get { return dataSource.Value; } }
    }

    public class Person {
        public int Id { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public Department Department { get; set; }
        public string Text => $"{FirstName} {LastName} ({Department} Dept.)";
        public override bool Equals(object obj) {
            if (obj is Person typedObj) {
                return (this.Id == typedObj.Id) && (this.FirstName == typedObj.FirstName) && (this.LastName == typedObj.LastName)
                && (this.Department == typedObj.Department);
            }
            return base.Equals(obj);
        }
        public override int GetHashCode() {
            return HashCode.Combine(Id, FirstName, LastName);
        }
    }

    public enum Department { Motors, Electronics, Software }
}

Run Demo: List Box - Overview

YouTube video

Multiple Selection

Users can select multiple items.

Set the SelectionMode property to ListBoxSelectionMode.Multiple.
Use the Values property to get or set selected items (you can use two-way data binding).
Handle the ValuesChanged event to respond to selection changes (if you use one-way data binding).
Optional. Use SelectAllAsync() and DeselectAllAsync() methods to select/deselect all available items in code.

The following code enables multiple selection in the List Box, adds checkboxes to items, and shows the Select All checkbox:

Razor
StaffData

razor

@using StaffData

<DxListBox Data="@Staff.DataSource"
           TextFieldName="@nameof(Person.Text)"
           SelectionMode="ListBoxSelectionMode.Multiple"
           ShowCheckboxes="true"
           ShowSelectAllCheckbox="true"
           @bind-Values="@Values">
</DxListBox>

@code {
    IEnumerable<Person> Values { get; set; }
}

csharp

namespace StaffData {
    public static class Staff {
        private static readonly Lazy<List<Person>> dataSource = new Lazy<List<Person>>(() => {
            var dataSource = new List<Person>() {
                new Person() { Id= 0 , FirstName="John", LastName="Heart", Department=Department.Electronics },
                new Person() { Id= 1 , FirstName="Samantha", LastName="Bright", Department=Department.Motors },
                new Person() { Id= 2 , FirstName="Arthur", LastName="Miller", Department=Department.Software },
                new Person() { Id= 3 , FirstName="Robert", LastName="Reagan", Department=Department.Electronics },
                new Person() { Id= 4 , FirstName="Greta", LastName="Sims", Department=Department.Motors },
                new Person() { Id= 5 , FirstName="Brett", LastName="Wade", Department=Department.Software },
                new Person() { Id= 6 , FirstName="Sandra", LastName="Johnson", Department=Department.Electronics },
                new Person() { Id= 7 , FirstName="Edward", LastName="Holmes", Department=Department.Motors },
                new Person() { Id= 8 , FirstName="Barbara", LastName="Banks", Department=Department.Software },
                new Person() { Id= 9 , FirstName="Kevin", LastName="Carter", Department=Department.Electronics },
                new Person() { Id= 10, FirstName="Cynthia", LastName="Stanwick", Department=Department.Motors },
                new Person() { Id= 11, FirstName="Sam", LastName="Hill", Department=Department.Electronics }};
            return dataSource;
        });
        public static List<Person> DataSource { get { return dataSource.Value; } }
    }

    public class Person {
        public int Id { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public Department Department { get; set; }
        public string Text => $"{FirstName} {LastName} ({Department} Dept.)";
        public override bool Equals(object obj) {
            if (obj is Person typedObj) {
                return (this.Id == typedObj.Id) && (this.FirstName == typedObj.FirstName) && (this.LastName == typedObj.LastName)
                && (this.Department == typedObj.Department);
            }
            return base.Equals(obj);
        }
    }

    public enum Department { Motors, Electronics, Software }
}

Run Demo: List Box - Multiple Selection

YouTube video

Disable Selection

Users cannot select items. Use this mode when you want to display a read-only list of items, handle item clicks without selection state, or create a custom selection behavior.

Set the SelectionMode property to ListBoxSelectionMode.None.
The Value and Values properties are ignored.
Optional. You can use the ItemClick event to handle item interaction.
Razor
StaffData

razor

@using BlazorApp.Data

<DxListBox Data="@Staff.DataSource"
           @bind-Values="@Values"
           TextFieldName="@nameof(Person.Text)"
           SelectionMode="ListBoxSelectionMode.None" >
</DxListBox>

@code {
    IEnumerable<Person> Values { get; set; } = Staff.DataSource.Take(1);
}

namespace StaffData {
    public static class Staff {
        private static readonly Lazy<List<Person>> dataSource = new Lazy<List<Person>>(() => {
            var dataSource = new List<Person>() {
                new Person() { Id = 0 , FirstName = "John", LastName = "Heart", Department=Department.Electronics },
                new Person() { Id = 1 , FirstName = "Samantha", LastName = "Bright", Department=Department.Motors },
                new Person() { Id = 2 , FirstName = "Arthur", LastName = "Miller", Department=Department.Software },
                new Person() { Id = 3 , FirstName = "Robert", LastName = "Reagan", Department=Department.Electronics },
                new Person() { Id = 4 , FirstName= "Greta", LastName = "Sims", Department=Department.Motors },
                new Person() { Id = 5 , FirstName = "Brett", LastName = "Wade", Department=Department.Software },
                new Person() { Id = 6 , FirstName = "Sandra", LastName = "Johnson", Department=Department.Electronics },
                new Person() { Id = 7 , FirstName = "Edward", LastName = "Holmes", Department=Department.Motors },
                new Person() { Id = 8 , FirstName = "Barbara", LastName = "Banks", Department=Department.Software },
                new Person() { Id = 9 , FirstName = "Kevin", LastName = "Carter", Department=Department.Electronics }, 
                new Person() { Id = 10, FirstName = "Cynthia", LastName = "Stanwick", Department=Department.Motors },
                new Person() { Id = 11, FirstName = "Sam", LastName = "Hill", Department=Department.Electronics }};
            return dataSource;
        });
        public static List<Person> DataSource { get { return dataSource.Value; } }
    }

    public class Person {
        public int Id { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public Department Department { get; set; }
        public string Text => $"{FirstName} {LastName} ({Department} Dept.)";
        public override bool Equals(object obj) {
            if (obj is Person typedObj) {
                return (this.Id == typedObj.Id) && (this.FirstName == typedObj.FirstName) && (this.LastName == typedObj.LastName)
                && (this.Department == typedObj.Department);
            }
            return base.Equals(obj);
        }
        public override int GetHashCode() {
            return HashCode.Combine(Id, FirstName, LastName);
        }
    }

    public enum Department { Motors, Electronics, Software }
}

Select Items in the UI

Users can select List Box items in the following ways:

Mouse/Touch

In single selection mode, click or tap an item.
In multiple selection mode:
- Hold Ctrl or Option and click items to select them individually.
- Hold Shift to select a range of items.
- Click checkboxes next to items (when ShowCheckboxes is true).
- Click the Select All checkbox (when both ShowSelectAllCheckbox and ShowCheckboxes are true).

Keyboard

Use ↑ and ↓ arrows to focus an item.
Press Space to select/deselect the focused item.
Press Enter to trigger an item click (requires an ItemClick event handler).

Refer to List Box - Keyboard Support for additional information.

Implements

DevExpress.Blazor.IListBox<TData, TValue>.SelectionMode