ListBox

in namespace DotVVM.Framework.Controls

Renders the HTML list box.

Usage & Scenarios

Renders the HTML listbox.

Sample 1: Basic ListBox

The ListBox control has property DataSource which expects an IEnumerable. Each object is treated as an item in the listbox.

The SelectedValue property will contain the selected value.

page.dothtml
ViewModel.cs

<dot:ListBox DataSource="{value: Fruits}" SelectedValue="{value: SelectedFruit}"/>

{{value: SelectedFruit}}

namespace DotvvmWeb.Views.Docs.Controls.builtin.ListBox.sample1
{
    public class ViewModel
    {
        public string[] Fruits { get; set; } 
            = { "Apple", "Banana", "Orange" };

        public string SelectedFruit { get; set; }
    }
}

Sample 2: ListBox Size

The ListBox control has the Size property which specifies how many lines will be visible without scrolling.

page.dothtml
ViewModel.cs

<dot:ListBox DataSource="{value: Fruits}" 
              SelectedValue="{value: SelectedFruit}" 
              Size="5" />

{{value: SelectedFruit}}

namespace DotvvmWeb.Views.Docs.Controls.builtin.ListBox.sample2
{
    public class ViewModel
    {
        public string[] Fruits { get; set; } 
            = { "Apple", "Banana", "Orange", "Mandarin", "Pear", "Avocado" };

        public string SelectedFruit { get; set; }
    }
}

Sample 3: ValueMember and DisplayMember

Typically, the DataSource is not a collection of strings, but a collection of some complex objects.

The ValueMember property defines which property of the object will be passed to the SelectedValue property.

The DisplayMember property defines which property of the object will be displayed in the drop-down list.

page.dothtml
ViewModel.cs

<dot:ListBox DataSource="{value: Fruits}" SelectedValue="{value: SelectedFruitId}" 
             ValueMember="Id" DisplayMember="Name" />

{{value: SelectedFruitId}}

namespace DotvvmWeb.Views.Docs.Controls.builtin.ListBox.sample3
{
    public class ViewModel
    {
        public Fruit[] Fruits { get; set; } = 
        {
            new Fruit(0, "Apple"),
            new Fruit(1, "Banana"),
            new Fruit(2, "Orange")
        };

        public int SelectedFruitId { get; set; } = 1;
    }

    public class Fruit
    {
        public int Id { get; set; }

        public string Name { get; set; }

        public Fruit(int id, string name)
        {
            Id = id;
            Name = name;
        }
    }
}

Sample 4: SelectionChanged Event

The ListBox control also has the SelectionChanged event which is fired whenever the selection changes.

page.dothtml
ViewModel.cs

<dot:ListBox DataSource="{value: Fruits}" SelectedValue="{value: SelectedFruit}" 
             SelectionChanged="{command: IsItReallyFruit()}"/>

{{value: Message}}

namespace DotvvmWeb.Views.Docs.Controls.builtin.ListBox.sample4
{
    public class ViewModel
    {
        public string[] Fruits { get; set; } = { "Apple", "Banana", "IceCream", "Orange" };

        public string SelectedFruit { get; set; }

        public string Message { get; set; }

        public void IsItReallyFruit()
        {
            if (SelectedFruit == "IceCream")
            {
                Message = "Ice cream isn't a fruit!";
            }
            else
            {
                Message = "Yes, it's a fruit!";
            }
        }
    }
}

Sample 5: ListBox Game

A simple trivia game - match inventors to inventions.

page.dothtml
ViewModel.cs

<h3>Match inventors and inventions</h3>

<dot:ListBox DataSource="{value: Inventors}" SelectedValue="{value: SelectedInventor}"
       DisplayMember="Name" ValueMember="Id"/>

<dot:ListBox DataSource="{value: Inventions}" SelectedValue="{value: SelectedInvention}" />

<dot:Button Text="Check Answers" Click="{command: CheckAnswer()}" />

<p>Points: {{value: Points}}</p>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using DotVVM.Framework.ViewModel;

namespace DotvvmWeb.Views.Docs.Controls.builtin.ListBox.sample5
{
    public class ViewModel : DotvvmViewModelBase
    {
        public List<Inventor> Inventors { get; set; } = new List<Inventor>()
        {
            new Inventor(0, "Thomas Edison", "Lightbulb"),
            new Inventor(1, "Alexander Graham Bell", "Telephone"),
            new Inventor(2, "Benjamin Franklin", "Electricity"),
            new Inventor(3, "Tim Berners Lee", "HTTP Protocol"),
            new Inventor(4, "Sir John Harrington", "Toilet"),
            new Inventor(5, "Emile Berliner", "Gramophone Record")
        };

        public int? SelectedInventor { get; set; } = null;

        public List<string> Inventions { get; set; }

        public string SelectedInvention { get; set; }

        public int Points { get; set; } = 0;

        public override Task Init()
        {
            // generate random order when the page is loaded the first time
            if (!Context.IsPostBack)
            {
                Inventions = Inventors
                    .OrderBy(i => Guid.NewGuid())
                    .Select(i => i.Invention)
                    .ToList();
            }

            return base.Init();
        }

        public void CheckAnswer()
        {
            var selectedInventor = Inventors.First(i => i.Id == SelectedInventor);
            if (selectedInventor.Invention == SelectedInvention)
            {
                Inventors.Remove(selectedInventor);
                Inventions.Remove(selectedInventor.Invention);

                SelectedInventor = null;
                SelectedInvention = null;

                Points++;
            }
            else
            {
                Points = Points - 2;
            }
        }
    }

    public class Inventor
    {
        public string Name { get; set; }

        public string Invention { get; set; }

        public int Id { get; set; }

        public Inventor()
        {

        }
        public Inventor(int id, string name, string invention)
        {
            Id = id;
            Name = name;
            Invention = invention;
        }
    }
}

Properties

Name	Type	Description	Notes	Default Value
Attributes	Dictionary<String,Object>		attribute inner element static value bindable default	null
ClientIDMode	ClientIDMode	Gets or sets the client ID generation algorithm.	attribute inner element static value bindable default	Static
DataContext	Object	Gets or sets a data context for the control and its children. All value and command bindings are evaluated in context of this value.	attribute inner element static value bindable default	null
DataSource	Object	Gets or sets the source collection or a GridViewDataSet that contains data in the control.	attribute inner element static value bindable default	null
DisplayMember	String	Gets or sets the name of property in the DataSource collection that will be displayed in the control.	attribute inner element static value bindable default
Enabled	Boolean	Gets or sets a value indicating whether the control is enabled and can be modified.	attribute inner element static value bindable default	True
ID	String	Gets or sets the unique control ID.	attribute inner element static value bindable default	null
InnerText	String	Gets or sets the inner text of the HTML element.	attribute inner element static value bindable default	null
SelectedValue	Object	Gets or sets the value of the selected item.	attribute inner element static value bindable default	null
Size	Int32	Gets or sets number of rows visible in this ListBox.	attribute inner element static value bindable default	10
ValueMember	String	Gets or sets the name of property in the DataSource collection that will be passed to the SelectedValue property when the item is selected.	attribute inner element static value bindable default
Visible	Boolean	Gets or sets whether the control is visible.	attribute inner element static value bindable default	True

Events

	Name	Type	Description
	SelectionChanged	Command	Gets or sets the command that will be triggered when the selection is changed.

HTML produced by the control

The control renders the HTML select:

<select data-bind="..." size="4"></select>