CheckBoxList

in namespace DotVVM.BusinessPack.Controls

Renders a control that renders a list of check boxes for a collection and allows the user to select some of them.

Usage & Scenarios

Renders a list of CheckBox controls and lets the user to select multiple values. The values are stored in a collection bound to the SelectedValues property of the control.

Sample 1: Basic Usage

The DataSource property specifies a collection of strings. For each item in the collection, a checkbox will be created.

The SelectedValues property is bound to a collection which contains all values of checkboxes that are checked. The data-binding works in both ways, so you can either read, or modify the collection in the viewmodel and the checkbox states will be synchronized to reflect changes made to the collection.

page.dothtml
ViewModel.cs

<bp:CheckBoxList DataSource="{value: Countries}"
                 SelectedValues="{value: SelectedCountries}" />

using System.Collections.Generic;
using DotVVM.Framework.ViewModel;

namespace DotvvmWeb.Views.Docs.Controls.businesspack.CheckBoxList.sample1
{
    public class ViewModel : DotvvmViewModelBase
    {
        public List<string> Countries { get; set; } = new List<string> {
            "Czech Republic", "Slovakia", "United States"
        };

        public List<string> SelectedCountries { get; set; } = new List<string>();
    }
}

Sample 2: Working with Objects

When the DataSource collection is bound to a collection of objects, you may use the ItemTextBinding to specify, which property of the object in the collection will be displayed as a text of a particular checkbox control.

The SelectedValues will contain the objects from the DataSource collection which are checked.

In order to allow the control to uniquely identify these objects, you need to use the ItemKeyBinding property to define a property which can work as a key. The key must be unique for all items in the collection, otherwise the control will not work properly.

<bp:CheckBoxList DataSource="{value: Countries}"
                 SelectedValues="{value: SelectedCountries}"
                 ItemTextBinding="{value: Name}"
                 ItemKeyBinding="{value: Id}" />

using System.Collections.Generic;
using DotVVM.Framework.ViewModel;

namespace DotvvmWeb.Views.Docs.Controls.businesspack.CheckBoxList.sample2
{
    public class ViewModel : DotvvmViewModelBase
    {
        public List<Country> Countries { get; set; } = new List<Country> {
            new Country { Id = 1, Name = "Czech Republic" },
            new Country { Id = 2, Name = "Slovakia" },
            new Country { Id = 3, Name = "United States" }
        };

        public List<Country> SelectedCountries { get; set; } = new List<Country>();
    }
}

using System.Collections.Generic;

namespace DotvvmWeb.Views.Docs.Controls.businesspack.CheckBoxList.sample2
{
    public class Country
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public List<string> Cities { get; set; } = new List<string>();
        public bool IsEnabled { get; set; } = true;
        public bool IsChecked { get; set; }
    }
}

Sample 3: Working with Objects 2

To make the SelectedValues property contain only some values from the DataSource objects (like the Id property of the object), you may use the ItemValueBinding property.

The SelectedValues will then contain only the values of the properties specified in the ItemValueBinding. Provided the values of the properties used as a value are unique, you don't need to specify the ItemKeyBinding property.

The ItemKeyBinding property is required only when the control cannot compare the objects in the DataSource collection with the objects in the SelectedValues. If the ItemValueBinding is set and makes the SelectedValues collection use primitive types that can be compared, the ItemKeyBinding property is not needed. Similarly, if the DataSource collection contains only primitive values (string, int etc.), the ItemKeyBinding property is not necessary.

<bp:CheckBoxList DataSource="{value: Countries}"
                 SelectedValues="{value: SelectedCountryIds}"
                 ItemValueBinding="{value: Id}"
                 ItemTextBinding="{value: Name}"/>

using System.Collections.Generic;
using DotVVM.Framework.ViewModel;

namespace DotvvmWeb.Views.Docs.Controls.businesspack.CheckBoxList.sample3
{
    public class ViewModel : DotvvmViewModelBase
    {
        public List<Country> Countries { get; set; } = new List<Country> {
            new Country { Id = 1, Name = "Czech Republic" },
            new Country { Id = 2, Name = "Slovakia" },
            new Country { Id = 3, Name = "United States" }
        };

        public List<int> SelectedCountryIds { get; set; } = new List<int>();
    }
}

using System.Collections.Generic;

namespace DotvvmWeb.Views.Docs.Controls.businesspack.CheckBoxList.sample3
{
    public class Country
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public List<string> Cities { get; set; } = new List<string>();
        public bool IsEnabled { get; set; } = true;
        public bool IsChecked { get; set; }
    }
}

Sample 4: Changed Event

The Changed event is triggered whenever the selection changes.

page.dothtml
ViewModel.cs

<bp:CheckBoxList DataSource="{value: Countries}"
                 SelectedValues="{value: SelectedCountries}"
                 Changed="{command: SelectionChanged()}" />

<p>You've selected {{value: SelectedCountriesCount}} countries.</p>

using System.Collections.Generic;
using DotVVM.Framework.ViewModel;

namespace DotvvmWeb.Views.Docs.Controls.businesspack.CheckBoxList.sample4
{
    public class ViewModel : DotvvmViewModelBase
    {
        public int SelectedCountriesCount { get; set; }

        public List<string> Countries { get; set; } = new List<string> {
            "Czech Republic", "Slovakia", "United States"
        };

        public List<string> SelectedCountries { get; set; } = new List<string>();

        public void SelectionChanged()
        {
            SelectedCountriesCount = SelectedCountries.Count;
        }
    }
}

Sample 5: Disabling CheckBoxes

If you need to disable some of the checkboxes, you can use the ItemEnabledBinding to determine which checkboxes will be enabled and which will not. By default, all checkboxes are enabled and can be checked or unchecked freely.

The Enabled property on the control takes the precedence before the ItemEnabledBinding.

<bp:CheckBoxList DataSource="{value: Countries}"
                 SelectedValues="{value: SelectedCountries}"
                 ItemKeyBinding="{value: Id}"
                 ItemTextBinding="{value: Name}"
                 ItemEnabledBinding="{value: IsEnabled}" />

<br />
<bp:CheckBox Checked="{value: Countries[2].IsEnabled}"
             Text="Enable United States" />

using System.Collections.Generic;
using DotVVM.Framework.ViewModel;

namespace DotvvmWeb.Views.Docs.Controls.businesspack.CheckBoxList.sample5
{
    public class ViewModel : DotvvmViewModelBase
    {

        public List<Country> Countries { get; set; } = new List<Country> {
            new Country { Id = 1, Name = "Czech Republic" },
            new Country { Id = 2, Name = "Slovakia" },
            new Country { Id = 3, Name = "United States", IsEnabled = false }
        };

        public List<Country> SelectedCountries { get; set; } = new List<Country>();
    }
}

using System.Collections.Generic;

namespace DotvvmWeb.Views.Docs.Controls.businesspack.CheckBoxList.sample5
{
    public class Country
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public List<string> Cities { get; set; } = new List<string>();
        public bool IsEnabled { get; set; } = true;
        public bool IsChecked { get; set; }
    }
}

Sample 6: In-place Checked Property

If you do not need to have a second collection with the items that are checked, you can make the control to store the state of the individual items in the items of the DataSource collection.

Let's assume that the DataSource collection items have the IsChecked property. We can have this property set to true or false based on the checkbox state, using the ItemCheckedBinding property.

<bp:CheckBoxList DataSource="{value: Countries}"
                 ItemCheckedBinding="{value: IsChecked}"
                 ItemTextBinding="{value: Name}"
                 ItemKeyBinding="{value: Id}" />

using System.Collections.Generic;
using DotVVM.Framework.ViewModel;

namespace DotvvmWeb.Views.Docs.Controls.businesspack.CheckBoxList.sample6
{
    public class ViewModel : DotvvmViewModelBase
    {
        public List<Country> Countries { get; set; } = new List<Country> {
            new Country { Id = 1, Name = "Czech Republic", IsChecked = true },
            new Country { Id = 2, Name = "Slovakia" },
            new Country { Id = 3, Name = "United States" }
        };
    }
}

using System.Collections.Generic;

namespace DotvvmWeb.Views.Docs.Controls.businesspack.CheckBoxList.sample6
{
    public class Country
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public List<string> Cities { get; set; } = new List<string>();
        public bool IsEnabled { get; set; } = true;
        public bool IsChecked { get; set; }
    }
}

Sample 7: Templates

To display custom content in the control, you can use the ItemTemplate property to declare a custom template for the data source items.

You can also use the EmptyDataTemplate when you want to display contents when the DataSource is empty.

<bp:CheckBoxList DataSource="{value: Countries}"
                 ItemCheckedBinding="{value: IsChecked}"
                 ItemTextBinding="{value: Name}"
                 ItemKeyBinding="{value: Id}">
    <ItemTemplate>
        <span>{{value: Id}}. {{value: Name}}</span>
    </ItemTemplate>
</bp:CheckBoxList>

<br />

<bp:CheckBoxList DataSource="{value: SelectedCountries}"
                 ItemCheckedBinding="{value: IsChecked}"
                 ItemTextBinding="{value: Name}"
                 ItemKeyBinding="{value: Id}">
    <EmptyDataTemplate>
        You must fill the DataSource before you can select countries.
    </EmptyDataTemplate>
</bp:CheckBoxList>

using System.Collections.Generic;
using DotVVM.Framework.ViewModel;

namespace DotvvmWeb.Views.Docs.Controls.businesspack.CheckBoxList.sample7
{
    public class ViewModel : DotvvmViewModelBase
    {
        public List<Country> Countries { get; set; } = new List<Country> {
            new Country { Id = 1, Name = "Czech Republic", IsChecked = true },
            new Country { Id = 2, Name = "Slovakia" },
            new Country { Id = 3, Name = "United States" }
        };

        public List<Country> SelectedCountries { get; set; } = new List<Country>();
    }
}

using System.Collections.Generic;

namespace DotvvmWeb.Views.Docs.Controls.businesspack.CheckBoxList.sample7
{
    public class Country
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public List<string> Cities { get; set; } = new List<string>();
        public bool IsEnabled { get; set; } = true;
        public bool IsChecked { get; set; }
    }
}

Show all inherited properties

Properties

Name	Type	Description	Notes	Default Value
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. The DataContext is null in client-side templates.	attribute inner element static value bindable default	null
DataSource	IEnumerable	Gets or sets the data source containing data for this control.	attribute inner element static value bindable default	null
EmptyDataTemplate	ITemplate	Gets or sets the template displayed when the data source is empty.	attribute inner element static value bindable default	null
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 control client ID within its naming container.	attribute inner element static value bindable default	null
IncludeInPage	Boolean	Gets or sets whether the control is included in the DOM of the page.	attribute inner element static value bindable default	True
InnerText	String	Gets or sets the inner text of the HTML element. Note that this property can only be used on HtmlGenericControl directly and when the control does not have any children.	attribute inner element static value bindable default	null
ItemCheckedBinding	IValueBinding<Boolean?>	Gets or sets the binding indicating whether a particular item is checked.	attribute inner element static value bindable default	null
ItemEnabledBinding	IValueBinding<Boolean?>	Gets or sets the binding indicating whether a data item can be checked.	attribute inner element static value bindable default	null
ItemKeyBinding	IValueBinding	Gets or sets the binding which retrieves the unique key of a data item.	attribute inner element static value bindable default	null
ItemTemplate	ITemplate	Gets or sets the template used to render each item in the data source.	attribute inner element static value bindable default	null
ItemTextBinding	IValueBinding<String>	Gets or sets the binding which retrieves text from a data item. It retrieves the whole item by default.	attribute inner element static value bindable default	null
ItemValueBinding	IValueBinding	Gets or sets the binding which retrieves a value from a checked data item. It retrieves the whole item by default.	attribute inner element static value bindable default	null
SelectedValues	IEnumerable	Gets or sets a collection of values of all items that are checked.	attribute inner element static value bindable default	null
Visible	Boolean	Gets or sets whether the control is visible. When set to false, `style="display: none"` will be added to this control.	attribute inner element static value bindable default	True

Events

	Name	Type	Description
	Changed	ICommandBinding	Gets or sets the command triggered when an item is (un)checked.

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