Table of Contents

Class DropDownBase<T>

Namespace
Radzen
Assembly
Radzen.Blazor.dll

Base class of components that display a list of items.

public class DropDownBase<T> : DataBoundFormComponent<T>, IComponent, IHandleEvent, IHandleAfterRender, IDisposable, IRadzenFormComponent

Type Parameters

T
Inheritance
DropDownBase<T>
Implements
Derived
Inherited Members

Constructors

DropDownBase() 

public DropDownBase()

Fields

list

The list

protected ElementReference? list

Field Value

ElementReference?

The search

protected ElementReference search

Field Value

ElementReference

selectedIndex

The selected index

protected int selectedIndex

Field Value

int

selectedItem

The selected item

protected object selectedItem

Field Value

object

selectedItems

The selected items

protected IList<object> selectedItems

Field Value

IList<object>

Properties

AllowClear

Gets or sets a value indicating whether the user can clear the value. Set to false by default.

[Parameter]
public bool AllowClear { get; set; }

Property Value

bool

true if clearing is allowed; otherwise, false.

AllowFiltering

Gets or sets a value indicating whether filtering is allowed. Set to false by default.

[Parameter]
public virtual bool AllowFiltering { get; set; }

Property Value

bool

true if filtering is allowed; otherwise, false.

AllowSelectAll

Gets or sets a value indicating whether the user can select all values in multiple selection. Set to true by default.

[Parameter]
public bool AllowSelectAll { get; set; }

Property Value

bool

true if select all values is allowed; otherwise, false.

AllowVirtualization

Specifies wether virtualization is enabled. Set to false by default.

[Parameter]
public bool AllowVirtualization { get; set; }

Property Value

bool

Count

Specifies the total number of items in the data source.

[Parameter]
public int Count { get; set; }

Property Value

int

Data

Gets or sets the data.

[Parameter]
public override IEnumerable Data { get; set; }

Property Value

IEnumerable

The data.

DisabledProperty

Gets or sets the disabled property.

[Parameter]
public string DisabledProperty { get; set; }

Property Value

string

The disabled property.

EmptyAriaLabel

Gets or sets the empty value aria label text.

[Parameter]
public string EmptyAriaLabel { get; set; }

Property Value

string

The empty value aria label text.

FilterAsYouType

Gets or sets a value indicating whether filtering is allowed as you type. Set to true by default.

[Parameter]
public virtual bool FilterAsYouType { get; set; }

Property Value

bool

true if filtering is allowed; otherwise, false.

FilterDelay

Gets or sets the filter delay.

[Parameter]
public int FilterDelay { get; set; }

Property Value

int

The filter delay.

HasValue 

public override bool HasValue { get; }

Property Value

bool

HeaderTemplate

Gets or sets the header template.

[Parameter]
public RenderFragment HeaderTemplate { get; set; }

Property Value

RenderFragment

The header template.

Items

Gets the items.

protected virtual IEnumerable<object> Items { get; }

Property Value

IEnumerable<object>

The items.

Multiple

Gets or sets a value indicating whether this DropDownBase<T> is multiple.

[Parameter]
public bool Multiple { get; set; }

Property Value

bool

true if multiple; otherwise, false.

PageSize

Specifies the default page size. Set to 5 by default.

[Parameter]
public int PageSize { get; set; }

Property Value

int

PopupID

Gets the popup identifier.

protected string PopupID { get; }

Property Value

string

The popup identifier.

RemoveChipTitle

Gets or sets the remove chip button title.

[Parameter]
public string RemoveChipTitle { get; set; }

Property Value

string

The remove chip button title.

SearchAriaLabel

Gets or sets the search aria label text.

[Parameter]
public string SearchAriaLabel { get; set; }

Property Value

string

The search aria label text.

SearchID

Gets the search identifier.

public string SearchID { get; }

Property Value

string

The search identifier.

SelectedItem

Gets or sets the selected item.

[Parameter]
public object SelectedItem { get; set; }

Property Value

object

The selected item.

SelectedItemChanged

Gets or sets the selected item changed.

[Parameter]
public EventCallback<object> SelectedItemChanged { get; set; }

Property Value

EventCallback<object>

The selected item changed.

Separator

Gets or sets the item separator for Multiple dropdown.

[Parameter]
public string Separator { get; set; }

Property Value

string

Item separator

Template

Gets or sets the template.

[Parameter]
public RenderFragment<dynamic> Template { get; set; }

Property Value

RenderFragment<dynamic>

The template.

ValueProperty

Gets or sets the value property.

[Parameter]
public string ValueProperty { get; set; }

Property Value

string

The value property.

View

Gets the view.

protected override IEnumerable View { get; }

Property Value

IEnumerable

The view.

VirtualizationOverscanCount

Gets or sets a value that determines how many additional items will be rendered before and after the visible region. This help to reduce the frequency of rendering during scrolling. However, higher values mean that more elements will be present in the page.

[Parameter]
public int VirtualizationOverscanCount { get; set; }

Property Value

int

Virtualize

The Virtualize instance.

public Virtualize<object> Virtualize { get; }

Property Value

Virtualize<object>

Methods

ClearAll()

Clears all.

protected Task ClearAll()

Returns

Task

Dispose() 

public override void Dispose()

GetItemOrValueFromProperty(object, string)

Gets the item or value from property.

public object GetItemOrValueFromProperty(object item, string property)

Parameters

item object

The item.

property string

The property.

Returns

object

System.Object.

GetValue() 

public override object GetValue()

Returns

object

HandleKeyPress(KeyboardEventArgs, bool, bool?)

Handles the key press.

protected virtual Task HandleKeyPress(KeyboardEventArgs args, bool isFilter = false, bool? shouldSelectOnChange = null)

Parameters

args KeyboardEventArgs

The KeyboardEventArgs instance containing the event data.

isFilter bool

if set to true [is filter].

shouldSelectOnChange bool?

Should select item on item change with keyboard.

Returns

Task

OnAfterRenderAsync(bool)

Called when [after render asynchronous].

protected override Task OnAfterRenderAsync(bool firstRender)

Parameters

firstRender bool

if set to true [first render].

Returns

Task

Task.

OnChange(ChangeEventArgs)

Handles the Change event.

protected void OnChange(ChangeEventArgs args)

Parameters

args ChangeEventArgs

The ChangeEventArgs instance containing the event data.

OnDataChanged() 

protected override Task OnDataChanged()

Returns

Task

OnFilter(ChangeEventArgs)

Handles the Filter event.

protected virtual Task OnFilter(ChangeEventArgs args)

Parameters

args ChangeEventArgs

The ChangeEventArgs instance containing the event data.

Returns

Task

OnFilterKeyPress(KeyboardEventArgs)

Handles the FilterKeyPress event.

protected virtual Task OnFilterKeyPress(KeyboardEventArgs args)

Parameters

args KeyboardEventArgs

The KeyboardEventArgs instance containing the event data.

Returns

Task

OnInitialized() 

protected override void OnInitialized()

OnKeyPress(KeyboardEventArgs, bool?)

Handles the KeyPress event.

protected virtual Task OnKeyPress(KeyboardEventArgs args, bool? shouldSelectOnChange = null)

Parameters

args KeyboardEventArgs

The KeyboardEventArgs instance containing the event data.

shouldSelectOnChange bool?

Should select item on item change with keyboard.

Returns

Task

OnParametersSet() 

protected override void OnParametersSet()

OnParametersSetAsync()

Called when [parameters set asynchronous].

protected override Task OnParametersSetAsync()

Returns

Task

Task.

OnSelectItem(object, bool)

Called when [select item].

protected virtual Task OnSelectItem(object item, bool isFromKey = false)

Parameters

item object

The item.

isFromKey bool

if set to true [is from key].

Returns

Task

OpenPopup(string, bool, bool)

Opens the popup.

protected virtual Task OpenPopup(string key = "ArrowDown", bool isFilter = false, bool isFromClick = false)

Parameters

key string

The key.

isFilter bool

if set to true [is filter].

isFromClick bool

if set to true [is from click].

Returns

Task

OpenPopupScript()

Opens the popup script.

protected string OpenPopupScript()

Returns

string

System.String.

OpenPopupScriptFromParent()

Opens the popup script from parent.

protected string OpenPopupScriptFromParent()

Returns

string

System.String.

Reset()

Resets this instance.

public void Reset()

SelectAll()

Selects all.

protected virtual Task SelectAll()

Returns

Task

SelectItem(object, bool)

Selects the item.

public Task SelectItem(object item, bool raiseChange = true)

Parameters

item object

The item.

raiseChange bool

if set to true [raise change].

Returns

Task

SelectItemFromValue(object)

Selects the item from value.

protected virtual void SelectItemFromValue(object value)

Parameters

value object

The value.

SetParametersAsync(ParameterView)

Set parameters as an asynchronous operation.

public override Task SetParametersAsync(ParameterView parameters)

Parameters

parameters ParameterView

The parameters.

Returns

Task

A Task representing the asynchronous operation.