Class DropDownBase<T>

Base class of components that display a list of items.

Inheritance

object

ComponentBase

RadzenComponent

DataBoundFormComponent<T>

DropDownBase<T>

RadzenDropDownDataGrid<TValue>

RadzenDropDown<TValue>

RadzenListBox<TValue>

Implements

IComponent

IHandleEvent

IHandleAfterRender

IDisposable

IRadzenFormComponent

Inherited Members

DataBoundFormComponent<T>._view

DataBoundFormComponent<T>.GetClassList(string)

DataBoundFormComponent<T>.FocusAsync()

DataBoundFormComponent<T>.OnContextMenu(MouseEventArgs)

DataBoundFormComponent<T>.TabIndex

DataBoundFormComponent<T>.FilterCaseSensitivity

DataBoundFormComponent<T>.FilterOperator

DataBoundFormComponent<T>.Name

DataBoundFormComponent<T>.Placeholder

DataBoundFormComponent<T>.Disabled

DataBoundFormComponent<T>.Change

DataBoundFormComponent<T>.LoadData

DataBoundFormComponent<T>.Form

DataBoundFormComponent<T>.Value

DataBoundFormComponent<T>.ValueChanged

DataBoundFormComponent<T>.IsBound

DataBoundFormComponent<T>.TextProperty

DataBoundFormComponent<T>.Query

DataBoundFormComponent<T>.SearchText

DataBoundFormComponent<T>.SearchTextChanged

DataBoundFormComponent<T>.EditContext

DataBoundFormComponent<T>.FieldIdentifier

DataBoundFormComponent<T>.ValueExpression

DataBoundFormComponent<T>.FormFieldContext

DataBoundFormComponent<T>.CurrentPlaceholder

RadzenComponent.OnMouseEnter()

RadzenComponent.OnMouseLeave()

RadzenComponent.GetCssClass()

RadzenComponent.GetId()

RadzenComponent.GetComponentCssClass()

RadzenComponent.Debounce(Func<Task>, int)

RadzenComponent.RaiseContextMenu(MouseEventArgs)

RadzenComponent.RaiseMouseEnter()

RadzenComponent.AddContextMenu()

RadzenComponent.RaiseMouseLeave()

RadzenComponent.Attributes

RadzenComponent.Element

RadzenComponent.MouseEnter

RadzenComponent.MouseLeave

RadzenComponent.ContextMenu

RadzenComponent.Culture

RadzenComponent.DefaultCulture

RadzenComponent.Style

RadzenComponent.Visible

RadzenComponent.UniqueID

RadzenComponent.JSRuntime

RadzenComponent.IsJSRuntimeAvailable

RadzenComponent.Reference

RadzenComponent.CurrentStyle

ComponentBase.BuildRenderTree(RenderTreeBuilder)

ComponentBase.OnInitializedAsync()

ComponentBase.StateHasChanged()

ComponentBase.ShouldRender()

ComponentBase.OnAfterRender(bool)

ComponentBase.InvokeAsync(Action)

ComponentBase.InvokeAsync(Func<Task>)

ComponentBase.DispatchExceptionAsync(Exception)

object.GetType()

object.MemberwiseClone()

object.ToString()

object.Equals(object)

object.Equals(object, object)

object.ReferenceEquals(object, object)

object.GetHashCode()

Namespace: Radzen

Assembly: Radzen.Blazor.dll

Syntax

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

Type Parameters

Name	Description
T

Constructors

DropDownBase()

Base class of components that display a list of items.

Declaration

public DropDownBase()

Fields

PreserveCollectionOnSelection

Will add/remove selected items from a bound ICollection<T>, instead of replacing it.

Declaration

protected bool PreserveCollectionOnSelection

Field Value

Type	Description
bool

list

The list

Declaration

protected ElementReference? list

Field Value

Type	Description
ElementReference?

search

The search

Declaration

protected ElementReference search

Field Value

Type	Description
ElementReference

selectedIndex

The selected index

Declaration

protected int selectedIndex

Field Value

Type	Description
int

selectedItem

The selected item

Declaration

protected object selectedItem

Field Value

Type	Description
object

selectedItems

The selected items

Declaration

protected ISet<object> selectedItems

Field Value

Type	Description
ISet<object>

Properties

AllowClear

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

Declaration

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

Property Value

Type	Description
bool	true if clearing is allowed; otherwise, false.

AllowFiltering

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

Declaration

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

Property Value

Type	Description
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.

Declaration

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

Property Value

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

AllowVirtualization

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

Declaration

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

Property Value

Type	Description
bool

Count

Specifies the total number of items in the data source.

Declaration

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

Property Value

Type	Description
int

Data

Gets or sets the data.

Declaration

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

Property Value

Type	Description
IEnumerable	The data.

Overrides

DataBoundFormComponent<T>.Data

DisabledProperty

Gets or sets the disabled property.

Declaration

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

Property Value

Type	Description
string	The disabled property.

EmptyAriaLabel

Gets or sets the empty value aria label text.

Declaration

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

Property Value

Type	Description
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.

Declaration

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

Property Value

Type	Description
bool	true if filtering is allowed; otherwise, false.

FilterDelay

Gets or sets the filter delay.

Declaration

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

Property Value

Type	Description
int	The filter delay.

HasValue

Gets a value indicating whether this instance has value.

Declaration

public override bool HasValue { get; }

Property Value

Type	Description
bool	true if this instance has value; otherwise, false.

Overrides

DataBoundFormComponent<T>.HasValue

HeaderTemplate

Gets or sets the header template.

Declaration

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

Property Value

Type	Description
RenderFragment	The header template.

ItemComparer

For lists of objects, an IEqualityComparer to control how selected items are determined

Declaration

[Parameter]
public IEqualityComparer<object> ItemComparer { get; set; }

Property Value

Type	Description
IEqualityComparer<object>

Items

Gets the items.

Declaration

protected virtual IEnumerable<object> Items { get; }

Property Value

Type	Description
IEnumerable<object>	The items.

Multiple

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

Declaration

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

Property Value

Type	Description
bool	true if multiple; otherwise, false.

PageSize

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

Declaration

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

Property Value

Type	Description
int

PopupID

Gets the popup identifier.

Declaration

protected string PopupID { get; }

Property Value

Type	Description
string	The popup identifier.

RemoveChipTitle

Gets or sets the remove chip button title.

Declaration

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

Property Value

Type	Description
string	The remove chip button title.

ResetSelectedIndexOnFilter

Gets or sets a value indicating the selected index should reset to the top item when filtering, resulting in a down arrow action will start moving from the top.

Declaration

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

Property Value

Type	Description
bool	true to reset selected index to -1 when filtering; otherwise, false.

SearchAriaLabel

Gets or sets the search aria label text.

Declaration

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

Property Value

Type	Description
string	The search aria label text.

SearchID

Gets the search identifier.

Declaration

public string SearchID { get; }

Property Value

Type	Description
string	The search identifier.

SelectedItem

Gets or sets the selected item.

Declaration

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

Property Value

Type	Description
object	The selected item.

SelectedItemChanged

Gets or sets the selected item changed.

Declaration

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

Property Value

Type	Description
EventCallback<object>	The selected item changed.

Separator

Gets or sets the item separator for Multiple dropdown.

Declaration

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

Property Value

Type	Description
string	Item separator

Template

Gets or sets the template.

Declaration

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

Property Value

Type	Description
RenderFragment<dynamic>	The template.

ValueProperty

Gets or sets the value property.

Declaration

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

Property Value

Type	Description
string	The value property.

View

Gets the view.

Declaration

protected override IEnumerable View { get; }

Property Value

Type	Description
IEnumerable	The view.

Overrides

DataBoundFormComponent<T>.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.

Declaration

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

Property Value

Type	Description
int

Virtualize

The Virtualize instance.

Declaration

public Virtualize<object> Virtualize { get; }

Property Value

Type	Description
Virtualize<object>

Methods

ClearAll()

Clears all.

Declaration

protected Task ClearAll()

Returns

Type	Description
Task

Dispose()

Disposes this instance.

Declaration

public override void Dispose()

Overrides

DataBoundFormComponent<T>.Dispose()

GetItemOrValueFromProperty(object, string)

Gets the item or value from property.

Declaration

public object GetItemOrValueFromProperty(object item, string property)

Parameters

Type	Name	Description
object	item	The item.
string	property	The property.

Returns

Type	Description
object	System.Object.

GetValue()

Gets the value.

Declaration

public override object GetValue()

Returns

Type	Description
object	System.Object.

Overrides

DataBoundFormComponent<T>.GetValue()

HandleKeyPress(KeyboardEventArgs, bool, bool?)

Handles the key press.

Declaration

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

Parameters

Type	Name	Description
KeyboardEventArgs	args	The KeyboardEventArgs instance containing the event data.
bool	isFilter	if set to true [is filter].
bool?	shouldSelectOnChange	Should select item on item change with keyboard.

Returns

Type	Description
Task

OnAfterRenderAsync(bool)

Called when [after render asynchronous].

Declaration

protected override Task OnAfterRenderAsync(bool firstRender)

Parameters

Type	Name	Description
bool	firstRender	if set to true [first render].

Returns

Type	Description
Task	Task.

Overrides

RadzenComponent.OnAfterRenderAsync(bool)

OnChange(ChangeEventArgs)

Handles the Change event.

Declaration

protected void OnChange(ChangeEventArgs args)

Parameters

Type	Name	Description
ChangeEventArgs	args	The ChangeEventArgs instance containing the event data.

OnDataChanged()

Called when [data changed].

Declaration

protected override Task OnDataChanged()

Returns

Type	Description
Task

Overrides

DataBoundFormComponent<T>.OnDataChanged()

OnFilter(ChangeEventArgs)

Handles the Filter event.

Declaration

protected virtual Task OnFilter(ChangeEventArgs args)

Parameters

Type	Name	Description
ChangeEventArgs	args	The ChangeEventArgs instance containing the event data.

Returns

Type	Description
Task

OnFilterKeyPress(KeyboardEventArgs)

Handles the FilterKeyPress event.

Declaration

protected virtual Task OnFilterKeyPress(KeyboardEventArgs args)

Parameters

Type	Name	Description
KeyboardEventArgs	args	The KeyboardEventArgs instance containing the event data.

Returns

Type	Description
Task

OnInitialized()

Called by the Blazor runtime.

Declaration

protected override void OnInitialized()

Overrides

RadzenComponent.OnInitialized()

OnKeyPress(KeyboardEventArgs, bool?)

Handles the KeyPress event.

Declaration

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

Parameters

Type	Name	Description
KeyboardEventArgs	args	The KeyboardEventArgs instance containing the event data.
bool?	shouldSelectOnChange	Should select item on item change with keyboard.

Returns

Type	Description
Task

OnParametersSet()

Base class of components that display a list of items.

Declaration

protected override void OnParametersSet()

Overrides

ComponentBase.OnParametersSet()

OnParametersSetAsync()

Called when [parameters set asynchronous].

Declaration

protected override Task OnParametersSetAsync()

Returns

Type	Description
Task	Task.

Overrides

ComponentBase.OnParametersSetAsync()

OnSelectItem(object, bool)

Called when [select item].

Declaration

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

Parameters

Type	Name	Description
object	item	The item.
bool	isFromKey	if set to true [is from key].

Returns

Type	Description
Task

OpenPopup(string, bool, bool)

Opens the popup.

Declaration

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

Parameters

Type	Name	Description
string	key	The key.
bool	isFilter	if set to true [is filter].
bool	isFromClick	if set to true [is from click].

Returns

Type	Description
Task

OpenPopupScript()

Opens the popup script.

Declaration

protected string OpenPopupScript()

Returns

Type	Description
string	System.String.

OpenPopupScriptFromParent()

Opens the popup script from parent.

Declaration

protected string OpenPopupScriptFromParent()

Returns

Type	Description
string	System.String.

Reset()

Resets this instance.

Declaration

public void Reset()

SelectAll()

Selects all.

Declaration

protected virtual Task SelectAll()

Returns

Type	Description
Task

SelectItem(object, bool)

Selects the item.

Declaration

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

Parameters

Type	Name	Description
object	item	The item.
bool	raiseChange	if set to true [raise change].

Returns

Type	Description
Task

SelectItemFromValue(object)

Selects the item from value.

Declaration

protected virtual void SelectItemFromValue(object value)

Parameters

Type	Name	Description
object	value	The value.

SetParametersAsync(ParameterView)

Set parameters as an asynchronous operation.

Declaration

public override Task SetParametersAsync(ParameterView parameters)

Parameters

Type	Name	Description
ParameterView	parameters	The parameters.

Returns

Type	Description
Task	A Task representing the asynchronous operation.

Overrides

DataBoundFormComponent<T>.SetParametersAsync(ParameterView)

Implements

IComponent

IHandleEvent

IHandleAfterRender

IDisposable

IRadzenFormComponent