Class DropDownBase<T>

Base class of components that display a list of items.

Inheritance

System.Object

RadzenComponent

DataBoundFormComponent<T>

DropDownBase<T>

RadzenDropDown<TValue>

RadzenDropDownDataGrid<TValue>

RadzenListBox<TValue>

Implements

IDisposable

IRadzenFormComponent

Inherited Members

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>._view

DataBoundFormComponent<T>.EditContext

DataBoundFormComponent<T>.FieldIdentifier

DataBoundFormComponent<T>.ValueExpression

DataBoundFormComponent<T>.GetClassList(String)

DataBoundFormComponent<T>.FocusAsync()

DataBoundFormComponent<T>.FormFieldContext

DataBoundFormComponent<T>.CurrentPlaceholder

DataBoundFormComponent<T>.OnContextMenu(MouseEventArgs)

RadzenComponent.Attributes

RadzenComponent.Element

RadzenComponent.MouseEnter

RadzenComponent.MouseLeave

RadzenComponent.ContextMenu

RadzenComponent.Culture

RadzenComponent.DefaultCulture

RadzenComponent.OnMouseEnter()

RadzenComponent.OnMouseLeave()

RadzenComponent.OnContextMenu(Microsoft.AspNetCore.Components.Web.MouseEventArgs)

RadzenComponent.Style

RadzenComponent.Visible

RadzenComponent.GetCssClass()

RadzenComponent.GetId()

RadzenComponent.GetComponentCssClass()

RadzenComponent.Debounce(Func<Task>, Int32)

RadzenComponent.UniqueID

RadzenComponent.JSRuntime

RadzenComponent.IsJSRuntimeAvailable

RadzenComponent.Reference

RadzenComponent.RaiseContextMenu(Microsoft.AspNetCore.Components.Web.MouseEventArgs)

RadzenComponent.RaiseMouseEnter()

RadzenComponent.RaiseMouseLeave()

RadzenComponent.CurrentStyle

Namespace: Radzen

Assembly: Radzen.Blazor.dll

Syntax

public class DropDownBase<T> : DataBoundFormComponent<T>, IDisposable, IRadzenFormComponent

Type Parameters

Name	Description
T

Fields

list

The list

Declaration

protected ElementReference? list

Field Value

Type	Description
System.Nullable<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
System.Int32

selectedItem

The selected item

Declaration

protected object selectedItem

Field Value

Type	Description
System.Object

selectedItems

The selected items

Declaration

protected ISet<object> selectedItems

Field Value

Type	Description
ISet<System.Object>

Properties

AllowClear

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

Declaration

public bool AllowClear { get; set; }

Property Value

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

AllowFiltering

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

Declaration

public virtual bool AllowFiltering { get; set; }

Property Value

Type	Description
System.Boolean	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

public bool AllowSelectAll { get; set; }

Property Value

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

AllowVirtualization

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

Declaration

public bool AllowVirtualization { get; set; }

Property Value

Type	Description
System.Boolean

Count

Specifies the total number of items in the data source.

Declaration

public int Count { get; set; }

Property Value

Type	Description
System.Int32

Data

Gets or sets the data.

Declaration

public override IEnumerable Data { get; set; }

Property Value

Type	Description
IEnumerable	The data.

Overrides

Radzen.DataBoundFormComponent<T>.Data

DisabledProperty

Gets or sets the disabled property.

Declaration

public string DisabledProperty { get; set; }

Property Value

Type	Description
System.String	The disabled property.

EmptyAriaLabel

Gets or sets the empty value aria label text.

Declaration

public string EmptyAriaLabel { get; set; }

Property Value

Type	Description
System.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

public virtual bool FilterAsYouType { get; set; }

Property Value

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

FilterDelay

Gets or sets the filter delay.

Declaration

public int FilterDelay { get; set; }

Property Value

Type	Description
System.Int32	The filter delay.

HasValue

Gets a value indicating whether this instance has value.

Declaration

public override bool HasValue { get; }

Property Value

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

Overrides

Radzen.DataBoundFormComponent<T>.HasValue

HeaderTemplate

Gets or sets the header template.

Declaration

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

public IEqualityComparer<object> ItemComparer { get; set; }

Property Value

Type	Description
IEqualityComparer<System.Object>

Items

Gets the items.

Declaration

protected virtual IEnumerable<object> Items { get; }

Property Value

Type	Description
IEnumerable<System.Object>	The items.

Multiple

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

Declaration

public bool Multiple { get; set; }

Property Value

Type	Description
System.Boolean	true if multiple; otherwise, false.

PageSize

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

Declaration

public int PageSize { get; set; }

Property Value

Type	Description
System.Int32

PopupID

Gets the popup identifier.

Declaration

protected string PopupID { get; }

Property Value

Type	Description
System.String	The popup identifier.

RemoveChipTitle

Gets or sets the remove chip button title.

Declaration

public string RemoveChipTitle { get; set; }

Property Value

Type	Description
System.String	The remove chip button title.

SearchAriaLabel

Gets or sets the search aria label text.

Declaration

public string SearchAriaLabel { get; set; }

Property Value

Type	Description
System.String	The search aria label text.

SearchID

Gets the search identifier.

Declaration

public string SearchID { get; }

Property Value

Type	Description
System.String	The search identifier.

SelectedItem

Gets or sets the selected item.

Declaration

public object SelectedItem { get; set; }

Property Value

Type	Description
System.Object	The selected item.

SelectedItemChanged

Gets or sets the selected item changed.

Declaration

public EventCallback<object> SelectedItemChanged { get; set; }

Property Value

Type	Description
EventCallback<System.Object>	The selected item changed.

Separator

Gets or sets the item separator for Multiple dropdown.

Declaration

public string Separator { get; set; }

Property Value

Type	Description
System.String	Item separator

Template

Gets or sets the template.

Declaration

public RenderFragment<dynamic> Template { get; set; }

Property Value

Type	Description
RenderFragment<System.Object>	The template.

ValueProperty

Gets or sets the value property.

Declaration

public string ValueProperty { get; set; }

Property Value

Type	Description
System.String	The value property.

View

Gets the view.

Declaration

protected override IEnumerable View { get; }

Property Value

Type	Description
IEnumerable	The view.

Overrides

Radzen.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

public int VirtualizationOverscanCount { get; set; }

Property Value

Type	Description
System.Int32

Virtualize

The Virtualize instance.

Declaration

public Microsoft.AspNetCore.Components.Web.Virtualization.Virtualize<object> Virtualize { get; }

Property Value

Type	Description
Microsoft.AspNetCore.Components.Web.Virtualization.Virtualize<System.Object>

Methods

ClearAll()

Clears all.

Declaration

protected async System.Threading.Tasks.Task ClearAll()

Returns

Type	Description
System.Threading.Tasks.Task

Dispose()

Disposes this instance.

Declaration

public override void Dispose()

Overrides

Radzen.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
System.Object	item	The item.
System.String	property	The property.

Returns

Type	Description
System.Object	System.Object.

GetValue()

Gets the value.

Declaration

public override object GetValue()

Returns

Type	Description
System.Object	System.Object.

Overrides

Radzen.DataBoundFormComponent<T>.GetValue()

HandleKeyPress(Microsoft.AspNetCore.Components.Web.KeyboardEventArgs, Boolean, Nullable<Boolean>)

Handles the key press.

Declaration

protected virtual async System.Threading.Tasks.Task HandleKeyPress(Microsoft.AspNetCore.Components.Web.KeyboardEventArgs args, bool isFilter = false, bool? shouldSelectOnChange = null)

Parameters

Type	Name	Description
Microsoft.AspNetCore.Components.Web.KeyboardEventArgs	args	The instance containing the event data.
System.Boolean	isFilter	if set to true [is filter].
System.Nullable<System.Boolean>	shouldSelectOnChange	Should select item on item change with keyboard.

Returns

Type	Description
System.Threading.Tasks.Task

OnAfterRenderAsync(Boolean)

Called when [after render asynchronous].

Declaration

protected override Task OnAfterRenderAsync(bool firstRender)

Parameters

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

Returns

Type	Description
Task	Task.

Overrides

RadzenComponent.OnAfterRenderAsync(Boolean)

OnChange(ChangeEventArgs)

Handles the Change event.

Declaration

protected void OnChange(ChangeEventArgs args)

Parameters

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

OnDataChanged()

Called when [data changed].

Declaration

protected override async Task OnDataChanged()

Returns

Type	Description
Task

Overrides

Radzen.DataBoundFormComponent<T>.OnDataChanged()

OnFilter(ChangeEventArgs)

Handles the Filter event.

Declaration

protected virtual async System.Threading.Tasks.Task OnFilter(ChangeEventArgs args)

Parameters

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

Returns

Type	Description
System.Threading.Tasks.Task

OnFilterKeyPress(Microsoft.AspNetCore.Components.Web.KeyboardEventArgs)

Handles the FilterKeyPress event.

Declaration

protected virtual async System.Threading.Tasks.Task OnFilterKeyPress(Microsoft.AspNetCore.Components.Web.KeyboardEventArgs args)

Parameters

Type	Name	Description
Microsoft.AspNetCore.Components.Web.KeyboardEventArgs	args	The instance containing the event data.

Returns

Type	Description
System.Threading.Tasks.Task

OnInitialized()

Called by the Blazor runtime.

Declaration

protected override void OnInitialized()

Overrides

RadzenComponent.OnInitialized()

OnKeyPress(Microsoft.AspNetCore.Components.Web.KeyboardEventArgs, Nullable<Boolean>)

Handles the KeyPress event.

Declaration

protected virtual async System.Threading.Tasks.Task OnKeyPress(Microsoft.AspNetCore.Components.Web.KeyboardEventArgs args, bool? shouldSelectOnChange = null)

Parameters

Type	Name	Description
Microsoft.AspNetCore.Components.Web.KeyboardEventArgs	args	The instance containing the event data.
System.Nullable<System.Boolean>	shouldSelectOnChange	Should select item on item change with keyboard.

Returns

Type	Description
System.Threading.Tasks.Task

OnParametersSet()

Declaration

protected override void OnParametersSet()

OnParametersSetAsync()

Called when [parameters set asynchronous].

Declaration

protected override Task OnParametersSetAsync()

Returns

Type	Description
Task	Task.

OnSelectItem(Object, Boolean)

Called when [select item].

Declaration

protected virtual async System.Threading.Tasks.Task OnSelectItem(object item, bool isFromKey = false)

Parameters

Type	Name	Description
System.Object	item	The item.
System.Boolean	isFromKey	if set to true [is from key].

Returns

Type	Description
System.Threading.Tasks.Task

OpenPopup(String, Boolean, Boolean)

Opens the popup.

Declaration

protected virtual async System.Threading.Tasks.Task OpenPopup(string key = "ArrowDown", bool isFilter = false, bool isFromClick = false)

Parameters

Type	Name	Description
System.String	key	The key.
System.Boolean	isFilter	if set to true [is filter].
System.Boolean	isFromClick	if set to true [is from click].

Returns

Type	Description
System.Threading.Tasks.Task

OpenPopupScript()

Opens the popup script.

Declaration

protected string OpenPopupScript()

Returns

Type	Description
System.String	System.String.

OpenPopupScriptFromParent()

Opens the popup script from parent.

Declaration

protected string OpenPopupScriptFromParent()

Returns

Type	Description
System.String	System.String.

Reset()

Resets this instance.

Declaration

public void Reset()

SelectAll()

Selects all.

Declaration

protected virtual async System.Threading.Tasks.Task SelectAll()

Returns

Type	Description
System.Threading.Tasks.Task

SelectItem(Object, Boolean)

Selects the item.

Declaration

public async System.Threading.Tasks.Task SelectItem(object item, bool raiseChange = true)

Parameters

Type	Name	Description
System.Object	item	The item.
System.Boolean	raiseChange	if set to true [raise change].

Returns

Type	Description
System.Threading.Tasks.Task

SelectItemFromValue(Object)

Selects the item from value.

Declaration

protected virtual void SelectItemFromValue(object value)

Parameters

Type	Name	Description
System.Object	value	The value.

SetParametersAsync(ParameterView)

Set parameters as an asynchronous operation.

Declaration

public override async Task SetParametersAsync(ParameterView parameters)

Parameters

Type	Name	Description
ParameterView	parameters	The parameters.

Returns

Type	Description
Task	A Task representing the asynchronous operation.

Overrides

Radzen.DataBoundFormComponent<T>.SetParametersAsync(ParameterView)

Implements

IDisposable

IRadzenFormComponent