Class DropDownListEvents<TValue, TItem>

Defines the SfDropDownList events of the component.

Inheritance

System.Object

DropDownListEvents<TValue, TItem>

Namespace: Syncfusion.Blazor.DropDowns

Assembly: Syncfusion.Blazor.dll

Syntax

public class DropDownListEvents<TValue, TItem> : OwningComponentBase

Type Parameters

Name	Description
TValue	A type which provides for the Value poperty type.
TItem	A type which provides data list schema for the dropdown list events.

Constructors

DropDownListEvents()

Declaration

public DropDownListEvents()

Properties

BaseParent

Specifies the base parent of the component.

Declaration

protected SfDropDownList<TValue, TItem> BaseParent { get; set; }

Property Value

Type
SfDropDownList<TValue, TItem>

Blur

Gets or sets the event callback that will be invoked when the dropdown list loses focus.

Declaration

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

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<System.Object>

Closed

Gets or sets the event callback that will be invoked after the dropdown popup has been closed.

Declaration

public EventCallback<ClosedEventArgs> Closed { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<ClosedEventArgs>

Created

Gets or sets the event callback that will be invoked when the component is created.

Declaration

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

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<System.Object>

DataBound

Gets or sets the event callback that will be invoked when data source is populated in the popup list.

Declaration

public EventCallback<DataBoundEventArgs> DataBound { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<DataBoundEventArgs>

Destroyed

Gets or sets the event callback that will be invoked when the component is destroyed.

Declaration

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

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<System.Object>

Filtering

Gets or sets the event callback that will be invoked on typing a character in the filter textbox.

Declaration

public EventCallback<FilteringEventArgs> Filtering { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<FilteringEventArgs>

Remarks

You can prevent the default filter action and make your query enable the PreventDefaultAction event argument, and pass the modify data source and query in FilterAsync(IEnumerable<TItem>, Query, FieldSettingsModel) method.

Examples

<SfDropDownList @ref="DDLObj" TItem="string" TValue="string" AllowFiltering="true" DataSource="@MyList">
    <DropDownListEvents TValue="string" TItem="string" Filtering="@OnFilteringHandler" />
</SfDropDownList>
@code{
    SfDropDownList<string, string> DDLObj { get; set; }
    protected List<string> MyList = new List<string>() { "Small", "Medium", "Large" };
    public async Task OnFilteringHandler(FilteringEventArgs args) {
        args.PreventDefaultAction = true;
        var query = new Query().Where(new WhereFilter() { Field = "Text", Operator = "contains", value = args.Text, IgnoreCase = true });
        await DDLObj.FilterAsync(MyList, query);
    }
  }

Focus

Gets or sets the event callback that will be invoked when the component is the focus.

Declaration

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

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<System.Object>

OnActionBegin

Gets or sets the event callback that will be invoked before fetching data from the data source.

Declaration

public EventCallback<ActionBeginEventArgs> OnActionBegin { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<ActionBeginEventArgs>

OnActionComplete

Gets or sets the evnet callback that will be invoked after data is fetched successfully from the data source.

Declaration

public EventCallback<ActionCompleteEventArgs<TItem>> OnActionComplete { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<ActionCompleteEventArgs<TItem>>

OnActionFailure

Gets or sets the event callback that will be invoked when the data fetch request fails.

Declaration

public EventCallback<Exception> OnActionFailure { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<System.Exception>

OnClose

Gets or sets the event callback that will be invoked before the dropdown popup is close.

Declaration

public EventCallback<PopupEventArgs> OnClose { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<PopupEventArgs>

Remarks

You can prevent the dropdown popup close action using Cancel and the popup remains opened always.

Examples

<SfDropDownList TItem="string" TValue="string" DataSource="@MyList">
    <DropDownListEvents TValue="string" TItem="string" OnClose="@OnCloseHandler"/>
</SfDropDownList>
@code{
    protected List<string> MyList = new List<string>() { "Small", "Medium", "Large" };
    public void OnCloseHandler(PopupEventArgs args) {
        args.Cancel = true;
    }
  }

OnOpen

Gets or sets the event callback that will be invoked when the dropdown popup before opens.

Declaration

public EventCallback<BeforeOpenEventArgs> OnOpen { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<BeforeOpenEventArgs>

Remarks

You can prevent the dropdown popup open action using Cancel.

Examples

<SfDropDownList TItem="string" TValue="string" DataSource="@MyList">
    <DropDownListEvents TValue="string" TItem="string" OnOpen="@OnOpenHandler"/>
</SfDropDownList>
@code{
    protected List<string> MyList = new List<string>() { "Small", "Medium", "Large" };
    public void OnOpenHandler(BeforeOpenEventArgs args) {
        args.Cancel = true;
    }
  }

OnResizeStart

Occurs when the resizing action of the popup begins.

Declaration

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

Property Value

Type	Description
Microsoft.AspNetCore.Components.EventCallback<System.Object>	An Microsoft.AspNetCore.Components.EventCallback<> that receives an event argument object containing resize start data.

Remarks

Use the OnResizeStart event to perform custom actions when the user initiates resizing of the popup. This event can be useful for setting initial states, logging, or displaying messages when resizing starts.

Examples

@code {
    private void HandleResizeStart(object args) {
        Console.WriteLine("Resizing has started.");
    }
}

OnResizeStop

Occurs when the resizing action of the popup is completed.

Declaration

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

Property Value

Type	Description
Microsoft.AspNetCore.Components.EventCallback<System.Object>	An Microsoft.AspNetCore.Components.EventCallback<> that receives an event argument object containing resize stop data.

Remarks

Use the OnResizeStop event to perform custom actions after the user has finished resizing the popup. This event is ideal for finalizing layout adjustments, saving state, or logging the final size of the popup.

Examples

@code {
    private void HandleResizeStop(object args) {
        Console.WriteLine("Resizing has stopped.");
    }
}

OnResizing

Occurs while the popup is being resized.

Declaration

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

Property Value

Type	Description
Microsoft.AspNetCore.Components.EventCallback<System.Object>	An Microsoft.AspNetCore.Components.EventCallback<> that receives an event argument object containing data during the resize process.

Remarks

The OnResizing event provides continuous feedback during the resizing action, allowing you to monitor changes to the popup size in real-time. This event can be useful for enforcing constraints, adjusting layouts, or providing visual feedback as the popup is resized.

Examples

@code {
    private void HandleResizing(object args) {
        Console.WriteLine("Currently resizing...");
    }
}

OnValueSelect

Gets or sets the event callback that will be when an item is selected from the dropdown popup by the user either with mouse/tap or with keyboard navigation.

Declaration

public EventCallback<SelectEventArgs<TItem>> OnValueSelect { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<SelectEventArgs<TItem>>

Remarks

You can prevent the item selection action using Cancel.

Examples

<SfDropDownList TItem="string" TValue="string" DataSource="@MyList">
    <DropDownListEvents TValue="string" TItem="string" OnValueSelect="@OnSelectHandler" />
</SfDropDownList>
@code{
    protected List<string> MyList = new List<string>() { "Small", "Medium", "Large" };
    public void OnSelectHandler(SelectEventArgs<string> args) {
        if(args.ItemData== "Medium")
            args.Cancel = true;
    }
  }

Opened

Gets or sets the event callback that will be invoked when the dropdown popup opens.

Declaration

public EventCallback<PopupEventArgs> Opened { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<PopupEventArgs>

ValueChange

Gets or sets the event callback that will be invoked when the Value property changed.

Declaration

public EventCallback<ChangeEventArgs<TValue, TItem>> ValueChange { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<ChangeEventArgs<TValue, TItem>>

Remarks

This event triggers when an item in a popup is selected or when the model value is changed by user.

Examples

<SfDropDownList TItem="string" TValue="string" DataSource="@MyList">
    <DropDownListEvents TValue="string" TItem="string" ValueChange="@OnChange"/>
</SfDropDownList>
@code{
    protected List<string> MyList = new List<string>() { "Small", "Medium", "Large" };
    public void OnChange(Syncfusion.Blazor.DropDowns.ChangeEventArgs<string, string> args) {
        var DDLValue = args.Value;
    }
  }

Methods

ComponentDispose(Boolean)

Declaration

protected void ComponentDispose(bool disposing)

Parameters

Type	Name	Description
System.Boolean	disposing