DxChart<T>.VisualRangeChanged Event

Fires when the axis visual range changes.

Namespace: DevExpress.Blazor

Assembly: DevExpress.Blazor.v25.1.dll

NuGet Package: DevExpress.Blazor

Declaration

[Parameter]
public EventCallback<ChartVisualRangeChangedEventArgs> VisualRangeChanged { get; set; }

Event Data

The VisualRangeChanged event's data class is ChartVisualRangeChangedEventArgs. The following properties provide information specific to this event:

Property	Description
AxisName	Returns the name of the value axis or null for the argument axis.
ChangeSource	Identifies an operation that triggered the event.
CurrentRange	Returns the new axis visual range.
IsArgumentAxis	Returns whether an argument or value axis is processed.
PreviousRange	Returns the previous axis visual range.

Remarks

Handle the VisualRangeChanged event to react to axis visual range changes. This event fires in the following cases:

• Users zoom or pan the chart.
• You apply specific visual ranges to axes using SetArgumentAxisVisualRange and SetValueAxisVisualRange methods.
• You reset visual ranges for all axes using the ResetVisualRange method.

The event includes the following arguments:

PreviousRange | CurrentRange

Return previous and current axis visual ranges.

IsArgumentAxis

Identifies the axis (argument or value).

AxisName

Returns the name of the value axis whose visual range changes. If you do not specify the value axis name in chart markup, the property returns the axis position. In the case of the argument axis, returns null.

ChangeSource

Identifies the operation that causes range changes (zoom/pan action or method call).

Example

The following code snippet shows information about visual range changes only when a user pans the chart along the value axis:

@inject ICurrencyExchangeDataProvider UsdJpyDataProvider

<DxChart @ref="@chart"
         T="DatePricePoint"
         Data="@UsdJpyData"
         VisualRangeChanged="@OnVisualRangeChanged"
         Width="100%">
    <DxChartLineSeries T="DatePricePoint"
                       TArgument="DateTime"
                       TValue="double"
                       ArgumentField="i => i.DateTimeStamp"
                       ValueField="i => i.Price"
                       Name="USDJPY">
        <DxChartSeriesPoint Visible="false" />
        <DxChartAggregationSettings Enabled="true"
                                    Method="ChartAggregationMethod.Average" />
    </DxChartLineSeries>
    <DxChartArgumentAxis>
        <DxChartAxisRange StartValue="startDate"
                          EndValue="endDate" />
    </DxChartArgumentAxis>
    <DxChartZoomAndPanSettings ValueAxisZoomAndPanMode="ChartAxisZoomAndPanMode.Both"
                                ArgumentAxisZoomAndPanMode="ChartAxisZoomAndPanMode.Both"/>
    <DxChartScrollBarSettings ArgumentAxisScrollBarVisible="true"
                              ArgumentAxisScrollBarPosition="ChartScrollBarPosition.Bottom" />
</DxChart>

@code {
    IEnumerable<DatePricePoint> UsdJpyData;
    DxChart<DatePricePoint> chart;

    DateTime startDate = new DateTime(2020, 01, 01);
    DateTime endDate = new DateTime(2021, 01, 29);

    void OnVisualRangeChanged(ChartVisualRangeChangedEventArgs args) {
        if (!args.IsArgumentAxis && args.ChangeSource == ChartVisualRangeChangeSource.ZoomAction) {
            var previousRange = args.PreviousRange;
            var currentRange = args.CurrentRange;
            ShowDetailDialog(previousRange, currentRange);
        }
    }
    // ...

    protected override async Task OnInitializedAsync() {
        UsdJpyData = await UsdJpyDataProvider.GetDataAsync();
    }
}