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V24.2

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DxChartBase.TooltipShowing Event

Fires before a tooltip appears.

Namespace: DevExpress.Blazor

Assembly: DevExpress.Blazor.v24.2.dll

NuGet Package: DevExpress.Blazor

#Declaration

C#
[Parameter]
public EventCallback<ChartTooltipShowingEventArgs> TooltipShowing { get; set; }

#Event Data

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

Property Description
Cancel Gets or sets a value indicating whether the event should be canceled. Inherited from CancelEventArgs.
TooltipInfo Returns information about the tooltip that is about to appear.

#Remarks

Add a DxChartTooltip object to chart markup and set the DxChartTooltip.Enabled property to true to enable tooltip functionality.

The chart component raises the TooltipShowing event in the following cases:

In the event handler, use the TooltipInfo argument property to get information about the tooltip that is about to appear.

You can also set the event’s Cancel argument property to true to disable tooltip functionality for individual series points.

The following code snippet disables tooltips for series points that correspond to the specified series:

<DxChart Data="@SalesData"
         TooltipShowing="@OnTooltipShowing">
    <DxChartLineSeries Name="2017"
                       Filter="@((SaleInfo s) => s.Date.Year == 2017)"
                       ArgumentField="@(s => s.City)"
                       ValueField="@(s => s.Amount)"
                       SummaryMethod="Enumerable.Sum" />
    <DxChartLineSeries Name="2018"
                       Filter="@((SaleInfo s) => s.Date.Year == 2018)"
                       ArgumentField="@(s => s.City)"
                       ValueField="@(s => s.Amount)"
                       SummaryMethod="Enumerable.Sum" />
    <DxChartLegend AllowToggleSeries="true" 
                   Orientation="Orientation.Vertical"
                   Position="RelativePosition.Outside"
                   HorizontalAlignment="HorizontalAlignment.Right">
        <DxChartTitle Text="Years" />
    </DxChartLegend>
    <DxChartTooltip Enabled="true" />
</DxChart>

@code {
    void OnTooltipShowing(ChartTooltipShowingEventArgs e) {
        if (e.TooltipInfo.Series.Name == "2017")
            e.Cancel = true;
    }

    IEnumerable<SaleInfo> SalesData;
    protected override async Task OnInitializedAsync() {
        SalesData = await Sales.GetSalesAsync();
    }
}
See Also