Hello support team,

from the donut chart example under https://demos.telerik.com/blazor-ui/chart/donut-chart:

Is there a specific reason why all charts have a Template sub-property for the ChartSeriesTooltip construct but the Template field with the template syntax for the ChartSeriesLabels construct? I would favour a unified syntax for both of the properties, if this is possible somehow...

Is this planned for the future to be unified? Especially formatting like shown under https://docs.telerik.com/blazor-ui/knowledge-base/chart-format-percent is not as simple as I would have expected as nobody wants to touch JavaScript code literally :D (Also, localizing data seems quite difficult with that technique).

The best option in my opinion would be to remove those templates completely and just let the user decide what to show there while using a field called e.g. TooltipMappingName and LabelMappingName or something like that. This gives the chart the maximum of configuration possible.

Example:

<TelerikChart>
    <ChartTitle Text="What is you favourite sport?"></ChartTitle>
    <ChartLegend Visible="true" Position="ChartLegendPosition.Top"></ChartLegend>

    <ChartSeriesItems>
        <ChartSeries Type="ChartSeriesType.Donut"
                     Data="@Data"
                     Field="@nameof(ModelData.Value)"
                     CategoryField="@nameof(ModelData.Category)">
            <ChartSeriesTooltip Visible="true" Context="item" TooltipMappingName="@nameof(ModelData.Tooltip)"/>
            <ChartSeriesLabels Position="ChartSeriesLabelsPosition.OutsideEnd"
                               Visible="true"
                               Background="transparent"
                               LabelMappingName="@nameof(ModelData.Label)">
            </ChartSeriesLabels>
        </ChartSeries>
    </ChartSeriesItems>

</TelerikChart>

@code {
    public class ModelData
    {
        public string Category { get; set; }
        public int Value { get; set; }
  public string Tooltip { get; set; }
        public string Label { get; set; }
    }

    public List<ModelData> Data = new List<ModelData>()
    {
        new ModelData()
        {
            Category = "Football",
            Value = 35,
   Tooltip = "35%",
   Label = "Football: 35%"
        },
        new ModelData()
        {
            Category = "Basketball",
            Value = 25,
   Tooltip = "25%",
   Label = "Basketball: 25%"
        },
        new ModelData()
        {
            Category = "Volleyball",
            Value = 20,
   Tooltip = "20%",
   Label = "Volleyball: 20%"
        },
        new ModelData()
        {
            Category = "Rugby",
            Value = 10,
   Tooltip = "10%",
   Label = "Rugby: 10%"
        },
        new ModelData()
        {
            Category = "Tennis",
            Value = 10,
   Tooltip = "10%",
   Label = "Tennis: 10%"
        }
    };
}

Best regards,

Christian

The context DataItem is null for subsequent ChartSeries. It receives the correct object for the first ChartSeries, but for the rest is null. 

<Admin Edit>

A workaround, for the time being, would be to remove the Template and let the Tooltip display the default value, which will be correct.

</Admin Edit>

Reproduction code:

<TelerikChart>
    <ChartTitle Text="Unrecoverable Errors Per Minute vs. Signal Level" />
    <ChartCategoryAxes>
        <ChartCategoryAxis Type="@ChartCategoryAxisType.Category" />
    </ChartCategoryAxes>
    <ChartValueAxes>
        <ChartValueAxis>
            <ChartValueAxisLabels Visible="true" />
        </ChartValueAxis>
    </ChartValueAxes>

    <ChartTooltip Visible="true">
        <Template>
            @{
                var data = context.DataItem as ModelData;
                <div class="card" style="font-size: 0.8rem; color: black">
                    <span>@($"{data.Value}")</span>
                    <span>@($"{data.Type}")</span>

                </div>
            }
        </Template>
    </ChartTooltip>

    <ChartSeriesItems>
        <ChartSeries Type="ChartSeriesType.Line"
                     Data="@ChartData1"
                     CategoryField="@nameof(ModelData.Type)"
                     Field="@nameof(ModelData.Value)">
        </ChartSeries>
        <ChartSeries Type="ChartSeriesType.Line"
                     Data="@ChartData2"
                     CategoryField="@nameof(ModelData.Type)"
                     Field="@nameof(ModelData.Value)">
        </ChartSeries>
        <ChartSeries Type="ChartSeriesType.Line"
                     Data="@ChartData3"
                     CategoryField="@nameof(ModelData.Type)"
                     Field="@nameof(ModelData.Value)">
        </ChartSeries>
    </ChartSeriesItems>

</TelerikChart>

@code {
    public class ModelData
    {
        public string Type { get; set; }
        public double Value { get; set; }
    }

    public List<ModelData> ChartData1 = new List<ModelData>() { new ModelData() { Type = "S1", Value = 1 } };
    public List<ModelData> ChartData2 = new List<ModelData>() { new ModelData() { Type = "S2", Value = 5 } };
    public List<ModelData> ChartData3 = new List<ModelData>() { new ModelData() { Type = "S3", Value = 9 } };
}

The Chart Tooltip does not render correct values for the data points when the chart is bound to a model, has multiple series and Template is used. The DataItem does not seem to work as expected.

ADMIN EDIT:

If the Chart is bound with Independent Series Binding the FormattedValue will get the correct values.

If the Chart has no Template the correct values for the data points will be displayed

Hi!

I'm building a Blazor Component using your TelerikChart.  To build my chart, I'm dynamically inserting the series name and the series data, which is pulled from a list.  I also have a button on the page that changes the dataset (last month, this month, next month, etc).  The button will rebuild the list of names and data, and Blazor will build the chart with a 'foreach' entry in the ChartSeriesItems section of the Chart Component.

The problem is that the Items are not cleared each time.  When I click the button, I'm getting previous values. In the example below, I have 3 data sets.  The first has 4 items, the second has 8 and the third has 6.  If the user clicks the second, showing all 8, then clicks the first, the chart will show the new 4, and the previous 5-8 from the second set.  

 My chart description in HTML is:

... 
<ChartSeriesItems>
    @foreach(Tuple<string, object[]> t in myData)
    {
       <ChartSeries Type="ChartSeriesType.Column" Name=@t.Item1 Data=@t.Item2 />
    }
</ChartSeriesItems>
... 

I have checked my data through debugging to ensure that the myData variable is correct (i.e. when I click the first data, it only has 4 items).  However, when the chart displays, it shows 8 items. 

Is there a CLEARDATA method or something I can call on the Chart to ensure that the data is reset each time?  I see that there is a Clear() in JavaScript, but I'm writing in only Blazor and C#, with no JavaScript.

I've attached the .razor page for your reference.  (As this is my test code, I'm using random number generation to get the data.)

Thank you so much for your help!!

-Cheryl Simpson 

I would like to control the font of the Value axis labels in a similar fashion to the way I can control the labels of the category axis:

    <ChartCategoryAxes>
        <ChartCategoryAxis Categories="@xAxisItems">
            <ChartCategoryAxisLabels Font="bold 12px 'Helvetica'"></ChartCategoryAxisLabels>
        </ChartCategoryAxis>
    </ChartCategoryAxes>

*** Thread created by admin on customer behalf ***

Hi!

I'm more than a little impressed with your Blazor efforts to-date, but there's one component lacking: a CandleStick chart.

In need a chart that has a shaded area between a max and min set of curves, indicating the allowable area

Like this one: https://demos.telerik.com/kendo-ui/range-area-charts/index

The code below does not produce a chart series with a line that is 50 width?  What am i missing?

@page "/chartdemo"
Line series

<TelerikChart>
    <ChartSeriesItems>
        <ChartSeries Type="ChartSeriesType.Line" Name="Product 1" Data="@series1Data">
            <ChartSeriesMarkers Size="10"></ChartSeriesMarkers>
        </ChartSeries>
        <ChartSeries Type="ChartSeriesType.Line" Size="10" Name="Product 2" Data="@series2Data">
            <ChartSeriesLine Width="50"></ChartSeriesLine>
        </ChartSeries>
    </ChartSeriesItems>

    <ChartCategoryAxes>
        <ChartCategoryAxis Categories="@xAxisItems"></ChartCategoryAxis>
    </ChartCategoryAxes>

    <ChartTitle Text="Quarterly revenue per product"></ChartTitle>

    <ChartLegend Position="ChartLegendPosition.Right">
    </ChartLegend>
</TelerikChart>

@code {
    public List<object> series1Data = new List<object>() { 10, 2, 5, 6 };
    public List<object> series2Data = new List<object>() { 5, 8, 2, 7 };
    public string[] xAxisItems = new string[] { "Q1", "Q2", "Q3", "Q4" };

 }

The idea is to ensure labels don't render on top of each other. If series values are close to each other, labels start overlapping. Having tooltips will let me remove the labels.

Example:

Hi, I can't figure how to use the Min/Max properties of the ChartCategoryAxis because if I set these properties, the chart disappears.

Please help me.

@page "/"

<TelerikChart>

    <ChartSeriesItems>
        <ChartSeries Type="ChartSeriesType.Line" Name="Test" Data="@mesures"
                     Field="@nameof(Mesure.Value)" CategoryField="@nameof(Mesure.Date)" Aggregate="ChartSeriesAggregate.Sum">
        </ChartSeries>
    </ChartSeriesItems>

    <ChartCategoryAxes>
        <!-- This is OK -->
        @*<ChartCategoryAxis BaseUnit="ChartCategoryAxisBaseUnit.Hours" Type="ChartCategoryAxisType.Date" BaseUnitStep="1"></ChartCategoryAxis>*@

        <!-- This isn't : nothing is displayed -->
        <ChartCategoryAxis Min="@MinDate" Max="@MaxDate" BaseUnit="ChartCategoryAxisBaseUnit.Hours" Type="ChartCategoryAxisType.Date" BaseUnitStep="1"></ChartCategoryAxis>
    </ChartCategoryAxes>

</TelerikChart>

@code {

    private DateTime MinDate { get; set; } = new DateTime(2019, 01, 01, 13, 0, 0);
    private DateTime MaxDate { get; set; }   = new DateTime(2019, 01, 01, 17, 0, 0);

    public class Mesure
    {
        public DateTime Date { get; set; }
        public int Value { get; set; }
    }

    public List<Mesure> mesures = new List<Mesure>()
    {
        new Mesure() { Date = new DateTime(2019, 01, 01, 13, 0, 0), Value = 1 },
        new Mesure() { Date = new DateTime(2019, 01, 01, 14, 0, 0), Value = 2 },
        new Mesure() { Date = new DateTime(2019, 01, 01, 14, 30, 0), Value = 3 },
        new Mesure() { Date = new DateTime(2019, 01, 01, 14, 35, 0), Value = 4 },
        new Mesure() { Date = new DateTime(2019, 01, 01, 15, 0, 0), Value = 5 },
        new Mesure() { Date = new DateTime(2019, 01, 01, 16, 0, 0), Value = 6 },
        new Mesure() { Date = new DateTime(2019, 01, 01, 17, 0, 0), Value = 7 },
    };
}