Data Visualization and Analysis — Tips and Tricks (August

This post includes a series of interesting support tickets answered throughout August and September. We hope you find the contents of this post interesting and of business value. Should you have any questions about a particular support ticket, feel free to post a comment in the DevExpress Support Center.

Tips & Tricks

BI Dashboard

T1113658 - How to add a watermark to the exported dashboard
https://supportcenter.devexpress.com/ticket/details/t1112628

BI Dashboard for Web Forms

T1112628 - How to hide the "Export To PDF" button for a particular widget
https://supportcenter.devexpress.com/ticket/details/t1094793
Handle the onItemCaptionToolbarUpdated event to customize the toolbar for a specific item. For example, if you need to remove the first export submenu for the Grid dashboard item ("gridDashboardItem1"), you can use the following code:
```
    function onItemCaptionToolbarUpdated(e) {
        if (e.itemName === "gridDashboardItem1") {
            var exportMenu = 
            	e.options.actionItems.find(item => item.name === 'export-menu');
            exportMenu.menu.items.splice(0, 1);
        }
    }
 
```
T1103211 - How to use Count and CountDistinct in calculated fields
https://supportcenter.devexpress.com/ticket/details/t1103211
T1109879 - How to use custom properties to customize Grid column options
https://supportcenter.devexpress.com/ticket/details/t1109879

BI Dashboard for WPF

T1117647 - How to add custom template to Series Labels of the Chart dashboard item
https://supportcenter.devexpress.com/ticket/details/t1117647

You can override ChartItemStyle to customize nested instances of the ChartControl and associated series options. The folowing code snippet modifies the SeriesLabel.ResolveOverlappingMode option:


private void ChartControl_BoundDataChanged(object sender, RoutedEventArgs e) {
    var chart = (ChartControl)sender;
    var d = (XYDiagram2D)chart.Diagram;

    for (int i = 0; i < d.Series.Count; i++) {
        var label = new SeriesLabel();
        label.ResolveOverlappingMode = ResolveOverlappingMode.HideOverlapped;
        label.ElementTemplate = (DataTemplate)this.FindResource("labelTemplate");
        d.Series[i].Label = label;
    }
}

<dx:ThemedWindow.Resources>
    <DataTemplate x:Key="labelTemplate">
        <Label Content="{Binding Path=Text}" Background="LightYellow" BorderThickness="0"/>
    </DataTemplate>
    <DataTemplate x:Key="chartTemplate">
        <dxc:ChartControl Style="{Binding Path=(dxdash:DashboardLayoutItem.ViewStyle), 
        	RelativeSource={RelativeSource TemplatedParent}}"
            BoundDataChanged="ChartControl_BoundDataChanged">
        </dxc:ChartControl>
    </DataTemplate>
</dx:ThemedWindow.Resources>
<Grid>
    <dxdash:DashboardControl x:Name="dashboardControl1">
        <dxdash:DashboardControl.ChartItemStyle>
            <Style TargetType="dxdash:ChartDashboardLayoutItem">
                <Setter Property="ContentTemplate" Value="{StaticResource chartTemplate}"/>
            </Style>
        </dxdash:DashboardControl.ChartItemStyle>
    </dxdash:DashboardControl>
</Grid>

Chart for WinForms

T1113940 - How to modify the color and size of the Heatmap cells
https://supportcenter.devexpress.com/ticket/details/t1113940

Chart for WPF

T1116213 - How to get the position of a point via a click event on a 2DChart using MVVM patterns
https://supportcenter.devexpress.com/ticket/details/t1116213

The correct MVVM approach is to use EventToCommand behavior. Event argument conversion is implemented in the CustomMouseButtonEventArgsConverter.Convert method.

<dxmvvm:Interaction.Behaviors>
    <dxmvvm:EventToCommand
    	Command="{Binding ClickCommand}"
        EventName="MouseDown"
        PassEventArgsToCommand="True"
        EventArgsConverter="{local:CustomMouseButtonEventArgsConverter}"/>
</dxmvvm:Interaction.Behaviors>


public ICommand ClickCommand { get; } = new DelegateCommand(OnClick);

private static void OnClick(Point coordinates) {
	MessageBox.Show(coordinates.ToString());
}

T1115869 - How to get selected item info on XYDiagram2D
https://supportcenter.devexpress.com/ticket/details/t1115869
T1112366 - How to display custom labels for logarithmic x-axis
https://supportcenter.devexpress.com/ticket/details/t1112366
To customize the display of axis labels, define Custom Labels as follows:
```
var label = new CustomAxisLabel(d.sieb, d.sieb.ToString());
((XYDiagram2D)chartControl2.Diagram).AxisX.CustomLabels.Add(label);
```