Blazor Tree Grid Summaries

    The Ignite UI for Blazor Summaries feature in Blazor Tree Grid functions on a per-column level as group footer. Blazor TreeGrid summaries is powerful feature which enables the user to see column information in a separate container with a predefined set of default summary items, depending on the type of data within the column or by implementing a custom template in the IgbTreeGrid.

    Blazor Tree Grid Summaries Overview Example

    [!Note] The summary of the column is a function of all column values, unless filtering is applied, then the summary of the column will be function of the filtered result values

    IgbTreeGrid summaries can also be enabled on a per-column level in Ignite UI for Blazor, which means that you can activate it only for columns that you need. IgbTreeGrid summaries gives you a predefined set of default summaries, depending on the type of data in the column, so that you can save some time:

    For string and boolean DataType, the following function is available:

    • Count

    For number, currency and percent data types, the following functions are available:

    • Count
    • Min
    • Max
    • Average
    • Sum

    For date data type, the following functions are available:

    • Count
    • Earliest
    • Latest

    All available column data types could be found in the official Column types topic.

    IgbTreeGrid summaries are enabled per-column by setting HasSummary property to true. It is also important to keep in mind that the summaries for each column are resolved according to the column data type. In the IgbTreeGrid the default column data type is string, so if you want number or date specific summaries you should specify the DataType property as number or date. Note that the summary values will be displayed localized, according to the grid Locale and column PipeArgs.

    <IgbTreeGrid>
        <IgbColumn Field="ID" Header="Order ID"></IgbColumn>
        <IgbColumn Field="Name" Header="Order Product" HasSummary="true"></IgbColumn>
        <IgbColumn Field="Units" Header="Units" HasSummary="true"></IgbColumn>
</IgbTreeGrid>

    The other way to enable/disable summaries for a specific column or a list of columns is to use the public method EnableSummaries/DisableSummaries of the IgbTreeGrid.

    <IgbTreeGrid AutoGenerate="false" Data="OrdersTreeData" Name="treeGrid" @ref="treeGridRef" Id="treeGrid" PrimaryKey="ID">
    <IgbColumn Field="ID" Header="Order ID"></IgbColumn>
    <IgbColumn Field="Name" Header="Order Product" HasSummary="true"></IgbColumn>
    <IgbColumn Field="Units" Header="Units" DataType="GridColumnDataType.Number" HasSummary="true"></IgbColumn>
</IgbTreeGrid>

@code {
    public async void DisableSummaries()
    {
        object[] disabledSummaries = { "Units" };
        await this.treeGrid.DisableSummariesAsync(disabledSummaries);
    }
}

    Custom Tree Grid Summaries

    If these functions do not fulfill your requirements you can provide a custom summary for the specific columns.

    
//In JavaScript
class PtoSummary {
    operate(data, allData, fieldName) {
        const result = [];
        result.push({
            key: 'totalOnPTO',
            label: 'Employees On PTO',
            summaryResult: this.count(allData.filter((rec) => rec['OnPTO']).map(r => r[fieldName]))
        });
        result.push({
            key: 'devs',
            label: 'Developers',
            summaryResult: this.count(allData.filter((rec) => rec[fieldName].includes('Developer') && rec['OnPTO']).map(r => r[fieldName]))
        });
        result.push({
            key: 'tl',
            label: 'Team Leads',
            summaryResult: this.count(allData.filter((rec) => rec[fieldName].includes('Team Lead') && rec['OnPTO']).map(r => r[fieldName]))
        });
        result.push({
            key: 'managers',
            label: 'Managers/Directors',
            summaryResult: this.count(allData.filter((rec) => (rec[fieldName].includes('Manager') || rec[fieldName].includes('Director')) && rec['OnPTO']).map(r => r[fieldName]))
        });
        result.push({
            key: 'ceo',
            label: 'CEO/President',
            summaryResult: this.count(allData.filter((rec) => (rec[fieldName].includes('CEO') || rec[fieldName].includes('President')) && rec['OnPTO']).map(r => r[fieldName]))
        });
        return result;
    }
}

    As seen in the examples, the base classes expose the Operate method, so you can choose to get all default summaries and modify the result, or calculate entirely new summary results.

    The method returns a list of IgbSummaryResult.

    and take optional parameters for calculating the summaries. See Custom summaries, which access all data section below.

    [!Note] In order to calculate the summary row height properly, the Tree Grid needs the Operate method to always return an array of IgbSummaryResult with the proper length even when the data is empty.

    <IgbTreeGrid 
        AutoGenerate="true"
        Name="treeGrid"
        @ref="treeGrid"
        Data="EmployeesFlatData"
        PrimaryKey="ID"
        ColumnInitScript="WebTreeGridCustomSummary">
</IgbTreeGrid>

// In Javascript
igRegisterScript("WebTreeGridCustomSummary", (event) => {
    if (event.detail.field === "Title") {
        event.detail.summaries = PtoSummary;
    }
}, false);

    Custom summaries, which access all data

    Now you can access all Tree Grid data inside the custom column summary. Two additional optional parameters are introduced in the SummaryOperand Operate method. As you can see in the code snippet below the operate method has the following three parameters:

    • columnData - gives you an array that contains the values only for the current column
    • allGridData - gives you the whole grid data source
    • fieldName - current column field
    class PtoSummary {
    operate(data, allData, fieldName) {
        const result = [];
        result.push({
            key: 'totalOnPTO',
            label: 'Employees On PTO',
            summaryResult: this.count(allData.filter((rec) => rec['OnPTO']).map(r => r[fieldName]))
        });
        return result;
    }
}

    Summary Template

    SummaryTemplate targets the column summary providing as a context the column summary results.

    <IgbColumn HasSummary="true" SummaryTemplateScript="SummaryTemplate">
</IgbColumn>

igRegisterScript("SummaryTemplate", (ctx) => {
    var html = window.igTemplating.html;
    return html`<div>
    <span> ${ctx.implicit[0].label} - ${ctx.implicit[0].summaryResult} </span>
</div>`
}, false);

    When a default summary is defined, the height of the summary area is calculated by design depending on the column with the largest number of summaries and the --ig-size of the grid. Use the SummaryRowHeight input property to override the default value. As an argument it expects a number value, and setting a falsy value will trigger the default sizing behavior of the grid footer.

    Disabled Summaries

    The DisabledSummaries property provides precise per-column control over the Blazor Tree Grid summary feature. This property enables users to customize the summaries displayed for each column in the TreeGrid, ensuring that only the most relevant and meaningful data is shown. For example, you can exclude specific summary types, such as ['count', 'min', 'max'] by specifying their summary keys in an array.

    This property can also be modified dynamically at runtime through code, providing flexibility to adapt the TreeGrid's summaries to changing application states or user actions.

    The following examples illustrate how to use the DisabledSummaries property to manage summaries for different columns and exclude specific default and custom summary types in the Blazor Tree Grid:

    <!-- Disable default summaries -->
<IgbColumn 
    Field="UnitPrice" 
    Header="Unit Price" 
    DataType="GridColumnDataType.Number"
    HasSummary="true" 
    DisabledSummaries="['count', 'sum', 'average']" />

<!-- Disable custom summaries -->
<IgbColumn 
    Field="UnitsInStock" 
    Header="Units In Stock" 
    DataType="GridColumnDataType.Number"
    HasSummary="true" 
    Summaries="discontinuedSummary" 
    DisabledSummaries="['discontinued', 'totalDiscontinued']" />

    For UnitPrice, default summaries like count, sum, and average are disabled, leaving others like min and max active.

    For UnitsInStock, custom summaries such as discontinued and totalDiscontinued are excluded using the DisabledSummaries property.

    At runtime, summaries can also be dynamically disabled using the DisabledSummaries property. For example, you can set or update the property on specific columns programmatically to adapt the displayed summaries based on user actions or application state changes.

    Child Summaries

    The IgbTreeGrid supports separate summaries for the root nodes and for each nested child node level. Which summaries are shown is configurable using the SummaryCalculationMode property. The child level summaries can be shown before or after the child nodes using the SummaryPosition property. Along with these two properties the IgbTreeGrid exposes and ShowSummaryOnCollapse property which allows you to determine whether the summary row stays visible when the parent node that refers to is collapsed.

    The available values of the SummaryCalculationMode property are:

    • RootLevelOnly - Summaries are calculated only for the root level nodes.
    • ChildLevelsOnly - Summaries are calculated only for the child levels.
    • RootAndChildLevels - Summaries are calculated for both root and child levels. This is the default value.

    The available values of the SummaryPosition property are:

    • Top - The summary row appears before the list of child rows.
    • Bottom - The summary row appears after the list of child rows. This is the default value.

    The ShowSummaryOnCollapse property is boolean. Its default value is set to false, which means that the summary row would be hidden when the parent row is collapsed. If the property is set to true the summary row stays visible when parent row is collapsed.

    [!Note] The SummaryPosition property applies only for the child level summaries. The root level summaries appear always fixed at the bottom of the IgbTreeGrid.

    Keyboard Navigation

    The summary rows can be navigated with the following keyboard interactions:

    • UP - navigates one cell up.
    • DOWN - navigates one cell down.
    • LEFT - navigates one cell left.
    • RIGHT - navigates one cell right.
    • CTRL + LEFT or HOME - navigates to the leftmost cell.
    • CTRL + RIGHT or END - navigates to the rightmost cell.

    Styling

    In addition to the predefined themes, the grid could be further customized by setting some of the available CSS properties. In case you would like to change some of the colors, you need to set a class for the grid first:

    <IgbTreeGrid class="grid"></IgbTreeGrid>

    Then set the related CSS properties for that class:

    .grid {
    --ig-grid-summary-background-color:#e0f3ff;
    --ig-grid-summary-focus-background-color: rgba( #94d1f7, .3 );
    --ig-grid-summary-label-color: rgb(228, 27, 117);
    --ig-grid-summary-result-color: black;
}

    Demo

    API References

    Additional Resources

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