Filter Panel and Filter Builder Dialog in Blazor TreeList

• Dec 12, 2025
• 20 minutes to read

The DevExpress Blazor TreeList component includes a built-in filter panel and filter builder dialog. The panel displays the current filter condition and provides controls to temporarily disable or clear it. Users can click the condition to open the filter builder dialog, where they can edit and combine filter criteria for TreeList columns.

Run Demo: Filter Panel Run Demo: Filter Builder Customization

Add a Filter Panel

Assign Auto to FilterPanelDisplayMode to display the filter panel only when TreeList data is filtered. To always display the filter panel, set the FilterPanelDisplayMode property to Always:

Razor

@inject EmployeeTaskService EmployeeTaskService

<DxTreeList Data="TreeListData" KeyFieldName="Id" ParentKeyFieldName="ParentId"
            FilterMenuButtonDisplayMode="TreeListFilterMenuButtonDisplayMode.Always"
            FilterPanelDisplayMode="TreeListFilterPanelDisplayMode.Always">
    <Columns>
        <DxTreeListDataColumn FieldName="Name" Caption="Task" />
        <DxTreeListDataColumn FieldName="EmployeeName" Caption="Assigned To" />
        <DxTreeListDataColumn FieldName="StartDate" />
        <DxTreeListDataColumn FieldName="DueDate" />
        <DxTreeListDataColumn FieldName="Priority">
            <EditSettings>
                <DxComboBoxSettings Data="Priorities" ValueFieldName="Value" TextFieldName="Text" />
            </EditSettings>
        </DxTreeListDataColumn>
        <DxTreeListDataColumn Caption="Progress" FieldName="Status">
            <CellDisplayTemplate>
                <DxProgressBar Value="Convert.ToDouble(context.Value)" Thickness="0.875em" Size="100%"
                            MinValue="0" MaxValue="100" ShowLabel="false" />
            </CellDisplayTemplate>
        </DxTreeListDataColumn>
    </Columns>
</DxTreeList>

@code {
    List<EmployeeTask> TreeListData { get; set; }

    protected override void OnInitialized() {
        TreeListData = EmployeeTaskService.GenerateData();
    }
    record Priority(int Value, string Text);
    static readonly IReadOnlyList<Priority> Priorities = new Priority[] {
        new Priority(-1, "Low"),
        new Priority(0, "Medium"),
        new Priority(1, "High"),
    };
}

EmployeeTask.cs

public class EmployeeTask {
    public int Id { get; set; }
    public int ParentId { get; set; }
    public string Name { get; set; }
    public string EmployeeName { get; set; }
    public DateTime StartDate { get; set; }
    public DateTime DueDate { get; set; }
    public int Progress { get; set; }
    public EmployeeTask() { }
    public EmployeeTask(
        int id,
        int parentId,
        string name,
        string employeeName,
        DateTime startDate,
        DateTime dueDate,
        int progress
        )
    {
        Id = id;
        ParentId = parentId;
        Name = name;
        EmployeeName = employeeName;
        StartDate = startDate;
        DueDate = dueDate;
        Progress = progress;
    }
}

EmployeeTaskService.cs

public class EmployeeTaskService {
    public List<EmployeeTask> GenerateData() {
        return new List<EmployeeTask>() {
            new EmployeeTask(1, 0, "Simplify & Clarify Product Messaging", "John Heart", new DateTime(2018, 4, 3), new DateTime(2018, 4, 14), 14),
            new EmployeeTask(2, 1, "Prepare Financial Reports", "Samantha Bright", new DateTime(2018, 4, 3), new DateTime(2018, 4, 7), 17),
            new EmployeeTask(3, 1, "Prepare Marketing Plan", "Arthur Miller", new DateTime(2018, 4, 7), new DateTime(2018, 4, 14), 11),
            new EmployeeTask(4, 0, "Create Action Plan to Improve Customer Engagement", "Robert Reagan", new DateTime(2017, 8, 8), new DateTime(2018, 4, 8), 23),
            new EmployeeTask(5, 4, "Update Personnel Files", "Greta Sims", new DateTime(2017, 8, 8), new DateTime(2017, 10, 18), 100),
            new EmployeeTask(6, 4, "Review Health Insurance Options", "Brett Wade", new DateTime(2017, 9, 27), new DateTime(2017, 11, 10), 37),
            new EmployeeTask(7, 4, "Choose Between PPO and HMO Health Plan", "Sandra Johnson", new DateTime(2017, 12, 13), new DateTime(2018, 3, 23), 17),
            new EmployeeTask(8, 4, "Update Google Adwords Strategy", "Ed Holmes", new DateTime(2017, 8, 23), new DateTime(2017, 12, 23), 45),
            new EmployeeTask(9, 4, "Create New Brochure Design", "Barb Banks", new DateTime(2018, 1, 3), new DateTime(2018, 3, 14), 17),
            new EmployeeTask(10, 4, "Obtain Price Quote for New Brochure", "Kevin Carter", new DateTime(2018, 2, 1), new DateTime(2018, 3, 15), 18),
            new EmployeeTask(11, 4, "Brochure Design Review", "Cindy Stanwick", new DateTime(2017, 8, 22), new DateTime(2017, 10, 28), 4),
            new EmployeeTask(12, 4, "Review Website Redesign Strategy", "Sammy Hill", new DateTime(2017, 9, 16), new DateTime(2018, 3, 6), 73),
            new EmployeeTask(13, 4, "Roll Out New Website", "Davey Jones", new DateTime(2017, 11, 7), new DateTime(2018, 2, 6), 9),
            new EmployeeTask(14, 4, "Update Sales/Marketing Strategy", "Victor Norris", new DateTime(2017, 12, 13), new DateTime(2018, 4, 2), 5),
            new EmployeeTask(15, 4, "Update Sales/Revenue Report", "Mary Stern", new DateTime(2017, 12, 25), new DateTime(2018, 4, 2), 4),
            new EmployeeTask(16, 4, "Direct vs Online Sales Comparison Report", "Robin Cosworth", new DateTime(2018, 1, 2), new DateTime(2018, 3, 20), 14),
            new EmployeeTask(17, 4, "Review Sales Report and Approve Modifications", "Kelly Rodriguez", new DateTime(2017, 9, 4), new DateTime(2017, 10, 30), 8),
            new EmployeeTask(18, 4, "Update R&D Strategy", "James Anderson", new DateTime(2017, 11, 13), new DateTime(2017, 12, 4), 12),
            new EmployeeTask(19, 4, "Discuss Updated R&D Strategy", "Antony Remmen", new DateTime(2017, 10, 29), new DateTime(2017, 12, 31), 14),
            new EmployeeTask(20, 4, "Update QA Strategy", "Olivia Peyton", new DateTime(2017, 10, 31), new DateTime(2017, 11, 2), 18),
            new EmployeeTask(21, 4, "Schedule Training Events", "Taylor Riley", new DateTime(2017, 11, 19), new DateTime(2018, 4, 7), 21),
            new EmployeeTask(22, 4, "Approve Hiring of John Jeffers", "Amelia Harper", new DateTime(2018, 1, 7), new DateTime(2018, 4, 8), 10),
            new EmployeeTask(23, 0, "Increase Average Subscription Price", "Wally Hobbs", new DateTime(2017, 8, 9), new DateTime(2017, 9, 13), 96),
            new EmployeeTask(24, 23, "Update Non-Compete Agreements", "Brad Jameson", new DateTime(2017, 8, 9), new DateTime(2017, 9, 3), 96),
            new EmployeeTask(25, 23, "Update Employee Records with New NDA", "Karen Goodson", new DateTime(2017, 8, 23), new DateTime(2018, 9, 10), 100)
        };
    }
}

Program.cs

// ...
builder.Services.AddSingleton<EmployeeTaskService>();

Customize the Filter Panel

Handle the CustomizeElement event to customize filter panel appearance. Check if e.ElementType is TreeListElementType.FilterPanel to determine whether the processed element is the filter panel.

The following code snippet customizes the filter panel’s border:

Razor

@inject EmployeeTaskService EmployeeTaskService

<DxTreeList Data="TreeListData"
            KeyFieldName="Id"
            ParentKeyFieldName="ParentId"
            CustomizeElement="OnCustomizeElement"
            FilterMenuButtonDisplayMode="TreeListFilterMenuButtonDisplayMode.Always"
            FilterPanelDisplayMode="TreeListFilterPanelDisplayMode.Always">
    <Columns>
        <DxTreeListDataColumn FieldName="Name" Caption="Task" />
        <DxTreeListDataColumn FieldName="EmployeeName" Caption="Assigned To" />
        <DxTreeListDataColumn FieldName="StartDate" />
        <DxTreeListDataColumn FieldName="DueDate" />
        <DxTreeListDataColumn FieldName="Priority">
            <EditSettings>
                <DxComboBoxSettings Data="Priorities" ValueFieldName="Value" TextFieldName="Text" />
            </EditSettings>
        </DxTreeListDataColumn>
        <DxTreeListDataColumn Caption="Progress" FieldName="Status">
            <CellDisplayTemplate>
                <DxProgressBar Value="Convert.ToDouble(context.Value)" Thickness="0.875em" Size="100%"
                            MinValue="0" MaxValue="100" ShowLabel="false" />
            </CellDisplayTemplate>
        </DxTreeListDataColumn>
    </Columns>
</DxTreeList>

@code {
    List<EmployeeTask> TreeListData { get; set; }

    protected override void OnInitialized() {
        TreeListData = EmployeeTaskService.GenerateData();
    }
    void OnCustomizeElement(TreeListCustomizeElementEventArgs e) {
        if (e.ElementType == TreeListElementType.FilterPanel) {
            e.CssClass = "custom-filter-panel";
        }
    }
    record Priority(int Value, string Text);
    static readonly IReadOnlyList<Priority> Priorities = new Priority[] {
        new Priority(-1, "Low"),
        new Priority(0, "Medium"),
        new Priority(1, "High"),
    };
}

CSS

.custom-filter-panel {
    border: 2px solid #1e90ff;
    border-radius: 8px;
}

EmployeeTask.cs

public class EmployeeTask {
    public int Id { get; set; }
    public int ParentId { get; set; }
    public string Name { get; set; }
    public string EmployeeName { get; set; }
    public DateTime StartDate { get; set; }
    public DateTime DueDate { get; set; }
    public int Progress { get; set; }
    public EmployeeTask() { }
    public EmployeeTask(
        int id,
        int parentId,
        string name,
        string employeeName,
        DateTime startDate,
        DateTime dueDate,
        int progress
        )
    {
        Id = id;
        ParentId = parentId;
        Name = name;
        EmployeeName = employeeName;
        StartDate = startDate;
        DueDate = dueDate;
        Progress = progress;
    }
}

EmployeeTaskService.cs

public class EmployeeTaskService {
    public List<EmployeeTask> GenerateData() {
        return new List<EmployeeTask>() {
            new EmployeeTask(1, 0, "Simplify & Clarify Product Messaging", "John Heart", new DateTime(2018, 4, 3), new DateTime(2018, 4, 14), 14),
            new EmployeeTask(2, 1, "Prepare Financial Reports", "Samantha Bright", new DateTime(2018, 4, 3), new DateTime(2018, 4, 7), 17),
            new EmployeeTask(3, 1, "Prepare Marketing Plan", "Arthur Miller", new DateTime(2018, 4, 7), new DateTime(2018, 4, 14), 11),
            new EmployeeTask(4, 0, "Create Action Plan to Improve Customer Engagement", "Robert Reagan", new DateTime(2017, 8, 8), new DateTime(2018, 4, 8), 23),
            new EmployeeTask(5, 4, "Update Personnel Files", "Greta Sims", new DateTime(2017, 8, 8), new DateTime(2017, 10, 18), 100),
            new EmployeeTask(6, 4, "Review Health Insurance Options", "Brett Wade", new DateTime(2017, 9, 27), new DateTime(2017, 11, 10), 37),
            new EmployeeTask(7, 4, "Choose Between PPO and HMO Health Plan", "Sandra Johnson", new DateTime(2017, 12, 13), new DateTime(2018, 3, 23), 17),
            new EmployeeTask(8, 4, "Update Google Adwords Strategy", "Ed Holmes", new DateTime(2017, 8, 23), new DateTime(2017, 12, 23), 45),
            new EmployeeTask(9, 4, "Create New Brochure Design", "Barb Banks", new DateTime(2018, 1, 3), new DateTime(2018, 3, 14), 17),
            new EmployeeTask(10, 4, "Obtain Price Quote for New Brochure", "Kevin Carter", new DateTime(2018, 2, 1), new DateTime(2018, 3, 15), 18),
            new EmployeeTask(11, 4, "Brochure Design Review", "Cindy Stanwick", new DateTime(2017, 8, 22), new DateTime(2017, 10, 28), 4),
            new EmployeeTask(12, 4, "Review Website Redesign Strategy", "Sammy Hill", new DateTime(2017, 9, 16), new DateTime(2018, 3, 6), 73),
            new EmployeeTask(13, 4, "Roll Out New Website", "Davey Jones", new DateTime(2017, 11, 7), new DateTime(2018, 2, 6), 9),
            new EmployeeTask(14, 4, "Update Sales/Marketing Strategy", "Victor Norris", new DateTime(2017, 12, 13), new DateTime(2018, 4, 2), 5),
            new EmployeeTask(15, 4, "Update Sales/Revenue Report", "Mary Stern", new DateTime(2017, 12, 25), new DateTime(2018, 4, 2), 4),
            new EmployeeTask(16, 4, "Direct vs Online Sales Comparison Report", "Robin Cosworth", new DateTime(2018, 1, 2), new DateTime(2018, 3, 20), 14),
            new EmployeeTask(17, 4, "Review Sales Report and Approve Modifications", "Kelly Rodriguez", new DateTime(2017, 9, 4), new DateTime(2017, 10, 30), 8),
            new EmployeeTask(18, 4, "Update R&D Strategy", "James Anderson", new DateTime(2017, 11, 13), new DateTime(2017, 12, 4), 12),
            new EmployeeTask(19, 4, "Discuss Updated R&D Strategy", "Antony Remmen", new DateTime(2017, 10, 29), new DateTime(2017, 12, 31), 14),
            new EmployeeTask(20, 4, "Update QA Strategy", "Olivia Peyton", new DateTime(2017, 10, 31), new DateTime(2017, 11, 2), 18),
            new EmployeeTask(21, 4, "Schedule Training Events", "Taylor Riley", new DateTime(2017, 11, 19), new DateTime(2018, 4, 7), 21),
            new EmployeeTask(22, 4, "Approve Hiring of John Jeffers", "Amelia Harper", new DateTime(2018, 1, 7), new DateTime(2018, 4, 8), 10),
            new EmployeeTask(23, 0, "Increase Average Subscription Price", "Wally Hobbs", new DateTime(2017, 8, 9), new DateTime(2017, 9, 13), 96),
            new EmployeeTask(24, 23, "Update Non-Compete Agreements", "Brad Jameson", new DateTime(2017, 8, 9), new DateTime(2017, 9, 3), 96),
            new EmployeeTask(25, 23, "Update Employee Records with New NDA", "Karen Goodson", new DateTime(2017, 8, 23), new DateTime(2018, 9, 10), 100)
        };
    }
}

Program.cs

// ...
builder.Services.AddSingleton<EmployeeTaskService>();

Open the Filter Builder Dialog

The filter builder dialog is a centralized viewer/editor for the TreeList component’s filter conditions. To open this dialog, users can click the current filter criteria in the filter panel. Call the ShowFilterBuilder() method to open this dialog from code.

The following code snippet adds a toolbar button that opens the filter builder dialog:

Razor

@inject EmployeeTaskService EmployeeTaskService

<DxTreeList @ref="TreeList" Data="TreeListData" KeyFieldName="Id" ParentKeyFieldName="ParentId"
            FilterMenuButtonDisplayMode="TreeListFilterMenuButtonDisplayMode.Always"
            FilterPanelDisplayMode="TreeListFilterPanelDisplayMode.Always">
    <Columns>
        <DxTreeListDataColumn FieldName="Name" Caption="Task" />
        <DxTreeListDataColumn FieldName="EmployeeName" />
        <DxTreeListDataColumn FieldName="StartDate" />
        <DxTreeListDataColumn FieldName="DueDate" />
    </Columns>
    <ToolbarTemplate>
        <DxToolbar ItemRenderStyleMode="ToolbarRenderStyleMode.Contained">
            <Items>
                <DxToolbarItem Alignment="ToolbarItemAlignment.Right"
                               Text="Filter Builder" RenderStyle="ButtonRenderStyle.Secondary"
                               Click="() => TreeList.ShowFilterBuilder()"  />
            </Items>
        </DxToolbar>
    </ToolbarTemplate>
</DxTreeList>

@code {
    ITreeList TreeList { get; set; }
    List<EmployeeTask> TreeListData { get; set; }

    protected override void OnInitialized() {
        TreeListData = EmployeeTaskService.GenerateData();
    }
}

EmployeeTask.cs

public class EmployeeTask {
    public int Id { get; set; }
    public int ParentId { get; set; }
    public string Name { get; set; }
    public string EmployeeName { get; set; }
    public DateTime StartDate { get; set; }
    public DateTime DueDate { get; set; }
    public int Progress { get; set; }
    public EmployeeTask() { }
    public EmployeeTask(
        int id,
        int parentId,
        string name,
        string employeeName,
        DateTime startDate,
        DateTime dueDate,
        int progress
        )
    {
        Id = id;
        ParentId = parentId;
        Name = name;
        EmployeeName = employeeName;
        StartDate = startDate;
        DueDate = dueDate;
        Progress = progress;
    }
}

EmployeeTaskService.cs

public class EmployeeTaskService {
    public List<EmployeeTask> GenerateData() {
        return new List<EmployeeTask>() {
            new EmployeeTask(1, 0, "Simplify & Clarify Product Messaging", "John Heart", new DateTime(2018, 4, 3), new DateTime(2018, 4, 14), 14),
            new EmployeeTask(2, 1, "Prepare Financial Reports", "Samantha Bright", new DateTime(2018, 4, 3), new DateTime(2018, 4, 7), 17),
            new EmployeeTask(3, 1, "Prepare Marketing Plan", "Arthur Miller", new DateTime(2018, 4, 7), new DateTime(2018, 4, 14), 11),
            new EmployeeTask(4, 0, "Create Action Plan to Improve Customer Engagement", "Robert Reagan", new DateTime(2017, 8, 8), new DateTime(2018, 4, 8), 23),
            new EmployeeTask(5, 4, "Update Personnel Files", "Greta Sims", new DateTime(2017, 8, 8), new DateTime(2017, 10, 18), 100),
            new EmployeeTask(6, 4, "Review Health Insurance Options", "Brett Wade", new DateTime(2017, 9, 27), new DateTime(2017, 11, 10), 37),
            new EmployeeTask(7, 4, "Choose Between PPO and HMO Health Plan", "Sandra Johnson", new DateTime(2017, 12, 13), new DateTime(2018, 3, 23), 17),
            new EmployeeTask(8, 4, "Update Google Adwords Strategy", "Ed Holmes", new DateTime(2017, 8, 23), new DateTime(2017, 12, 23), 45),
            new EmployeeTask(9, 4, "Create New Brochure Design", "Barb Banks", new DateTime(2018, 1, 3), new DateTime(2018, 3, 14), 17),
            new EmployeeTask(10, 4, "Obtain Price Quote for New Brochure", "Kevin Carter", new DateTime(2018, 2, 1), new DateTime(2018, 3, 15), 18),
            new EmployeeTask(11, 4, "Brochure Design Review", "Cindy Stanwick", new DateTime(2017, 8, 22), new DateTime(2017, 10, 28), 4),
            new EmployeeTask(12, 4, "Review Website Redesign Strategy", "Sammy Hill", new DateTime(2017, 9, 16), new DateTime(2018, 3, 6), 73),
            new EmployeeTask(13, 4, "Roll Out New Website", "Davey Jones", new DateTime(2017, 11, 7), new DateTime(2018, 2, 6), 9),
            new EmployeeTask(14, 4, "Update Sales/Marketing Strategy", "Victor Norris", new DateTime(2017, 12, 13), new DateTime(2018, 4, 2), 5),
            new EmployeeTask(15, 4, "Update Sales/Revenue Report", "Mary Stern", new DateTime(2017, 12, 25), new DateTime(2018, 4, 2), 4),
            new EmployeeTask(16, 4, "Direct vs Online Sales Comparison Report", "Robin Cosworth", new DateTime(2018, 1, 2), new DateTime(2018, 3, 20), 14),
            new EmployeeTask(17, 4, "Review Sales Report and Approve Modifications", "Kelly Rodriguez", new DateTime(2017, 9, 4), new DateTime(2017, 10, 30), 8),
            new EmployeeTask(18, 4, "Update R&D Strategy", "James Anderson", new DateTime(2017, 11, 13), new DateTime(2017, 12, 4), 12),
            new EmployeeTask(19, 4, "Discuss Updated R&D Strategy", "Antony Remmen", new DateTime(2017, 10, 29), new DateTime(2017, 12, 31), 14),
            new EmployeeTask(20, 4, "Update QA Strategy", "Olivia Peyton", new DateTime(2017, 10, 31), new DateTime(2017, 11, 2), 18),
            new EmployeeTask(21, 4, "Schedule Training Events", "Taylor Riley", new DateTime(2017, 11, 19), new DateTime(2018, 4, 7), 21),
            new EmployeeTask(22, 4, "Approve Hiring of John Jeffers", "Amelia Harper", new DateTime(2018, 1, 7), new DateTime(2018, 4, 8), 10),
            new EmployeeTask(23, 0, "Increase Average Subscription Price", "Wally Hobbs", new DateTime(2017, 8, 9), new DateTime(2017, 9, 13), 96),
            new EmployeeTask(24, 23, "Update Non-Compete Agreements", "Brad Jameson", new DateTime(2017, 8, 9), new DateTime(2017, 9, 3), 96),
            new EmployeeTask(25, 23, "Update Employee Records with New NDA", "Karen Goodson", new DateTime(2017, 8, 23), new DateTime(2018, 9, 10), 100)
        };
    }
}

Program.cs

// ...
builder.Services.AddSingleton<EmployeeTaskService>();

Filter Builder Fields

Field Generation

The TreeList automatically generates and configures available filter builder fields based on the following column settings:

• Caption
• EditSettings
• FieldName
• Visible

The filter field hierarchy is based on the column band hierarchy. The following code snippets demonstrate how filter fields are generated based on TreeList columns:

TreeList Columns

<Columns>
    <DxTreeListDataColumn FieldName="Name" Caption="Task" />
    <DxTreeListDataColumn FieldName="EmployeeID" Caption="Assigned To" >
        <EditSettings>
            <DxComboBoxSettings Data="Employees" ValueFieldName="EmployeeID" TextFieldName="EmployeeName" />
        </EditSettings>
    </DxTreeListDataColumn>
    <DxTreeListBandColumn Caption="Timeline">
        <DxTreeListDataColumn FieldName="StartDate" />
        <DxTreeListDataColumn FieldName="DueDate" />
    </DxTreeListBandColumn>
</Columns>

EmployeeTask

public class EmployeeTask {
    public string Name { get; set; }
    public int EmployeeID { get; set; }
    public DateTime StartDate { get; set; }
    public DateTime DueDate { get; set; }
}

Autogenerated Filter Fields

<Fields>
    <DxFilterBuilderField FieldName="Name" Type="@typeof(string)" Caption="Task" />
    <DxFilterBuilderField FieldName="EmployeeID" Caption="Assigned To" Type="@typeof(int)">
        <EditSettings>
            <DxComboBoxSettings Data="Employees" ValueFieldName="EmployeeID" TextFieldName="EmployeeName" />
        </EditSettings>
    </DxFilterBuilderField>
    <DxFilterBuilderField FieldName="Timeline" Caption="Timeline" AllowSelection="false">
        <Fields>
            <DxFilterBuilderField FieldName="StartDate" Type="@typeof(DateTime)"
                                  Caption="Start Date" CaptionFullPath="Timeline.Start Date" />
            <DxFilterBuilderField FieldName="DueDate" Type="@typeof(DateTime)"
                                  Caption="Due Date" CaptionFullPath="Timeline.Due Date" />
        </Fields>
    </DxFilterBuilderField>
</Fields>

Field Visibility

The TreeList sets initial field visibility based on the corresponding column’s visibility. The filter builder dialog automatically updates field visibility once a user displays or hides a column. The dialog automatically hides filter fields generated for bands if these fields no longer contain visible children.

To always display or hide a field, set FilterBuilderFieldDisplayMode to Never/Always. The following code snippet hides the Start Date filter field:

Razor

@inject EmployeeTaskService EmployeeTaskService

<DxTreeList Data="TreeListData" KeyFieldName="Id" ParentKeyFieldName="ParentId"
            FilterMenuButtonDisplayMode="TreeListFilterMenuButtonDisplayMode.Always"
            FilterPanelDisplayMode="TreeListFilterPanelDisplayMode.Always">
    <Columns>
        <DxTreeListDataColumn FieldName="Name" Caption="Task" />
        <DxTreeListDataColumn FieldName="EmployeeName" />
        <DxTreeListDataColumn FieldName="StartDate"
                              FilterBuilderFieldDisplayMode="GridColumnFilterBuilderFieldDisplayMode.Never"/>
        <DxTreeListDataColumn FieldName="DueDate" />
    </Columns>
</DxTreeList>

@code {
    List<EmployeeTask> TreeListData { get; set; }

    protected override void OnInitialized() {
        TreeListData = EmployeeTaskService.GenerateData();
    }
}

EmployeeTask.cs

public class EmployeeTask {
    public int Id { get; set; }
    public int ParentId { get; set; }
    public string Name { get; set; }
    public string EmployeeName { get; set; }
    public DateTime StartDate { get; set; }
    public DateTime DueDate { get; set; }
    public int Progress { get; set; }
    public EmployeeTask() { }
    public EmployeeTask(
        int id,
        int parentId,
        string name,
        string employeeName,
        DateTime startDate,
        DateTime dueDate,
        int progress
        )
    {
        Id = id;
        ParentId = parentId;
        Name = name;
        EmployeeName = employeeName;
        StartDate = startDate;
        DueDate = dueDate;
        Progress = progress;
    }
}

EmployeeTaskService.cs

public class EmployeeTaskService {
    public List<EmployeeTask> GenerateData() {
        return new List<EmployeeTask>() {
            new EmployeeTask(1, 0, "Simplify & Clarify Product Messaging", "John Heart", new DateTime(2018, 4, 3), new DateTime(2018, 4, 14), 14),
            new EmployeeTask(2, 1, "Prepare Financial Reports", "Samantha Bright", new DateTime(2018, 4, 3), new DateTime(2018, 4, 7), 17),
            new EmployeeTask(3, 1, "Prepare Marketing Plan", "Arthur Miller", new DateTime(2018, 4, 7), new DateTime(2018, 4, 14), 11),
            new EmployeeTask(4, 0, "Create Action Plan to Improve Customer Engagement", "Robert Reagan", new DateTime(2017, 8, 8), new DateTime(2018, 4, 8), 23),
            new EmployeeTask(5, 4, "Update Personnel Files", "Greta Sims", new DateTime(2017, 8, 8), new DateTime(2017, 10, 18), 100),
            new EmployeeTask(6, 4, "Review Health Insurance Options", "Brett Wade", new DateTime(2017, 9, 27), new DateTime(2017, 11, 10), 37),
            new EmployeeTask(7, 4, "Choose Between PPO and HMO Health Plan", "Sandra Johnson", new DateTime(2017, 12, 13), new DateTime(2018, 3, 23), 17),
            new EmployeeTask(8, 4, "Update Google Adwords Strategy", "Ed Holmes", new DateTime(2017, 8, 23), new DateTime(2017, 12, 23), 45),
            new EmployeeTask(9, 4, "Create New Brochure Design", "Barb Banks", new DateTime(2018, 1, 3), new DateTime(2018, 3, 14), 17),
            new EmployeeTask(10, 4, "Obtain Price Quote for New Brochure", "Kevin Carter", new DateTime(2018, 2, 1), new DateTime(2018, 3, 15), 18),
            new EmployeeTask(11, 4, "Brochure Design Review", "Cindy Stanwick", new DateTime(2017, 8, 22), new DateTime(2017, 10, 28), 4),
            new EmployeeTask(12, 4, "Review Website Redesign Strategy", "Sammy Hill", new DateTime(2017, 9, 16), new DateTime(2018, 3, 6), 73),
            new EmployeeTask(13, 4, "Roll Out New Website", "Davey Jones", new DateTime(2017, 11, 7), new DateTime(2018, 2, 6), 9),
            new EmployeeTask(14, 4, "Update Sales/Marketing Strategy", "Victor Norris", new DateTime(2017, 12, 13), new DateTime(2018, 4, 2), 5),
            new EmployeeTask(15, 4, "Update Sales/Revenue Report", "Mary Stern", new DateTime(2017, 12, 25), new DateTime(2018, 4, 2), 4),
            new EmployeeTask(16, 4, "Direct vs Online Sales Comparison Report", "Robin Cosworth", new DateTime(2018, 1, 2), new DateTime(2018, 3, 20), 14),
            new EmployeeTask(17, 4, "Review Sales Report and Approve Modifications", "Kelly Rodriguez", new DateTime(2017, 9, 4), new DateTime(2017, 10, 30), 8),
            new EmployeeTask(18, 4, "Update R&D Strategy", "James Anderson", new DateTime(2017, 11, 13), new DateTime(2017, 12, 4), 12),
            new EmployeeTask(19, 4, "Discuss Updated R&D Strategy", "Antony Remmen", new DateTime(2017, 10, 29), new DateTime(2017, 12, 31), 14),
            new EmployeeTask(20, 4, "Update QA Strategy", "Olivia Peyton", new DateTime(2017, 10, 31), new DateTime(2017, 11, 2), 18),
            new EmployeeTask(21, 4, "Schedule Training Events", "Taylor Riley", new DateTime(2017, 11, 19), new DateTime(2018, 4, 7), 21),
            new EmployeeTask(22, 4, "Approve Hiring of John Jeffers", "Amelia Harper", new DateTime(2018, 1, 7), new DateTime(2018, 4, 8), 10),
            new EmployeeTask(23, 0, "Increase Average Subscription Price", "Wally Hobbs", new DateTime(2017, 8, 9), new DateTime(2017, 9, 13), 96),
            new EmployeeTask(24, 23, "Update Non-Compete Agreements", "Brad Jameson", new DateTime(2017, 8, 9), new DateTime(2017, 9, 3), 96),
            new EmployeeTask(25, 23, "Update Employee Records with New NDA", "Karen Goodson", new DateTime(2017, 8, 23), new DateTime(2018, 9, 10), 100)
        };
    }
}

Program.cs

// ...
builder.Services.AddSingleton<EmployeeTaskService>();

Filter Builder Template

Specify a FilterBuilderTemplate to apply the following customizations:

• Display custom filter fields
• Display custom content within the filter builder dialog
• Change settings of the integrated Filter Builder component

To use autogenerated fields in this template, call the context.RenderDefaultFields method within the Filter Builder component’s Fields tag.

The following code snippet customizes the filter builder dialog as follows:

• Displays the applied filter condition above the Filter Builder component
• Limits available logical operators to And and Or
• Adds a Progress filter field

Razor

@inject EmployeeTaskService EmployeeTaskService

<DxTreeList @ref="TreeList" Data="TreeListData" KeyFieldName="Id" ParentKeyFieldName="ParentId" 
            FilterPanelDisplayMode="TreeListFilterPanelDisplayMode.Always">
    <Columns>
        <DxTreeListDataColumn FieldName="Name" Caption="Task" />
        <DxTreeListDataColumn FieldName="EmployeeName" />
        <DxTreeListDataColumn FieldName="StartDate" />
        <DxTreeListDataColumn FieldName="DueDate" />
        <DxTreeListDataColumn FieldName="Priority">
            <EditSettings>
                <DxComboBoxSettings Data="Priorities" ValueFieldName="Value" TextFieldName="Text" />
            </EditSettings>
        </DxTreeListDataColumn>
    </Columns>
    <FilterBuilderTemplate>
        <b>Currently Applied Filter:</b> @(context.TreeList.GetFilterCriteria()?.ToString() ?? "No filter")
        <DxFilterBuilder @bind-FilterCriteria="context.FilterCriteria" 
            GroupOperatorTypes="[FilterBuilderGroupOperatorType.And, FilterBuilderGroupOperatorType.Or]">
            <Fields>
                @context.RenderDefaultFields()
                <DxFilterBuilderField FieldName="Status" Caption="Progress" Type="@typeof(int)">
                    <EditSettings>
                        <DxSpinEditSettings MinValue="0" MaxValue="100" />
                    </EditSettings>
                </DxFilterBuilderField>
            </Fields>
        </DxFilterBuilder>
    </FilterBuilderTemplate>
</DxTreeList>

@code {
    ITreeList TreeList { get; set; }
    List<EmployeeTask> TreeListData { get; set; }

    record Priority(int Value, string Text);
    static readonly IReadOnlyList<Priority> Priorities = new Priority[] {
        new Priority(-1, "Low"),
        new Priority(0, "Medium"),
        new Priority(1, "High"),
    };

    protected override void OnInitialized() {
        TreeListData = EmployeeTaskService.GenerateData();
    }
}

EmployeeTask.cs

    public class EmployeeTask {
    public int Id { get; set; }
    public int ParentId { get; set; }
    public string Name { get; set; }
    public string EmployeeName { get; set; }
    public DateTime StartDate { get; set; }
    public DateTime DueDate { get; set; }
    public int Priority { get; set; }
    public int Status { get; set; }
    public EmployeeTask() { }
    public EmployeeTask(
        int id,
        int parentId,
        string name,
        string employeeName,
        DateTime startDate,
        DateTime dueDate,
        int priority,
        int status
        ) {
        Id = id;
        ParentId = parentId;
        Name = name;
        EmployeeName = employeeName;
        StartDate = startDate;
        DueDate = dueDate;
        Status = status;
        Priority = priority;
    }
}

EmployeeTaskService.cs

public List<EmployeeTask> GenerateData() {
    return new List<EmployeeTask>() {
        new EmployeeTask(1, 0, "Simplify & Clarify Product Messaging", "John Heart", new DateTime(2018, 4, 3), new DateTime(2018, 4, 14), -1, 14),
        new EmployeeTask(2, 1, "Prepare Financial Reports", "Samantha Bright", new DateTime(2018, 4, 3), new DateTime(2018, 4, 7), 0, 17),
        new EmployeeTask(3, 1, "Prepare Marketing Plan", "Arthur Miller", new DateTime(2018, 4, 7), new DateTime(2018, 4, 14), 1, 11),
        new EmployeeTask(4, 0, "Create Action Plan to Improve Customer Engagement", "Robert Reagan", new DateTime(2017, 8, 8), new DateTime(2018, 4, 8), 0, 23),
        new EmployeeTask(5, 4, "Update Personnel Files", "Greta Sims", new DateTime(2017, 8, 8), new DateTime(2017, 10, 18), 0, 100),
        new EmployeeTask(6, 4, "Review Health Insurance Options", "Brett Wade", new DateTime(2017, 9, 27), new DateTime(2017, 11, 10), 1, 37),
        new EmployeeTask(7, 4, "Choose Between PPO and HMO Health Plan", "Sandra Johnson", new DateTime(2017, 12, 13), new DateTime(2018, 3, 23), -1, 17),
        new EmployeeTask(8, 4, "Update Google Adwords Strategy", "Ed Holmes", new DateTime(2017, 8, 23), new DateTime(2017, 12, 23), -1, 45),
        new EmployeeTask(9, 4, "Create New Brochure Design", "Barb Banks", new DateTime(2018, 1, 3), new DateTime(2018, 3, 14), 1, 17),
        new EmployeeTask(10, 4, "Obtain Price Quote for New Brochure", "Kevin Carter", new DateTime(2018, 2, 1), new DateTime(2018, 3, 15), 1, 18),
        new EmployeeTask(11, 4, "Brochure Design Review", "Cindy Stanwick", new DateTime(2017, 8, 22), new DateTime(2017, 10, 28), 0, 4),
        new EmployeeTask(12, 4, "Review Website Redesign Strategy", "Sammy Hill", new DateTime(2017, 9, 16), new DateTime(2018, 3, 6), -1, 73),
        new EmployeeTask(13, 4, "Roll Out New Website", "Davey Jones", new DateTime(2017, 11, 7), new DateTime(2018, 2, 6), -1, 9),
        new EmployeeTask(14, 4, "Update Sales/Marketing Strategy", "Victor Norris", new DateTime(2017, 12, 13), new DateTime(2018, 4, 2), 0, 5),
        new EmployeeTask(15, 4, "Update Sales/Revenue Report", "Mary Stern", new DateTime(2017, 12, 25), new DateTime(2018, 4, 2), 0, 4),
        new EmployeeTask(16, 4, "Direct vs Online Sales Comparison Report", "Robin Cosworth", new DateTime(2018, 1, 2), new DateTime(2018, 3, 20), -1,14),
        new EmployeeTask(17, 4, "Review Sales Report and Approve Modifications", "Kelly Rodriguez", new DateTime(2017, 9, 4), new DateTime(2017, 10, 30), 1, 8),
        new EmployeeTask(18, 4, "Update R&D Strategy", "James Anderson", new DateTime(2017, 11, 13), new DateTime(2017, 12, 4), 0, 12),
        new EmployeeTask(19, 4, "Discuss Updated R&D Strategy", "Antony Remmen", new DateTime(2017, 10, 29), new DateTime(2017, 12, 31), 0, 14),
        new EmployeeTask(20, 4, "Update QA Strategy", "Olivia Peyton", new DateTime(2017, 10, 31), new DateTime(2017, 11, 2), 1, 18),
        new EmployeeTask(21, 4, "Schedule Training Events", "Taylor Riley", new DateTime(2017, 11, 19), new DateTime(2018, 4, 7), -1, 21),
        new EmployeeTask(22, 4, "Approve Hiring of John Jeffers", "Amelia Harper", new DateTime(2018, 1, 7), new DateTime(2018, 4, 8), -1, 10),
        new EmployeeTask(23, 0, "Increase Average Subscription Price", "Wally Hobbs", new DateTime(2017, 8, 9), new DateTime(2017, 9, 13), 0, 96),
        new EmployeeTask(24, 23, "Update Non-Compete Agreements", "Brad Jameson", new DateTime(2017, 8, 9), new DateTime(2017, 9, 3), 1, 96),
        new EmployeeTask(25, 23, "Update Employee Records with New NDA", "Karen Goodson", new DateTime(2017, 8, 23), new DateTime(2018, 9, 10), 1, 100)
    };
}

Program.cs

// ...
builder.Services.AddSingleton<EmployeeTaskService>();

Filter Synchronization

The TreeList component automatically synchronizes filter changes across the following UI elements:

• Column filter menus
• Filter row
• Filter panel
• Filter builder dialog

Of these elements, only the filter panel and filter builder can display all filter conditions. Other elements have limitations, for example, column filter menus do not support the Contains operator, and filter row cells cannot display the Betweencondition. To ensure the entire filter expression is visible, add a filter panel to the TreeList. The panel also provides access to the filter builder dialog.

Note

The TreeList updates a column’s FilterRowOperatorType once users apply filters to column data using another UI element. For instance, after a user selects a filter menu value, the column’s FilterRowOperatorType switches to Equals. The operator type remains Equals even after the filter is cleared.

You can extend filter row UI and display filter operators for each column. Refer to the following example for additional information: Incorporate a selector for filter row operator type.