Blazor Tree Grid Search Filter

    The Ignite UI for Blazor Search Filter feature in Blazor Tree Grid enables the process of finding values in the collection of data. We make it easier to set up this functionality and it can be implemented with a search input box, buttons, keyboard navigation and other useful features for an even better user experience. While browsers natively provide content search functionality, most of the time the IgbTreeGrid virtualizes its columns and rows that are out of view. In these cases, the native browser search is unable to search data in the virtualized cells, since they are not part of the DOM. We have extended the Blazor Material table-based grid with a search API that allows you to search through the virtualized content of the IgbTreeGrid.

    Blazor Search Example

    The following example represents IgbTreeGrid with search input box that allows searching in all columns and rows, as well as specific filtering options for each column.

    Blazor Search Usage

    Tree Grid Setup

    Let's start by creating our grid and binding it to our data. We will also add some custom styles for the components we will be using!

    <IgbTreeGrid @ref=treeGrid AutoGenerate=false Data=EmployeesFlatData PrimaryKey="ID" ForeignKey="ParentID" AllowFiltering=true Height="100%" Width="100%">
    <IgbColumn Field="Name" DataType="GridColumnDataType.String" Sortable=true></IgbColumn>
    <IgbColumn Field="ID" DataType="GridColumnDataType.Number" Sortable=true></IgbColumn>
    <IgbColumn Field="Title" DataType="GridColumnDataType.String" Sortable=true></IgbColumn>
    <IgbColumn Field="Age" DataType="GridColumnDataType.Number" Sortable=true></IgbColumn>
    <IgbColumn Field="HireDate" DataType="GridColumnDataType.Date" Sortable=true></IgbColumn>
</IgbTreeGrid>

    Great, and now let's prepare for the search API of our IgbTreeGrid! We can create a few properties, which can be used for storing the currently searched text and whether the search is case sensitive and/or by an exact match.

    private IgbTreeGrid treeGrid;

public string searchText = "";
public bool caseSensitive = false;
public bool exactMatch = false;

    Blazor Search Box Input

    Now let's create our search input! By binding our SearchText to the Value property to our newly created input and subscribe to the ValueChanging event, we can detect every single SearchText modification by the user. This will allow us to use the IgbTreeGrid's FindNext and FindPrev methods to highlight all the occurrences of the SearchText and scroll to the next/previous one (depending on which method we have invoked).

    Both the FindNext and the FindPrev methods have three arguments:

    • Text: string (the text we are searching for)
    • (optional) CaseSensitive: boolean (should the search be case sensitive or not, default value is false)
    • (optional) ExactMatch: boolean (should the search be by an exact match or not, default value is false)

    When searching by an exact match, the search API will highlight as results only the cell values that match entirely the SearchText by taking the case sensitivity into account as well. For example the strings 'software' and 'Software' are an exact match with a disregard for the case sensitivity.

    The methods from above return a number value (the number of times the IgbTreeGrid contains the given string).

    <IgbInput ValueChanging="OnValueChanging" Value="@searchText" />

public void NextSearch()
{
    this.treeGrid.FindNext(this.searchText, this.caseSensitive, this.exactMatch);
}

    Add Search Buttons

    In order to freely search and navigate among our search results, let's create a couple of buttons by invoking the FindNext and the FindPrev methods inside the buttons' respective click event handlers.

    <IgbIconButton Variant="IconButtonVariant.Flat" @onclick="PrevSearch">
    <IgbIcon IconName="prev" Collection="material"/>
</IgbIconButton>
<IgbIconButton Variant="IconButtonVariant.Flat" @onclick="NextSearch">
    <IgbIcon IconName="next" Collection="material" />
</IgbIconButton>

@code {
    private IgbTreeGrid treeGrid;

    public void PrevSearch()
    {
        this.treeGrid.FindPrevAsync(this.searchText, this.caseSensitive, this.exactMatch);
    }

    public void NextSearch()
    {
        this.treeGrid.FindNextAsync(this.searchText, this.caseSensitive, this.exactMatch);
    }
}

    We can also allow the users to navigate the results by using the keyboard's arrow keys and the Enter key. In order to achieve this, we can handle the keydown event of our search input by preventing the default caret movement of the input with the PreventDefault method and invoke the FindNext/FindPrev methods depending on which key the user has pressed.

    <IgbInput ValueChanging="OnValueChanging" Value="@searchText" @onkeydown="OnSearchKeyDown" />

@code {
    private void OnSearchKeyDown(KeyboardEventArgs evt)
    {
        if (evt.Key == "Enter" || evt.Key == "ArrowDown") {
            this.treeGrid.FindNextAsync(this.searchText, this.caseSensitive, this.exactMatch);
        } else if (evt.Key == "ArrowUp") {
            this.treeGrid.FindPrevAsync(this.searchText, this.caseSensitive, this.exactMatch);
        }
    }

    public void OnValueChanging(string newValue)
    {
        this.searchText = newValue;
        this.treeGrid.FindNextAsync(this.searchText, this.caseSensitive, this.exactMatch);
    }
}

    Case Sensitive and Exact Match

    Now let's allow the user to choose whether the search should be case sensitive and/or by an exact match. For this purpose we can use simple selectable Chips and bind to the SelectedChanged event to determine when the user interacts with them.

    <IgbChip Selectable=true SelectedChanged="UpdateCase">
    Case Sensitive
</IgbChip>
<IgbChip  Selectable=true SelectedChanged="UpdateExactSearch">
    Exact Match
</IgbChip>

@code {
    public void UpdateCase(bool selected) {
        this.caseSensitive = selected;
        this.grid.FindNextAsync(this.searchText, this.caseSensitive, this.exactMatch);
    }

    public void UpdateExactSearch(bool selected) {
        this.exactMatch = selected;
        this.grid.FindNextAsync(this.searchText, this.caseSensitive, this.exactMatch);
    }
}

    Persistence

    What if we would like to filter and sort our IgbTreeGrid or even to add and remove records? After such operations, the highlights of our current search automatically update and persist over any text that matches the SearchText! Furthermore, the search will work with paging and will persist the highlights through changes of the IgbTreeGrid's PerPage property.

    Adding icons

    By using some of our other components, we can create an enriched user interface and improve the overall design of our entire search bar! We can have a nice search or delete icon on the left of the search input, a couple of chips for our search options and some material design icons combined with nice ripple styled buttons for our navigation on the right. We can wrap these components inside an input group for a more refined design.

    To do this, let's go and grab the IgbInput, IgbIcon, IgbIconButton and the IgbChip modules.

    // eg. Program.cs register the following:
builder.Services.AddIgniteUIBlazor(
    typeof(IgbTreeGridModule),
    typeof(IgbInputModule),
    typeof(IgbIconButtonModule),
    typeof(IgbIconModule)
);

    @code {
    private IgbIcon searchIconRef { get; set; }
    const string searchIcon = "<svg width='24' height='24' viewBox='0 0 24 24'><path d='M15.5 14h-.79l-.28-.27C15.41 12.59 16 11.11 16 9.5 16 5.91 13.09 3 9.5 3S3 5.91 3 9.5 5.91 16 9.5 16c1.61 0 3.09-.59 4.23-1.57l.27.28v.79l5 4.99L20.49 19l-4.99-5zm-6 0C7.01 14 5 11.99 5 9.5S7.01 5 9.5 5 14 7.01 14 9.5 11.99 14 9.5 14z' /></svg>";
    const string prevIcon = "<svg width='24' height='24' viewBox='0 0 24 24'><path d='M15.41 7.41 14 6l-6 6 6 6 1.41-1.41L10.83 12z'></path></svg>";
    const string nextIcon = "<svg width='24' height='24' viewBox='0 0 24 24'><path d='M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z'></path></svg>";
    const string clearIcon = "<svg width='24' height='24' viewBox='0 0 24 24' title='Clear'><path d='M19 6.41 17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12z'></path></svg>";
    
    protected override void OnAfterRender(bool firstRender)
    {
        if (this.searchIconRef != null && firstRender)
        {
            this.searchIconRef.EnsureReady().ContinueWith(new Action<Task>((e) =>
            {
                this.searchIconRef.RegisterIconFromTextAsync("search", searchIcon, "material");
                this.searchIconRef.RegisterIconFromTextAsync("prev", prevIcon, "material");
                this.searchIconRef.RegisterIconFromTextAsync("next", nextIcon, "material");
                this.searchIconRef.RegisterIconFromTextAsync("clear", clearIcon, "material");
            }));
        }
    }
}

    Finally, let's update our template with the new components!

    <IgbInput ValueChanging="OnValueChanging" Value="@searchText" @onkeydown="OnSearchKeyDown">
    @if (searchText.Length == 0)
    {
        <IgbIcon @ref="searchIconRef" slot="prefix" IconName="search" Collection="material"/>
    }
    @if (searchText.Length > 0)
    {
        <IgbIcon slot="prefix" IconName="clear" Collection="material" @onclick="ClearSearch"/>
    }

    <div class="chips" slot="suffix">
        <IgbChip Selectable=true SelectedChanged="UpdateCase">
            Case Sensitive
        </IgbChip>
        <IgbChip  Selectable=true SelectedChanged="UpdateExactSearch">
            Exact Match
        </IgbChip>
    </div>
    <div class="searchButtons" slot="suffix">
        <IgbIconButton Variant="IconButtonVariant.Flat" @onclick="PrevSearch">
            <IgbIcon IconName="prev" Collection="material"/>
        </IgbIconButton>
        <IgbIconButton Variant="IconButtonVariant.Flat" @onclick="NextSearch">
            <IgbIcon IconName="next" Collection="material" />
        </IgbIconButton>
    </div>
</IgbInput>

@code {

    public void clearSearch()
    {
        this.searchText = "";
        this.grid.ClearSearchAsync();
    }
}

    On the right in our input group, let's create three separate containers with the following purposes:

    • For displaying a couple of chips that toggle the CaseSensitive and the ExactMatch properties. We have replaced the checkboxes with two stylish chips that change color based on these properties. Whenever a chip is clicked, we invoke its respective handler.
        <div class="chips" slot="suffix">
        <IgbChip Selectable=true SelectedChanged="UpdateCase">
            Case Sensitive
        </IgbChip>
        <IgbChip  Selectable=true SelectedChanged="UpdateExactSearch">
            Exact Match
        </IgbChip>
    </div>

@code {
    public void UpdateCase(bool selected) {
        this.caseSensitive = selected;
        this.grid.FindNextAsync(this.searchText, this.caseSensitive, this.exactMatch);
    }

    public void UpdateExactSearch(bool selected) {
        this.exactMatch = selected;
        this.grid.FindNextAsync(this.searchText, this.caseSensitive, this.exactMatch);
    }
}
    • For the search navigation buttons, we have transformed our inputs into ripple styled buttons with material icons. The handlers for the click events remain the same - invoking the FindNext/FindPrev methods.
    <div class="searchButtons" slot="suffix">
    <IgbIconButton Variant="IconButtonVariant.Flat" @onclick="PrevSearch">
        <IgbIcon IconName="prev" Collection="material"/>
    </IgbIconButton>
    <IgbIconButton Variant="IconButtonVariant.Flat" @onclick="NextSearch">
        <IgbIcon IconName="next" Collection="material" />
    </IgbIconButton>
</div>
@code {
    public void PrevSearch()
    {
        this.grid.FindPrevAsync(this.searchText, this.caseSensitive, this.exactMatch);
    }

    public void NextSearch()
    {
        this.grid.FindNextAsync(this.searchText, this.caseSensitive, this.exactMatch);
    }
}

    Known Limitations

    Limitation Description
    Searching in cells with a template The search functionality highlights work only for the default cell templates. If you have a column with custom cell template, the highlights will not work so you should either use alternative approaches, such as a column formatter, or set the Searchable property on the column to false.
    Remote Virtualization The search will not work properly when using remote virtualization
    Cells with cut off text When the text in the cell is too large to fit and the text we are looking for is cut off by the ellipsis, we will still scroll to the cell and include it in the match count, but nothing will be highlighted

    API References

    In this article we implemented our own search bar for the IgbTreeGrid with some additional functionality when it comes to navigating between the search results. We also used some additional Ignite UI for Blazor components like icons, chips and inputs. The search API is listed below.

    IgbTreeGrid methods:

    IgbColumn properties:

    Additional components with relative APIs that were used:

    Additional Resources

    Our community is active and always welcoming to new ideas.