DxContextMenuItem.SubMenuTemplate Property

Specifies the template for the context menu item’s submenu.

Namespace: DevExpress.Blazor

Assembly: DevExpress.Blazor.v23.2.dll

NuGet Package: DevExpress.Blazor

Declaration

[Parameter]
public RenderFragment<IContextMenuItemInfo> SubMenuTemplate { get; set; }

Property Value

Type	Description
RenderFragment<IContextMenuItemInfo>	The template content.

Remarks

The Context Menu component allows you to define templates for the layout and appearance of menu items and their elements. For more information on templates for context menu items, refer to the following section: Context Menu - Item Templates.

The DxContextMenu.SubMenuTemplate property specifies the common template for submenus of all context menu items. The DxContextMenuItem.SubMenuTemplate property overrides the common submenu template for the current menu item. You can also use the SubMenuCssClass to define the appearance of Context Menu’s items.

The following example demonstrates how to define submenu templates for the Text color and Background color menu items:

Razor

<div class="demo-preventsel target-container" tabindex="0"
     @oncontextmenu="@OnContextMenu"
     @oncontextmenu:preventDefault
     @onkeydown="@OnKeyDown">
    <p style="display: inline-block; text-align: center; margin: auto; color:@TextColor; background-color:@BackgroundColor">Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris sit amet metus vel nisi blandit tincidunt vel efficitur purus. Nunc nec turpis tempus, accumsan orci auctor, imperdiet mauris. Fusce id purus magna.</p>
</div>

<DxContextMenu @ref="@ContextMenu" PositionTarget="#section-Templates .target-container" SizeMode="Params.SizeMode">
    <Items>
        <DxContextMenuItem Text="Text color">
            <SubMenuTemplate>
                <ColorPicker HeaderText="Text color" SelectedColor="@TextColor" ColorChanged="ChangeTextColor"/>
            </SubMenuTemplate>
        </DxContextMenuItem>
        <DxContextMenuItem Text="Background color">
            <SubMenuTemplate>
                <ColorPicker HeaderText="Background color" SelectedColor="@BackgroundColor" ColorChanged="@ChangeBackgroundColor"/>
            </SubMenuTemplate>
        </DxContextMenuItem>
        <DxContextMenuItem Text="Reset colors" Click="@ResetColors" BeginGroup="true"
                           Enabled="@(BackgroundColor != UnsetValue || TextColor != UnsetValue)"/>
    </Items>
</DxContextMenu>

@code {
    const string UnsetValue = "unset";
    DxContextMenu ContextMenu { get; set; }
    private string TextColor { get; set; } = UnsetValue;
    private string BackgroundColor { get; set; } = UnsetValue;

    void ChangeTextColor(string color) {
        TextColor = color;
        ContextMenu.HideAsync();
    }
    void ChangeBackgroundColor(string color) {
        BackgroundColor = color;
        ContextMenu.HideAsync();
    }
    void ResetColors() {
        BackgroundColor = TextColor = UnsetValue;
        InvokeAsync(StateHasChanged);
    }
    async void OnContextMenu(MouseEventArgs args) {
        await ContextMenu.ShowAsync(args);
    }
    async void OnKeyDown(KeyboardEventArgs args) {
        if (args.Key == "F10" && args.ShiftKey)
            await ContextMenu.ShowAsync(ContextMenuPosition.Center);
    }
}

ColorPicker.razor

<div>
    <ul class="list-unstyled m-0">
        <li>
            <div class="color-picker-item">@HeaderText</div>
        </li>
        <li role="separator" class="color-picker-separator"></li>
        <li>
            <div class="color-picker-item color-picker-container">
                @foreach(var color in colors) {
                    <div class="color-picker-cell @CssClassSelectedCell(color)" style="background-color:@color" tabindex="0"
                        @onkeypress="(e) => HandleActionKeys(e.Code, () => ChangeColor(color))"
                        @onclick="() => ChangeColor(color)"></div>
                }
            </div>
        </li>
        <li role="separator" class="color-picker-separator"></li>
        <li>
            <div class="color-picker-item color-picker-item-reset" @onclick="ResetColor"
                @onkeypress="(e) => HandleActionKeys(e.Code, ResetColor)">
                <div class="color-picker-cell" tabindex="0"></div>
                <div tabindex="0">No color</div>
            </div>
        </li>
    </ul>
</div>

@code {
    static readonly string[] colors = new[] {
        "#000000",
        "#c0c0c0",
        "#808080",
        "#808000",
        "#800000",
        "#800080",
        "#008000",
        "#008080",
        "#000080",
        "#ff0000",
        "#0000ff",
        "#ff00ff",
        "#00ffff",
        "#00ff00",
        "#ffff00"
    };

    void ChangeColor(string color) {
        SelectedColor = color;
        ColorChanged.InvokeAsync(color);
    }

    void ResetColor() {
        SelectedColor = "unset";
        ColorChanged.InvokeAsync("unset");
    }

    void HandleActionKeys(string key, Action handler) {
        if (key == "Enter" || key == "Space")
            handler();
    }

    string CssClassSelectedCell(string color) =>
        color == SelectedColor ? "selected" : "";

    [Parameter] public string HeaderText { get; set; }
    [Parameter] public EventCallback<string> ColorChanged { get; set; }
    [Parameter] public string SelectedColor { get; set; }
}

ColorPicker.razor.css

/*BeginHide*/::deep /*EndHide*/ .dropdown-divider {
    margin: unset !important;
}

.color-picker-item {
    margin: 0.3125rem 0.5rem;
    font-size: 0.875rem;
    line-height: 1.4285;
}

.color-picker-container {
    display: flex;
    flex-wrap: wrap;
    min-width: 10rem;
    cursor: pointer;
    justify-content: space-between;
}

.color-picker-cell {
    height: 1.75rem;
    width: 1.75rem;
    cursor: pointer;
    margin: 0.1rem 0.1rem 0.1rem 0.1rem;
    border: 1px solid var(--bs-primary);
}

.color-picker-item-reset {
    display: flex;
    align-items: center;
    justify-content: flex-start;
}

.color-picker-item-reset > .color-picker-cell {
    height: 1rem;
    width: 1rem;
    margin-right: 0.5rem;
}

.color-picker-container > .color-picker-cell:hover,
.color-picker-item-reset:hover > .color-picker-cell {
    border: 2px solid var(--bs-primary);
}

.color-picker-container > .color-picker-cell.selected {
    border: 2px solid var(--bs-primary);
}

.color-picker-separator {
    height: 0;
    overflow: hidden;
    border-top: 1px solid;
    opacity: 0.3;
}

Run Demo: Context Menu - Templates