Bootstrap Blazor enterprise-level UI component library

Select drop-down selection box

Drop-down selection boxes are available in a variety of colors

Demo

In this example, the first drop-down box does not have a Value bidirectional binding, so you only change when you select different options, and the remaining drop-down boxes share the same data source Items and bind Value values in both directions, changing together when you select different options

3/22/2023 4:43:03 PM +08:00: SelectedItem Text: 上海 Value: Shanghai Selected

<div class="row g-3">
    <div class="col-12 col-sm-6">
        <Select Items="Items" OnSelectedItemChanged="OnItemChanged" @bind-Value="Model.Name"></Select>
    </div>
    <div class="col-12 col-sm-6">
        <Select Color="Color.Primary" Items="Items" OnSelectedItemChanged="OnItemChanged" @bind-Value="Model.Name"></Select>
    </div>
    <div class="col-12 col-sm-6">
        <Select Color="Color.Success" Items="Items" OnSelectedItemChanged="OnItemChanged" @bind-Value="Model.Name"></Select>
    </div>
    <div class="col-12 col-sm-6">
        <Select Color="Color.Danger" Items="Items" OnSelectedItemChanged="OnItemChanged" @bind-Value="Model.Name"></Select>
    </div>
    <div class="col-12 col-sm-6">
        <Select Color="Color.Warning" Items="Items" OnSelectedItemChanged="OnItemChanged" @bind-Value="Model.Name"></Select>
    </div>
    <div class="col-12 col-sm-6">
        <Select Color="Color.Info" Items="Items" OnSelectedItemChanged="OnItemChanged" @bind-Value="Model.Name"></Select>
    </div>
    <div class="col-12 col-sm-6">
        <Select Color="Color.Secondary" Items="Items" OnSelectedItemChanged="OnItemChanged" @bind-Value="Model.Name"></Select>
    </div>
    <div class="col-12 col-sm-6">
        <Select Color="Color.Dark" Items="Items" OnSelectedItemChanged="OnItemChanged" @bind-Value="Model.Name"></Select>
    </div>
</div>
<BlockLogger @ref="Trace" class="mt-3" />

@code {
    private BlockLogger? Trace { get; set; }

    private Foo Model { get; set; } = new Foo();

    private IEnumerable<SelectedItem> Items { get; set; } = new[]
    {
        new SelectedItem ("Beijing", "北京"),
        new SelectedItem ("Shanghai", "上海") { Active = true },
    };

    private Task OnItemChanged(SelectedItem item)
    {
        Trace?.Log($"SelectedItem Text: {item.Text} Value: {item.Value} Selected");
        StateHasChanged();
        return Task.CompletedTask;
    }
}

Select disables the drop-down box

Selector unavailable state

Demo

The options in the drop-down box disable the example

@using BootstrapBlazor.Shared.Samples;
@inject IStringLocalizer<Selects> Localizer

<div class="row g-3">
    <div class="col-12 col-sm-6">
        <Select TValue="string" Color="Color.Primary" Items="Items" IsDisabled="true"></Select>
    </div>
    <div class="col-12 col-sm-6">
        <Select TValue="string" Color="Color.Success" Items="Items" IsDisabled="true"></Select>
    </div>
    <div class="col-12 col-sm-6">
        <Select TValue="string" Color="Color.Danger" Items="Items" IsDisabled="true"></Select>
    </div>
    <div class="col-12 col-sm-6">
        <Select TValue="string" Color="Color.Warning" Items="Items" IsDisabled="true"></Select>
    </div>
    <div class="col-12 col-sm-6">
        <Select TValue="string" Color="Color.Info" Items="Items" IsDisabled="true"></Select>
    </div>
    <div class="col-12 col-sm-6">
        <Select TValue="string" Color="Color.Secondary" Items="Items" IsDisabled="true"></Select>
    </div>
    <div class="col-12 col-sm-6">
        <Select TValue="string" Color="Color.Dark" Items="Items" IsDisabled="true"></Select>
    </div>
</div>
<p class="mt-3">@((MarkupString)Localizer["SelectsDisableOption"].Value)</p>
<div class="row">
    <div class="col-12 col-sm-6">
        <Select TValue="string" Items="Items4" />
    </div>
</div>

@code {
    private IEnumerable<SelectedItem> Items { get; set; } = new[]
    {
        new SelectedItem ("Beijing", "北京"),
        new SelectedItem ("Shanghai", "上海") { Active = true },
    };

    private readonly IEnumerable<SelectedItem> Items4 = new[]
    {
        new SelectedItem ("Beijing", "北京") { IsDisabled = true},
        new SelectedItem ("Shanghai", "上海") { Active = true },
        new SelectedItem ("Guangzhou", "广州")
    };
}

Select two-way binding

The values in the text box change as you change the drop-down option by binding the Model.Name property to the component with Select .

Demo

<div class="row g-3">
    <div class="col-12 col-sm-6">
        <Select Color="Color.Primary" Items="Items" @bind-Value="Model.Name"></Select>
    </div>
    <div class="col-12 col-sm-6">
        <BootstrapInput readonly @bind-Value="Model.Name" />
    </div>
</div>

@code {
    private Foo Model { get; set; } = new Foo();

    private IEnumerable<SelectedItem> Items { get; set; } = new[]
    {
        new SelectedItem ("Beijing", "北京"),
        new SelectedItem ("Shanghai", "上海") { Active = true },
    };
}

Select cascading binding

The second drop-down box dynamically populates the content by selecting the different options for the first drop-down box.

Demo

@using BootstrapBlazor.Shared.Samples;
@inject IStringLocalizer<Selects> Localizer
@inject DialogService Dialog

<div class="row g-3">
    <div class="col-12 col-sm-6">
        <Select TValue="string" Items="Items3" OnSelectedItemChanged="OnCascadeBindSelectClick" />
    </div>
    <div class="col-12 col-sm-6">
        <Select TValue="string" Items="Items2" />
    </div>
    <div class="col-12">
        <Button Text="@Localizer["SelectsCascadingButtonText1"]" OnClickWithoutRender="OnShowDialog" />
    </div>
</div>

@code {
    private readonly IEnumerable<SelectedItem> Items3 = new SelectedItem[]
    {
        new SelectedItem ("", "请选择 ..."),
        new SelectedItem ("Beijing", "北京") { Active = true },
        new SelectedItem ("Shanghai", "上海"),
        new SelectedItem ("Hangzhou", "杭州")
    };

    private IEnumerable<SelectedItem>? Items2 { get; set; }

    private Task OnShowDialog() => Dialog.Show(new DialogOption()
    {
        Title = "弹窗中使用级联下拉框",
        Component = BootstrapDynamicComponent.CreateComponent<CustomerSelectDialog>()
    });

    private async Task OnCascadeBindSelectClick(SelectedItem item)
    {
        // 模拟异步通讯切换线程
        await Task.Delay(10);
        if (item.Value == "Beijing")
        {
            Items2 = new SelectedItem[]
            {
                new SelectedItem("1","朝阳区") { Active = true},
                new SelectedItem("2","海淀区"),
            };
        }
        else if (item.Value == "Shanghai")
        {
            Items2 = new SelectedItem[]
            {
                new SelectedItem("1","静安区"),
                new SelectedItem("2","黄浦区") { Active = true } ,
            };
        }
        else
        {
            Items2 = Enumerable.Empty<SelectedItem>();
        }
        StateHasChanged();
    }
}

Select client validation

When the drop-down box is not selected, it is blocked when the submit button is clicked.

Demo

@using BootstrapBlazor.Shared.Samples;
@inject IStringLocalizer<Selects> Localizer

<ValidateForm Model="BindModel">
    <div class="row g-3">
        <div class="col-12 col-sm-6">
            <Select @bind-Value="BindModel.Name">
                <Options>
                    <SelectOption Text="@Localizer["SelectsOption1"]" Value="" />
                    <SelectOption Text="@Localizer["SelectsOption2"]" Value="1" />
                    <SelectOption Text="@Localizer["SelectsOption3"]" Value="2" />
                    <SelectOption Text="@Localizer["SelectsOption4"]" Value="3" />
                </Options>
            </Select>
        </div>
        <div class="col-12 col-sm-6 align-self-end">
            <Button ButtonType="ButtonType.Submit">@Localizer["SelectsClientValidationButtonText2"]</Button>
        </div>
    </div>
</ValidateForm>

@code {
    private Foo BindModel { get; set; } = new Foo() { Name = "" };
}

Grouping

Alternatives are presented in groups

Demo

<div class="row">
    <div class="col-12 col-sm-6">
        <Select TValue="string" Color="Color.Primary" Items="GroupItems">
        </Select>
    </div>
</div>

@code {
    private readonly IEnumerable<SelectedItem> GroupItems = new SelectedItem[]
    {
        new SelectedItem ("Jilin", "吉林") { GroupName = "东北"},
        new SelectedItem ("Liaoning", "辽宁") {GroupName = "东北", Active = true },
        new SelectedItem ("Beijing", "北京") { GroupName = "华中"},
        new SelectedItem ("Shijiazhuang", "石家庄") { GroupName = "华中"},
        new SelectedItem ("Shanghai", "上海") {GroupName = "华东", Active = true },
        new SelectedItem ("Ningbo", "宁波") {GroupName = "华东", Active = true }
    };
}

The binding generic is the Guid structure

The component binding value is an example of a Guid structure

Demo

362e4798-deba-442e-b05a-70ced8ee59eb

<div class="row g-3">
    <div class="col-12 col-sm-6">
        <Select Color="Color.Primary" Items="GuidItems" @bind-Value="CurrentGuid" />
    </div>
    <div class="col-12 col-sm-6">
        <div class="form-control">@CurrentGuid</div>
    </div>
</div>

@code {
    private Guid CurrentGuid { get; set; }

    private readonly IEnumerable<SelectedItem> GuidItems = new SelectedItem[]
    {
        new SelectedItem(Guid.NewGuid().ToString(), "Guid1"),
        new SelectedItem(Guid.NewGuid().ToString(), "Guid2")
    };
}

The label is displayed

When a component binds in both directions, it automatically determines whether label text is displayed based on the conditions

Demo

The pre-label explicit rules are consistent with the BootstrapInput component of the of the [The portal]

Bidirectional binding displays labels

Bidirectional bindings show that bidirectional bindings do not display labels

Customize DisplayText

Custom city

@using BootstrapBlazor.Shared.Samples;
@inject IStringLocalizer<Selects> Localizer

<Divider Text="@Localizer["SelectsDispalyLabelDivider1"]" Alignment="Alignment.Left" style="margin: 2rem 0;"></Divider>
<ValidateForm Model="Model">
    <div class="row">
        <div class="col-12">
            <Select Color="Color.Primary" Items="Items" @bind-Value="Model.Name" />
        </div>
    </div>
</ValidateForm>
<Divider Text="@Localizer["SelectsDispalyLabelDivider2"]" Alignment="Alignment.Left" style="margin: 2rem 0;" />
<div class="row">
    <div class="col-12">
        <Select Color="Color.Primary" Items="Items" @bind-Value="Model.Name" />
    </div>
</div>
<Divider Text="@Localizer["SelectsDispalyLabelDivider3"]" Alignment="Alignment.Left" style="margin: 2rem 0;"></Divider>
<div class="row">
    <div class="col-12">
        <Select Color="Color.Primary" Items="Items" @bind-Value="Model.Name" DisplayText="@Localizer["SelectsDispalyLabelSelectText"]" ShowLabel="true" />
    </div>
</div>

@code {
    private Foo Model { get; set; } = new Foo();

    private IEnumerable<SelectedItem> Items { get; set; } = new[]
    {
        new SelectedItem ("Beijing", "北京"),
        new SelectedItem ("Shanghai", "上海") { Active = true },
    };
}

Static data

Hard-coded writing directly inside the Select component is suitable for static data drop-down boxes

Demo

@using BootstrapBlazor.Shared.Samples;
@inject IStringLocalizer<Selects> Localizer

<div class="row">
    <div class="col-12 col-sm-6">
        <Select TValue="string">
            <Options>
                <SelectOption Text="@Localizer["SelectsOption1"]" Value="1" />
                <SelectOption Text="@Localizer["SelectsOption2"]" Value="2" Active="true" />
                <SelectOption Text="@Localizer["SelectsOption3"]" Value="3" />
            </Options>
        </Select>
    </div>
</div>

Enumerate the data

an example of a type enumerated a select component binding

Demo

Enumeration When the binding value is an empty enumeration type, the component automatically adds preferences internally through the PlaceHolder value, and when the PlaceHolder value is not set, please select ... as a preference, and this example binds the EnumEducation enumeration type data

Setting PalceHolder is not valid when the binding value is an enumerated type

Can be empty

Not empty

Primary

@using BootstrapBlazor.Shared.Samples;
@inject IStringLocalizer<Selects> Localizer

<div class="row g-3">
    <div class="col-12 col-sm-6">
        <Select @bind-Value="SelectedEnumItem1" PlaceHolder="@Localizer["SelectsPlaceHolder"]" ShowLabel="true" DisplayText="@Localizer["SelectsEnumSelectText1"]">
        </Select>
    </div>
    <div class="col-12 col-sm-6">
        <Select @bind-Value="SelectedEnumItem1" ShowLabel="true" DisplayText="@Localizer["SelectsEnumSelectText1"]">
        </Select>
    </div>
    <div class="col-12 col-sm-6">
        <Select @bind-Value="SelectedEnumItem" ShowLabel="true" DisplayText="@Localizer["SelectsEnumSelectText2"]">
        </Select>
    </div>
    <div class="col-12 col-sm-6 align-self-end">
        <div class="form-control">@SelectedEnumItem</div>
    </div>
</div>

@code {
    private EnumEducation SelectedEnumItem { get; set; } = EnumEducation.Primary;

    private EnumEducation? SelectedEnumItem1 { get; set; }
}

The binding can be an empty type

an example of the Select component binding int? type

Demo

When the first option is selected, the binding value SelectIntItem to null

null

<div class="row g-3">
    <div class="col-12 col-sm-6">
        <Select Items="NullableIntItems" @bind-Value="SelectedIntItem">
        </Select>
    </div>
    <div class="col-12 col-sm-6">
        <div class="form-control">@GetSelectedIntItemString()</div>
    </div>
</div>

@code {
    private int? SelectedIntItem { get; set; }

    private string GetSelectedIntItemString()
    {
        return SelectedIntItem.HasValue ? SelectedIntItem.Value.ToString() : "null";
    }

    private IEnumerable<SelectedItem> NullableIntItems { get; set; } = new SelectedItem[]
    {
        new SelectedItem() { Text = "Item 1", Value = "" },
        new SelectedItem() { Text = "Item 2", Value = "2" },
        new SelectedItem() { Text = "Item 3", Value = "3" }
    };
}

The binding can be an empty Boolean type

an example of the bool? type of select component binding

Demo

Can be used for the empty boolean type more than in the conditional search box

When the first option is selected, the binding value SelectIntItem to null

null

<div class="row g-3">
    <div class="col-12 col-sm-6">
        <Select Items="NullableBoolItems" @bind-Value="SelectedBoolItem">
        </Select>
    </div>
    <div class="col-12 col-sm-6">
        <div class="form-control">@GetSelectedBoolItemString()</div>
    </div>
</div>

@code {
    private bool? SelectedBoolItem { get; set; }

    private string GetSelectedBoolItemString()
    {
        return SelectedBoolItem.HasValue ? SelectedBoolItem.Value.ToString() : "null";
    }

    private IEnumerable<SelectedItem> NullableBoolItems { get; set; } = new SelectedItem[]
    {
        new SelectedItem() { Text = "空值", Value = "" },
        new SelectedItem() { Text = "True 值", Value = "true" },
        new SelectedItem() { Text = "False 值", Value = "false" }
    };
}

Custom option templates

By setting the ItemTemplate you can customize the option rendering style

Demo

<div class="row">
    <div class="col-12 col-sm-6">
        <Select TValue="string" Items="Items">
            <ItemTemplate>
                <div class="dropdown-item-demo">
                    <i class="fa-solid fa-font-awesome"></i>
                    <span>@context.Text</span>
                    <i class="fa-solid fa-star"></i>
                </div>
            </ItemTemplate>
        </Select>
    </div>
</div>

@code {
    private IEnumerable<SelectedItem> Items { get; set; } = new[]
    {
        new SelectedItem ("Beijing", "北京"),
        new SelectedItem ("Shanghai", "上海") { Active = true },
    };
}

Drop-down box with search box

Controls whether the search box is displayed by setting the ShowSearch property, which is not displayed by default false

Demo

<div class="row g-3">
    <div class="col-12 col-sm-6">
        <Select TValue="string" Items="Items" ShowSearch="true" />
    </div>
    <div class="col-12 col-sm-6">
        <Select TValue="string" Items="StringItems" ShowSearch="true" />
    </div>
</div>

@code {
    private IEnumerable<SelectedItem> Items { get; set; } = new[]
    {
        new SelectedItem ("Beijing", "北京"),
        new SelectedItem ("Shanghai", "上海") { Active = true },
    };

    private readonly IEnumerable<SelectedItem> StringItems = new[]
    {
        new SelectedItem ("1", "1"),
        new SelectedItem ("12", "12"),
        new SelectedItem ("123", "123"),
        new SelectedItem ("1234", "1234"),
        new SelectedItem ("a", "a"),
        new SelectedItem ("ab", "ab"),
        new SelectedItem ("abc", "abc"),
        new SelectedItem ("abcd", "abcd"),
        new SelectedItem ("abcde", "abcde")
    };
}

Drop-down box with confirmation

Block changes to the current value by setting the OnBeforeSelectedItemChange delegate.

Demo

@using BootstrapBlazor.Shared.Samples;
@inject IStringLocalizer<Selects> Localizer

<div class="row">
    <div class="col-12 col-sm-6">
        <Select TValue="string" Items="Items" OnBeforeSelectedItemChange="@OnBeforeSelectedItemChange"
                SwalTitle="@Localizer["SwalTitle"]" SwalContent="@Localizer["SwalContent"]" SwalFooter="@Localizer["SwalFooter"]" />
    </div>
</div>

@code {
    private IEnumerable<SelectedItem> Items { get; set; } = new[]
    {
        new SelectedItem ("Beijing", "北京"),
        new SelectedItem ("Shanghai", "上海") { Active = true },
    };

    private static Task<bool> OnBeforeSelectedItemChange(SelectedItem item)
    {
        return Task.FromResult(true);
    }
}

Display Template

Custom UI of display template

Demo

<div class="row">
    <div class="col-12 col-sm-6">
        <Select TValue="string" Items="Items">
            <DisplayTemplate>
                <i class="fa-solid fa-flag"></i>
                <span>@context?.Text</span>
            </DisplayTemplate>
        </Select>
    </div>
</div>

@code {
    private IEnumerable<SelectedItem> Items { get; set; } = new[]
    {
        new SelectedItem ("Beijing", "北京"),
        new SelectedItem ("Shanghai", "上海") { Active = true },
    };
}

Timezone

Display data of Timezone

Demo

08:00:00

<div class="row g-3">
    <div class="col-12 col-sm-6">
        <Select TValue="string" Value="@TimezoneId" Items="TimezoneItems" OnValueChanged="OnTimezoneValueChanged" />
    </div>
    <div class="col-12 col-sm-6">
        <Display TValue="TimeSpan" Value="@TimezoneValue" />
    </div>
</div>

@code {
    [NotNull]
    private IEnumerable<SelectedItem>? TimezoneItems { get; set; }

    private string? TimezoneId { get; set; }

    [NotNull]
    private TimeSpan TimezoneValue { get; set; }

    private Task OnTimezoneValueChanged(string timezoneId)
    {
        TimezoneId = timezoneId;
        TimezoneValue = TimeZoneInfo.GetSystemTimeZones().First(i => i.Id == timezoneId).BaseUtcOffset;
        StateHasChanged();
        return Task.CompletedTask;
    }

    protected override void OnInitialized()
    {
        TimeZoneInfo.ClearCachedData();
        TimezoneItems = TimeZoneInfo.GetSystemTimeZones().Select(i => new SelectedItem(i.Id, i.DisplayName));
        TimezoneId = TimeZoneInfo.Local.Id;
        TimezoneValue = TimeZoneInfo.Local.BaseUtcOffset;
    }
}

Set IsPopover to true, use popover render UI prevent The dropdown menu cannot be fully displayed because the parent container is set to overflow: hidden

Demo

<div class="row">
    <div class="col-12 col-sm-6 overflow-hidden">
        <Select TValue="string" Items="Items" IsPopover="true" ShowSearch="true" />
    </div>
</div>

@code {
    private IEnumerable<SelectedItem> Items { get; set; } = new[]
    {
        new SelectedItem ("Beijing", "北京"),
        new SelectedItem ("Shanghai", "上海") { Active = true },
    };
}

Select

When there are too many options, use the drop-down menu to present and select content

Demo

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Attributes

Event

Bootstrap Blazor Component library updated to 7.4.4-beta01