Completed
Last Updated: 17 Sep 2020 10:55 by ADMIN
Release 2.18.0
I have logic that updates the Data of a dropdownlist (in this case, changes the value of the TextField of a the selected item in the dropdown). After the database update, I fetch the dropdown data anew, and it reflects in the dropdown element, but not in the main element where it is currently shown.
Unplanned
Last Updated: 01 Sep 2020 12:37 by ADMIN
When I place a DropDownList inside a Modal Window and run it in Safari there is a flicker in the UI when the dropdown is expanded.
Completed
Last Updated: 23 Jun 2020 07:39 by ADMIN
Release 2.15.0

Clicking on the <label> opens the dropdown, but clicking on its main element does not

Selected value: @selectedValue
<br />
<label>some label for the dropdown, open it and test whether clicking outside closes it
    <TelerikDropDownList Data="@myDdlData" TextField="MyTextField" ValueField="MyValueField" @bind-Value="selectedValue">
    </TelerikDropDownList>
</label>

@code {
    //in a real case, the model is usually in a separate file
    //the model type and value field type must be provided to the dropdpownlist
    public class MyDdlModel
    {
        public int MyValueField { get; set; }
        public string MyTextField { get; set; }
    }

    IEnumerable<MyDdlModel> myDdlData = Enumerable.Range(1, 20).Select(x => new MyDdlModel { MyTextField = "item " + x, MyValueField = x });

    int selectedValue { get; set; } = 3; //usually the current value should come from the model data
}

Unplanned
Last Updated: 11 May 2020 12:14 by ADMIN
When I change the PopupHeight dynamically (based on the number of items in my data source), the change is not reflected in the component.
Declined
Last Updated: 23 Apr 2020 20:49 by Ben Hayat
Created by: Rob
Comments: 9
Category: DropDownList
Type: Bug Report
1
The Telerik drop down list seems to be very slow from initial click to when the list is shown. Other Telerik drop down components outside of the Blazor suite seem to be much more responsive and quick. In it's current state I would consider it unusable and will need to switch to InputSelect. Has this been reported or observed before?
Won't Fix
Last Updated: 31 Mar 2020 09:10 by ADMIN
Scheduled for 2.10.0

Before, the Value from the first item in the Data was populated through @bind-Value to the view model. It no longer is.

In the following snippet, I expect to see "1" in the initial load of the page, but I see "0" - the default value for the integer.

@selectedValue

<TelerikDropDownList Data="@myDdlData" TextField="MyTextField" ValueField="MyValueField" @bind-Value="@selectedValue">
</TelerikDropDownList>

@code {
    //in a real case, the model is usually in a separate file
    //the model type and value field type must be provided to the dropdpownlist
    public class MyDdlModel
    {
        public int MyValueField { get; set; }
        public string MyTextField { get; set; }
    }

    IEnumerable<MyDdlModel> myDdlData = Enumerable.Range(1, 20).Select(x => new MyDdlModel { MyTextField = "item " + x, MyValueField = x });

    int selectedValue { get; set; }
}

Unplanned
Last Updated: 13 Feb 2020 10:19 by ADMIN

Hi!

When i use combination of LINQ inside TelerikDropDownLists Data attribute and TelerikGrid 's GridEditMode.Popup mode, i get weird behavior when i try to select an item from TelerikDropDownLists - everything freezes. Please check the solution. Everything works fine if i don't use LINQ or GridEditMode.Popup mode.

 

Thank you!

Completed
Last Updated: 12 Dec 2019 12:39 by ADMIN
Release 2.5.1
Created by: Emil
Comments: 1
Category: DropDownList
Type: Bug Report
0

Hello,

Initial I want no item to be selected to let the user select a value. I thought it would be enough if my bindvalue would be of a nullable type. I'm getting an exception when trying. If this is not supported, how can I do it?

 

     <div class="form-group col-md-2">
        <label class="col-form-label" for="ddReleaseType">Fönstertyp</label>
        <TelerikDropDownList Data="@ReleaseTypeFilterOptions" @bind-Value="FilterState.ReleaseType" TextField="DisplayText" ValueField="ReleaseType" Class="max-width form-control" @ref="ddReleaseType"></TelerikDropDownList>
    </div>

     public enum ReleaseType : int
    {
        All = 0,
        Category = 1,
        Season = 2,
        Misc = 3
    }

    public class FilterState
    {
        public ReleaseType? ReleaseType { get; set; }
    }

 

        protected Telerik.Blazor.Components.TelerikDropDownList<ReleaseTypeFilterModel?, SessionState.ReleaseType?> ddReleaseType;
 

        protected class ReleaseTypeFilterModel
        {
            public SessionState.ReleaseType ReleaseType { get; set; }
            public string DisplayText { get { return ReleaseType.ToString(); } }
        }
 

 

 

 

An unhandled exception occurred while processing the request.

InvalidOperationException: Telerik.Blazor.Components.TelerikDropDownList`2[ReleaseCalendar.Pages.IndexBase+ReleaseTypeFilterModel,System.Nullable`1[ReleaseCalendar.SessionState.ReleaseType]] does not support the type 'System.Nullable`1[ReleaseCalendar.SessionState.ReleaseType]'.

Telerik.Blazor.Components.Common.TelerikSelectBase<TItem, TValue>.TryParseValueFromString(string value, out TValue result, out string validationErrorMessage)

 

    • Telerik.Blazor.Components.Common.TelerikSelectBase<TItem, TValue>.TryParseValueFromString(string value, out TValue result, out string validationErrorMessage)

    • Telerik.Blazor.Components.Common.TelerikSelectBase<TItem, TValue>.set_CurrentValueAsString(string value)

    • Telerik.Blazor.Components.TelerikDropDownListBase<TItem, TValue>.OnParametersSet()

    • Microsoft.AspNetCore.Components.ComponentBase.CallOnParametersSetAsync()

    • Microsoft.AspNetCore.Components.ComponentBase.RunInitAndSetParametersAsync()

    • Microsoft.AspNetCore.Components.Rendering.HtmlRenderer.HandleException(Exception exception)

    • Microsoft.AspNetCore.Components.RenderTree.Renderer.AddToPendingTasks(Task task)

    • Microsoft.AspNetCore.Components.Rendering.ComponentState.SetDirectParameters(ParameterView parameters)

    • Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.InitializeNewComponentFrame(ref DiffContext diffContext, int frameIndex)

    • Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.InitializeNewSubtree(ref DiffContext diffContext, int frameIndex)

    • Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.InsertNewFrame(ref DiffContext diffContext, int newFrameIndex)

    • Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.AppendDiffEntriesForRange(ref DiffContext diffContext, int oldStartIndex, int oldEndIndexExcl, int newStartIndex, int newEndIndexExcl)

    • Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.ComputeDiff(Renderer renderer, RenderBatchBuilder batchBuilder, int componentId, ArrayRange<RenderTreeFrame> oldTree, ArrayRange<RenderTreeFrame> newTree)

    • Microsoft.AspNetCore.Components.Rendering.ComponentState.RenderIntoBatch(RenderBatchBuilder batchBuilder, RenderFragment renderFragment)

    • Microsoft.AspNetCore.Components.RenderTree.Renderer.RenderInExistingBatch(RenderQueueEntry renderQueueEntry)

    • Microsoft.AspNetCore.Components.RenderTree.Renderer.ProcessRenderQueue()

    • Microsoft.AspNetCore.Components.Rendering.HtmlRenderer.HandleException(Exception exception)

    • Microsoft.AspNetCore.Components.RenderTree.Renderer.ProcessRenderQueue()

    • Microsoft.AspNetCore.Components.RenderTree.Renderer.ProcessPendingRender()

    • Microsoft.AspNetCore.Components.RenderTree.Renderer.AddToRenderQueue(int componentId, RenderFragment renderFragment)

    • Microsoft.AspNetCore.Components.ComponentBase.StateHasChanged()

    • Microsoft.AspNetCore.Components.ComponentBase.CallOnParametersSetAsync()

    • Microsoft.AspNetCore.Components.ComponentBase.RunInitAndSetParametersAsync()

    • Microsoft.AspNetCore.Components.Rendering.HtmlRenderer.HandleException(Exception exception)

    • Microsoft.AspNetCore.Components.RenderTree.Renderer.AddToPendingTasks(Task task)

    • Microsoft.AspNetCore.Components.Rendering.ComponentState.SetDirectParameters(ParameterView parameters)

    • Microsoft.AspNetCore.Components.RenderTree.Renderer.RenderRootComponentAsync(int componentId, ParameterView initialParameters)

    • Microsoft.AspNetCore.Components.Rendering.HtmlRenderer.CreateInitialRenderAsync(Type componentType, ParameterView initialParameters)

    • Microsoft.AspNetCore.Components.Rendering.HtmlRenderer.RenderComponentAsync(Type componentType, ParameterView initialParameters)

    • Microsoft.AspNetCore.Components.Rendering.RendererSynchronizationContext+<>c__11<TResult>+<<InvokeAsync>b__11_0>d.MoveNext()

    • Microsoft.AspNetCore.Mvc.ViewFeatures.StaticComponentRenderer.PrerenderComponentAsync(ParameterView parameters, HttpContext httpContext, Type componentType)

    • Microsoft.AspNetCore.Mvc.ViewFeatures.ComponentRenderer.PrerenderedServerComponentAsync(HttpContext context, ServerComponentInvocationSequence invocationId, Type type, ParameterView parametersCollection)

    • Microsoft.AspNetCore.Mvc.ViewFeatures.ComponentRenderer.RenderComponentAsync(ViewContext viewContext, Type componentType, RenderMode renderMode, object parameters)

    • Microsoft.AspNetCore.Mvc.TagHelpers.ComponentTagHelper.ProcessAsync(TagHelperContext context, TagHelperOutput output)

    • Microsoft.AspNetCore.Razor.Runtime.TagHelpers.TagHelperRunner.<RunAsync>g__Awaited|0_0(Task task, TagHelperExecutionContext executionContext, int i, int count)

    • ReleaseCalendar.Pages.Pages__Host.<ExecuteAsync>b__14_1() in _Host.cshtml

      1.     <app><component type="typeof(App)" render-mode="ServerPrerendered" /></app>
    • Microsoft.AspNetCore.Razor.Runtime.TagHelpers.TagHelperExecutionContext.SetOutputContentAsync()

    • ReleaseCalendar.Pages.Pages__Host.ExecuteAsync()

    • Microsoft.AspNetCore.Mvc.Razor.RazorView.RenderPageCoreAsync(IRazorPage page, ViewContext context)

    • Microsoft.AspNetCore.Mvc.Razor.RazorView.RenderPageAsync(IRazorPage page, ViewContext context, bool invokeViewStarts)

    • Microsoft.AspNetCore.Mvc.Razor.RazorView.RenderAsync(ViewContext context)

    • Microsoft.AspNetCore.Mvc.ViewFeatures.ViewExecutor.ExecuteAsync(ViewContext viewContext, string contentType, Nullable<int> statusCode)

    • Microsoft.AspNetCore.Mvc.ViewFeatures.ViewExecutor.ExecuteAsync(ViewContext viewContext, string contentType, Nullable<int> statusCode)

    • Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeNextResultFilterAsync>g__Awaited|29_0<TFilter, TFilterAsync>(ResourceInvoker invoker, Task lastTask, State next, Scope scope, object state, bool isCompleted)

    • Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResultExecutedContextSealed context)

    • Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.ResultNext<TFilter, TFilterAsync>(ref State next, ref Scope scope, ref object state, ref bool isCompleted)

    • Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeResultFilters()

    • Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeNextResourceFilter>g__Awaited|24_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, object state, bool isCompleted)

    • Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResourceExecutedContextSealed context)

    • Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next(ref State next, ref Scope scope, ref object state, ref bool isCompleted)

    • Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeFilterPipelineAsync()

    • Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Logged|17_1(ResourceInvoker invoker)

    • Microsoft.AspNetCore.Routing.EndpointMiddleware.<Invoke>g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)

    • Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)


Completed
Last Updated: 26 Jul 2019 07:50 by ADMIN
Release 1.4.0

When bound to a nullable GUID, the DropDownList invokes validation and shows validation messages as soon as the view loads.

Expected: the same behavior as with nullable int - validation is to be triggered by the form submission or selection from the dropdown.

Worked as expected in 1.2.0.

Reproducible:

@using Telerik.Blazor.Components.DropDownList
@using System.ComponentModel.DataAnnotations
 
<EditForm Model="@person" OnValidSubmit="@HandleValidSubmit">
    <DataAnnotationsValidator />
    <ValidationSummary />
    <p class="gender">
        Gender: <TelerikDropDownList @bind-Value="person.Gender" DefaultItem="@ddlHint"
                                   Data="@genders" TextField="MyTextField" ValueField="MyValueField">
        </TelerikDropDownList>
        <ValidationMessage For="@(() => person.Gender)"></ValidationMessage>
    </p>
 
    <button type="submit">Submit</button>
</EditForm>
 
@code {
    // Usually the model classes would be in different files
    public class Person
    {
        [Required(ErrorMessage = "Gender is mandatory.")]//the value field in the dropdown model must be null in the default item
        public Guid? Gender { get; set; }
    }
 
    public class MyDdlModel
    {
        //nullable so the default item can allow required field validation
        public Guid? MyValueField { get; set; }
        public string MyTextField { get; set; }
    }
 
    Person person = new Person();
 
    MyDdlModel ddlHint = new MyDdlModel { MyValueField = null, MyTextField = "Gender" };
 
    IEnumerable<MyDdlModel> genders = new List<MyDdlModel>
{
        new MyDdlModel {MyTextField = "female", MyValueField = new Guid()},
        new MyDdlModel {MyTextField = "male", MyValueField = new Guid()},
        new MyDdlModel {MyTextField = "other", MyValueField = new Guid()},
        new MyDdlModel {MyTextField = "I'd rather not say", MyValueField = new Guid()}
    };
 
    void HandleValidSubmit()
    {
        Console.WriteLine("OnValidSubmit");
    }
}

Completed
Last Updated: 03 Jul 2019 11:47 by ADMIN
Release 1.3.0
Created by: Oliver
Comments: 2
Category: DropDownList
Type: Bug Report
2

When the Value you bind to the DropDownList is null (for example, because it is a model that is not filled in by the user yet, and you need to perform validation), the component throws a null reference exception.

This does not happen for a nullable integer (example here)

Reproducible:

@using System.ComponentModel.DataAnnotations
@using Telerik.Blazor.Components.DropDownList
 
    <EditForm Model="@PageData" OnValidSubmit="@HandleValidSubmit">
        <DataAnnotationsValidator />
        <ValidationSummary />
        @PageData.QuoteState
 
        <TelerikDropDownList bind-Value="@PageData.QuoteState" DefaultItem="@Hint" Width="300px"
                             Data="@states" TextField="stateName" ValueField="stateID">
        </TelerikDropDownList>
        <ValidationMessage For="@(() => PageData.QuoteState)"></ValidationMessage>
        <button type="submit">Submit</button>
    </EditForm>
 
@functions {
    public MyViewModel PageData { get; set; } = new MyViewModel();
 
    public statesModel Hint { get; set; } = new statesModel { stateID = null, stateName = "Not Selected" };
 
    public class statesModel
    {
        public string stateID { get; set; }
        public string stateName { get; set; }
    }
 
    public class MyViewModel
    {
        [Required(ErrorMessage = "State is mandatory.")]//the value field in the dropdown model must be null in the default item
        public string QuoteState { get; set; }
    }
 
    public IEnumerable<statesModel> states = new List<statesModel>
    {
            new statesModel { stateID = "ACT", stateName = "ACT" },
            new statesModel { stateID = "NSW", stateName = "NSW" },
            new statesModel { stateID = "NT", stateName = "NT" },
            new statesModel { stateID = "QLD", stateName = "QLD" },
            new statesModel { stateID = "SA", stateName = "SA" },
            new statesModel { stateID = "TAS", stateName = "TAS" },
            new statesModel { stateID = "VIC", stateName = "VIC" },
            new statesModel { stateID = "WA", stateName = "WA" }
        };
 
    void HandleValidSubmit()
    {
        Console.WriteLine("OnValidSubmit");
    }
}