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");
    }
}

Completed
Last Updated: 03 Jul 2019 11:47 by ADMIN
Release 1.3.0
Created by: Andrew
Comments: 0
Category: DropDownList
Type: Feature Request
5

Posting this feature request as per your suggestion in my original forum post at: https://www.telerik.com/forums/data-source-using-scalar-list

I would like the DropDownList component to support lists of scalar values as data source. I.e:


<TelerikDropDownList Data="@MyList" bind-Value=@MyItem>

</TelerikDropDownList>
 
@functions {
    protected List<string> MyList = new List<string>() { "a", "b", "c" };
 
    protected string MyItem { get; set; } = "b";
}

The DropDownList would infer the scalar type from the Data property. The TextField items shown in the list (and the associated ValueField) would be the same: i.e. the value of each scalar in the list.

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