Hello everyone,

in the web app we are programming, we make heavy use of the TelerikCombobox. Now the use case arises, that the user needs to be able to select a numeric value (double or int, mainly) out of an existing list of values, or if the needed value does not exist yet, provide a custom value.

In this particular case, he selects out of a range of existing article lengths or widths. Most of the time, the length or width is of a "normed" width or length (meaning the normal width / length the article would have) Since they can however produce an article in any width / length they wish to, it does happen sometimes, that the range of existing article widths / lengths is missing the desired value. Hence we thought we could make use of the AllowCustom feature of the TelerikCombobox, so that the user can provide a value themselfes, if need be.

However, the type restriction to string of the Value and Text-Field of the Items makes it rather cumbersome todo so, as a new Model class is needed which has the Text / Value fields as string and internally maps it to the desired type. In addition the user can provide input, which does not make any sense whatsoever for the underlying type.

Would it be possible, for the AllowCustom feature to work also mit numeric values? I.e. When the property the Value-field is referencing to, returns a numeric value, only numeric input is considered (somewhat similar to the NumericTextBox)?

Best Regards,

tilt32

Replication code:

@SelectedValue
<br />
<TelerikComboBox Data="@DdoData"
                 OnRead="@OnReadHandler"
                 Filterable="true"
                 ValueField="RecId"
                 TextField="DdoTitle"
                 Placeholder="Find what you seek by typing"
                 @bind-Value="@SelectedValue">
</TelerikComboBox>

@code{
    public int SelectedValue { get; set; } = 4;
    List<ddo> DdoData { get; set; }
    public string ddoCbType { get; set; } = "Default";
    int InitialId { get; set; }
    string currentText { get; set; } = "";

    protected override async Task OnInitializedAsync()
    {
        await ReadDdoData(ddoCbType, "");
        if (SelectedValue > 0)
        {
            InitialId = (int)SelectedValue;
            await ReadDdoData(ddoCbType, currentText);
        }
    }

    async Task OnReadHandler(ComboBoxReadEventArgs args)
    {
        if (args.Request.Filters.Count > 0)
        {
            Telerik.DataSource.FilterDescriptor filter = args.Request.Filters[0] as Telerik.DataSource.FilterDescriptor;
            currentText = filter.Value.ToString();
            await ReadDdoData(ddoCbType, currentText);
        }
        else
        {
            currentText = "";
            await ReadDdoData(ddoCbType, "");
        }
    }

    private async Task ReadDdoData(string ddoCbType, string currentText)
    {
        await Task.Delay(100);

        DdoData = new List<ddo>()
        {
                new ddo(){ RecId = 1, DdoTitle = "one"},
                new ddo(){ RecId = 2, DdoTitle = "two"},
                new ddo(){ RecId = 3, DdoTitle = "Three"},
                new ddo(){ RecId = 4, DdoTitle = "Four"},
                new ddo(){ RecId = 5, DdoTitle = "Five"}
            };

        //this does not help
        await InvokeAsync(StateHasChanged);
    }

    public class ddo
    {
        public int RecId { get; set; }
        public string DdoTitle { get; set; }
    }
}

Hi

I have an TelerikComboBox for selecting a "site". I use Filterable + FilterOperator (StringFilterOperator.Contains). The "Data" contains almost 2500 sites.



So, my problem is that it is slow when start writing in the combobox. I know for auto-complete you can choose to have a minimum characters before filtering kicks in (MinLength parameter), can you achieve that somehow? Or is it any other way of speeding up the search?



Regards

Emanuel

---

ADMIN EDIT

For the time being, you can see how to achieve that through the OnRead event: https://docs.telerik.com/blazor-ui/knowledge-base/combo-debounce-onread

---

When I select an item from the combo box dropdown, the OnChange event fires with the new value, but the model field is not updated yet.

@selectedValue

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

@code {
    int selectedValue { get; set; }

    IEnumerable<MyDdlModel> myDdlData = Enumerable.Range(1, 20).Select(x => new MyDdlModel { MyTextField = "item " + x, MyValueField = x });
    
    private void MyOnChangeHandler(object theUserInput)
    {
        Console.WriteLine($"COMBO: the models is now {selectedValue} and the handler received {theUserInput}");
    }

    public class MyDdlModel
    {
        public int MyValueField { get; set; }
        public string MyTextField { get; set; }
    }
}

Would be fine if when you click on a filterable combobox the whole text in it will be selected, so you can click and start digit new text filter without delete the old text before.

---

ADMIN EDIT

This should probably be behind a flag to keep the original behavior.

At the moment, you can achieve it with a bit of JS to focus and select all the text:

    <script>
        function selectAllText(parentElem) {
            let input = parentElem.querySelector(".k-input");
            if (input && input.focus) {
                input.select();
            }
        }
    </script>

Which you can call with the approach from this article:

@inject IJSRuntime _js

@SelectedValue
<br />

<span @onfocusin="@SelectAllText" @ref="@spanRef">
    <TelerikComboBox Data="@Data"
                     Filterable="true" FilterOperator="@StringFilterOperator.Contains"
                     Placeholder="Find product by typing part of its name"
                     @bind-Value="@SelectedValue" 
                     TextField="ProductName" ValueField="ProductName" AllowCustom="true">
    </TelerikComboBox>
</span>

@code {
    ElementReference spanRef { get; set; }
    async Task SelectAllText()
    {
        await _js.InvokeVoidAsync("selectAllText", spanRef);
    }

    public List<Product> Data { get; set; }
    public string SelectedValue { get; set; }

    protected override void OnInitialized()
    {
        List<Product> products = new List<Product>();
        for (int i = 0; i < 20; i++)
        {
            products.Add(new Product()
            {
                ProductId = i,
                ProductName = $"Product {i}"
            });
        }

        Data = products;
        base.OnInitialized();
    }

    public class Product
    {
        public int ProductId { get; set; }
        public string ProductName { get; set; }
    }
}

Related to https://docs.telerik.com/blazor-ui/knowledge-base/grid-bind-navigation-property-complex-object

However I'm looking to do this for the Combobox, i.e.

<TelerikComboBox Data="@Users"                               
                                 @bind-Value="@FormElement.UserInitials"
                                 ValueField="Dto.UserInitials"                                 
                                 TextField="Dto.UserInitials"
               >
</TelerikComboBox>

public class Users

{

   //bunch of properties 

   public UserSubProperties Dto {get; set;}

}

public class UserSubProperties

{

   public string UserInitials {get; set;}

}

ComboBox value binding broken in 2.9.0, works fine in 2.8.0

Please see your own documentation example:

<TelerikComboBox Data="@MyList" @bind-Value="MyItem">
</TelerikComboBox>

@code {
    protected List<string> MyList = new List<string>() { "first", "second", "third" };
    protected string MyItem { get; set; } = "second";
}

When i search for something by typing in combobox, i want to be able to use the keyboard to make my selection

Exable below, if i press b, I want to be able to either select baseboll by pressing enter, or make another selection by using arrow keys and then enter. 

Hi,

If I enter some characters in the ComboBox to filter it, the characters that I enter aren't shown and the filtering is not correct. Indeed, if I enter "ALU" (some of my data start with "ALU", no data appears.

I want to capture the user selection (which has to happen through ValueChanged, as OnChange does not fire when I need it). At this point I want to use the selection from the user and to clear the combo box.

I would expect that this should work but it does not:

@result
<br />
from model: @MyItem
<br />
<br />
<TelerikComboBox Data="@MyList" Value="@MyItem" ValueChanged="@( (string v) => MyValueChangeHandler(v) )" Placeholder="Choose something">
</TelerikComboBox>

@code {
    string result;
    private async Task MyValueChangeHandler(string theUserChoice)
    {
        result = string.Format("The user chose: {0}", theUserChoice);

        MyItem = null; // this should be enough

    }
    protected List<string> MyList = new List<string>() { "first", "second", "third" };
    protected string MyItem { get; set; } = "second";
}