DropDownList cancel selection

[Louis]

Hello.

 

I need to cancel a user selection based on  some criteria.  Any idea?  Example, User choose a new item in the dropdownlist and after check something in OnChange event I want to keep the original selection.

 

                       <TelerikDropDownList Data="@infosEtapeMaitriseCategories"                        
                                         @bind-Value="@CurrentlyEditingEtapeMaitrise.tlkpEtapeMaitriseCategorieId"
                                     TextField="TextField" ValueField="ValueField"
                                     Enabled="@tlkpEtapeMaitriseCategorieIdEnabled"                                             
                                     Width="100%">

 

 

[Hristian Stefanov]

Hi Louis,

I can confirm that achieving the desired result is possible by utilizing the OnChange event.

To demonstrate how to cancel a selection based on a condition, I have prepared an example for you:

<TelerikButton OnClick="@TurnOnSelectThird" Enabled="@(!selectThirdOn)">Turn on - Selecting the third option</TelerikButton>

<TelerikDropDownList Data="@MyList"
                     OnChange="@MyOnChangeHandler"
                     @bind-Value="@MySelectedItem"
                     Width="300px"/>

@code {
    bool selectThirdOn = false;
    string MySelectedItem { get; set; } = "second";

    void MyOnChangeHandler(object theUserInput)
    {
        if (theUserInput.ToString() == "third" && !selectThirdOn)
        {
            MySelectedItem = "second";
        }
    }

    void TurnOnSelectThird()
    {
        selectThirdOn = true;
    }

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

Please run the provided sample and test it using the following steps:

1. Open the dropdown.
2. Select the third option. (you will notice that it is not selectable)
3. Click the "Turn on - Selecting the third option" button.
4. Try to select the third option again.

I hope this example meets your requirements. If there is anything I may have overlooked or if you need a more suitable solution, please let me know, and I will gladly assist you further.

Regards,
Hristian Stefanov
Progress Telerik