将 html 输入的选中属性绑定到 blazor 中的 boolean 方法返回值

Question

I am working on a blazor project currenty. In this project I need to add some default values to a list in my C# code. The problem is that I can not find a way to bind a boolean method return value to the "checked" attribute of an input.

Code:

I do have a list and I am adding an input (checkbox) field per entry in this list to my html:

@foreach (ProfessionViewModel prof in Professions)
{
    <div class="form-group m-1">
        <div class="form-check">

            <input class="form-check-input" type="checkbox" id="@prof.Id" 
                  @onchange="eventArgs => { ToggleProfessions(prof, eventArgs.Value); }" />
                                        
        </div>
    </div>
}

I cant find a way to bind the "checked" attribute to a method that checks if this item exists in an other list (SelectedProfessions list, defined in @code section).

My list:

public List<ProfessionViewModel> SelectedProfessions { get; set; } = new List<ProfessionViewModel>();

My boolean return method:

private bool CheckIfProfessionIsAssigned(ProfessionViewModel prof)
{
    if (SelectedProfessions.Contains(prof))
        return true;
    return false;
}

Problem description:

The collection "Professions" contains all professions available in the app. In this form the user should be able to select certain professions individualy (for a profession filter). Every selected profession is contained in the collection "SelectedProfessions". The problem is that I can't bind (or render) the checkboxes value according to the helper property "CheckIfProfessionIsAssigned", which determines if this profession is currently selected by the user.

Answer 1

Didn't try these myself, but based on this answer - https://stackoverflow.com/a/60343185 - something like this might work to initially check the checkboxes:

<input type="checkbox" checked="@CheckIfProfessionIsAssigned(prof)">

You could alternatively try to create a dictionary of integers and booleans named professionsSelected in which to store for each profession ID if it is selected or not, and then bind that to the checkboxes, like:

<input type="checkbox" @bind="@professionsSelected[prof.Id]" />