Blazor EditForm添加InputNumber字段

Question

我有一个这样的Blazor EditForm：

<EditForm Model="EntryModel" OnValidSubmit="HandleValidSubmit" @oninput="OnInput" >
                    //...other stuff...
                    @foreach (var v in EntryModel.VehiclePremiums)
                    {
                        <tr>
                            <td>@v.vehicleid</td>
                            <td>@v.vehicleMake</td>
                            <td>@v.vehicleModel</td>
                            <td><InputNumber @bind-Value="@v.premium" /></td>
                        </tr>
                        
                    }
                   //...other stuff
</EditForm>

现在，当用户在InputNumber字段中键入内容时，我想对所有这些字段上的值求和。 因此，在OnInput函数中，我这样做：

public void OnInput(){
    total_premium = EntryModel.VehiclePremiums.Select(vp => vp.premium).Sum();
}

这给了我这样的形式：

问题是，当我为第一辆车输入溢价时，总数没有更新。当我进入第二辆车时，总数会更新，但不包括当前值。有点奇怪的行为。总和总是落后一个字段。

当用户输入时（在输入时或失去焦点后，没关系），我应该如何总结这些字段？

Answer 1

此处已测试代码...

请注意，我没有使用InputNumber组件。使用HTML输入数字标签更容易，更灵活

@page "/"

<EditForm Model="entryModel" OnValidSubmit="HandleValidSubmit">
    <InputText @bind-Value="entryModel.ID"></InputText>
    <table>
        <thead>
            <tr>
                <td>Make</td>
                <td>Model</td>
                <td>Premium</td>
                <td>@total_premium.ToString()</td>
            </tr>
        </thead>
        <tbody>
            @foreach (var v in entryModel.VehiclePremiums)
            {
                <tr>
                    <td>@v.VehicleID</td>
                    <td>@v.VehicleMake</td>
                    <td>@v.VehicleModel</td>
                    <td>
                        <input type="number" value="@v.Premium" @onchange="@((args) => { v.Premium = Convert.ToInt32(args.Value);
                                      total_premium = entryModel.VehiclePremiums.Select(vp => vp.Premium).Sum();})" />
                   </td>
                
                </tr>
            }
        </tbody>
    </table>

</EditForm>


@code
{
    private EntryModel entryModel;
    private int total_premium;

  
    private void HandleValidSubmit()
    {

    }

    protected override void OnInitialized()
    {
        entryModel = new EntryModel
        {
            ID = "1",
            VehiclePremiums = new List<VehiclePremium>
                           {
                  new VehiclePremium{VehicleID = "1",  VehicleMake="Make1", VehicleModel="Model1", Premium=0},
                  new VehiclePremium{VehicleID = "2",  VehicleMake="Make2", VehicleModel="Model2", Premium=0},
                  new VehiclePremium{VehicleID = "3",  VehicleMake="Make3", VehicleModel="Model3", Premium=0},
                  new VehiclePremium{VehicleID = "4",  VehicleMake="Make4", VehicleModel="Model4", Premium=0}
                 }
        };
    }


    public class VehiclePremium
    {
        public string VehicleID { get; set; }
        public string VehicleMake { get; set; }
        public string VehicleModel { get; set; }
        public int Premium { get; set; }

    }

    public class EntryModel
    {
        public string ID { get; set; }
        public List<VehiclePremium> VehiclePremiums { get; set; }
    }

}