Blazor WebAssembly中InputSelect在CRUD操作中值不更新问题求助

1. 修正ValidationMessage绑定错误 #

代码中存在复制粘贴错误，SurfingQuota和BandwidthPolicy对应的ValidationMessage指向了错误属性，这会导致验证逻辑异常，甚至阻止表单正常提交：

错误代码：

<!-- SurfingQuota区域的ValidationMessage -->
<ValidationMessage For="@(()=>package.SurfingQuotaPolicy)" />
<!-- BandwidthPolicy区域的ValidationMessage -->
<ValidationMessage For="@(()=>package.SurfingQuotaPolicy)" />

修正后：

<!-- SurfingQuota区域 -->
<ValidationMessage For="@(()=>package.SurfingQuotaId)" />
<!-- BandwidthPolicy区域 -->
<ValidationMessage For="@(()=>package.BandwidthPolicyId)" />

2. 将事件处理方法从async void改为async Task #

Blazor中事件处理方法使用async void会导致异步操作无法被正确跟踪，可能在数据提交完成前就执行页面跳转，导致更新失败。同时添加请求结果检查，确保API调用成功：

修正后的AddOrUpdatePackage方法：

async Task AddOrUpdatePackage()
{
    if (package.PackageId != 0)
    {
        var result = await _httpClient.PutAsJsonAsync("api/package", package);
        // 检查请求是否成功，避免无效跳转
        if (!result.IsSuccessStatusCode)
        {
            // 可添加错误提示逻辑，比如弹窗或页面提示
            return;
        }
    }
    else
    {
        var result = await _httpClient.PostAsJsonAsync("api/package", package);
        if (!result.IsSuccessStatusCode)
        {
            return;
        }
    }
    NavigationManager.NavigateTo("/packages");
}

3. 确认属性类型匹配 #

检查Package类中SurfingQuotaId和BandwidthPolicyId的类型，确保与下拉框绑定的SurfingQuota.SurfingQuotaId、BandwidthPolicy.BandwidthPolicyId类型一致（通常为int或int?）：

public class Package
{
    // 确保类型与对应实体的ID类型一致
    public int SurfingQuotaId { get; set; }
    public int BandwidthPolicyId { get; set; }
    // 其他属性...
}

public class SurfingQuota
{
    public int SurfingQuotaId { get; set; }
    public string SurfingPolicyName { get; set; }
    // 其他属性...
}

public class BandwidthPolicy
{
    public int BandwidthPolicyId { get; set; }
    public string BandwidthPolicyName { get; set; }
    // 其他属性...
}

4. 可选：添加默认空选项（如果允许为空） #

如果SurfingQuotaId或BandwidthPolicyId允许为空，建议在下拉框顶部添加空选项，避免绑定默认值错误：

<InputSelect class="form-control" @bind-Value="package.SurfingQuotaId">
    <option value="">-- 选择流量配额策略 --</option>
    @foreach (var surfingQuota in surfingPolicies)
    {
        <option value="@surfingQuota.SurfingQuotaId">@surfingQuota.SurfingPolicyName</option>
    }
</InputSelect>

内容的提问来源于stack exchange，提问作者Akshay Patel