asp.net-core – 当返回null而不是控制器中设置的值时,Modelbind

public class CustomQueryModelBinder : IModelBinder
{
    public Task<ModelBindingResult> BindModelAsync(ModelBindingContext bindingContext)
    {
      if (!String.IsNullOrWhiteSpace(bindingContext.ModelName) && bindingContext.ModelType == typeof(short) && bindingContext.ValueProvider.GetValue(bindingContext.ModelName) != null)
        {
            short value;
            var val = bindingContext.ValueProvider.GetValue(bindingContext.ModelName).FirstValue as string;

            if (String.IsNullOrWhiteSpace(val))
            {
                return ModelBindingResult.SuccessAsync(bindingContext.ModelName,val);
            }
            else if (Int16.TryParse(val,out value) && value >= 0)
            {
                return ModelBindingResult.SuccessAsync(bindingContext.ModelName,value);
            }
            else
            {
                bindingContext.ModelState.AddModelError(bindingContext.ModelName,"The value is invalid.");
            }
        }

        return ModelBindingResult.FailedAsync(bindingContext.ModelName);
    }
}

并且在URI中未指定自定义值的情况下,它应默认为有效值(大于0),但它始终默认为0,即使控制器如下所示：

public async Task<IActionResult> GetAsync(
        [ModelBinder(BinderType = typeof(CustomQueryModelBinder))]short value = 100,

当从ModelBinder返回null时,这里的基本值应设置为100作为其默认值.

但是这没有发生,并且它一直被返回为0,这在尝试执行Get时导致System.ArgumentOutOfRangeException.

我们正在使用RC1.