你可以尝试这段代码来获取逗号分隔的值/一个值数组来从webAPI返回JSON

 public class CategoryController : ApiController
 {
     public List<Category> Get(String categoryIDs)
     {
         List<Category> categoryRepo = new List<Category>();

         String[] idRepo = categoryIDs.Split(',');

         foreach (var id in idRepo)
         {
             categoryRepo.Add(new Category()
             {
                 CategoryID = id,
                 CategoryName = String.Format("Category_{0}", id)
             });
         }
         return categoryRepo;
     }
 }

 public class Category
 {
     public String CategoryID { get; set; }
     public String CategoryName { get; set; }
 } 

输出:

[
{"CategoryID":"4","CategoryName":"Category_4"}, 
{"CategoryID":"5","CategoryName":"Category_5"}, 
{"CategoryID":"3","CategoryName":"Category_3"} 
]

我的解决方案是创建一个属性来验证字符串，它做了一堆额外的公共功能，包括regex验证，你可以使用它来检查数字，然后我根据需要转换为整数…

你可以这样使用:

public class MustBeListAndContainAttribute : ValidationAttribute
{
    private Regex regex = null;
    public bool RemoveDuplicates { get; }
    public string Separator { get; }
    public int MinimumItems { get; }
    public int MaximumItems { get; }

    public MustBeListAndContainAttribute(string regexEachItem,
        int minimumItems = 1,
        int maximumItems = 0,
        string separator = ",",
        bool removeDuplicates = false) : base()
    {
        this.MinimumItems = minimumItems;
        this.MaximumItems = maximumItems;
        this.Separator = separator;
        this.RemoveDuplicates = removeDuplicates;

        if (!string.IsNullOrEmpty(regexEachItem))
            regex = new Regex(regexEachItem, RegexOptions.Compiled | RegexOptions.Singleline | RegexOptions.IgnoreCase);
    }

    protected override ValidationResult IsValid(object value, ValidationContext validationContext)
    {
        var listOfdValues = (value as List<string>)?[0];

        if (string.IsNullOrWhiteSpace(listOfdValues))
        {
            if (MinimumItems > 0)
                return new ValidationResult(this.ErrorMessage);
            else
                return null;
        };

        var list = new List<string>();

        list.AddRange(listOfdValues.Split(new[] { Separator }, System.StringSplitOptions.RemoveEmptyEntries));

        if (RemoveDuplicates) list = list.Distinct().ToList();

        var prop = validationContext.ObjectType.GetProperty(validationContext.MemberName);
        prop.SetValue(validationContext.ObjectInstance, list);
        value = list;

        if (regex != null)
            if (list.Any(c => string.IsNullOrWhiteSpace(c) || !regex.IsMatch(c)))
                return new ValidationResult(this.ErrorMessage);

        return null;
    }
}

正如Filip W指出的那样，你可能不得不求助于这样的自定义模型绑定器(修改为绑定到实际的参数类型):

public IEnumerable<Category> GetCategories([ModelBinder(typeof(CommaDelimitedArrayModelBinder))]long[] categoryIds) 
{
    // do your thing
}

public class CommaDelimitedArrayModelBinder : IModelBinder
{
    public bool BindModel(HttpActionContext actionContext, ModelBindingContext bindingContext)
    {
        var key = bindingContext.ModelName;
        var val = bindingContext.ValueProvider.GetValue(key);
        if (val != null)
        {
            var s = val.AttemptedValue;
            if (s != null)
            {
                var elementType = bindingContext.ModelType.GetElementType();
                var converter = TypeDescriptor.GetConverter(elementType);
                var values = Array.ConvertAll(s.Split(new[] { ","},StringSplitOptions.RemoveEmptyEntries),
                    x => { return converter.ConvertFromString(x != null ? x.Trim() : x); });

                var typedValues = Array.CreateInstance(elementType, values.Length);

                values.CopyTo(typedValues, 0);

                bindingContext.Model = typedValues;
            }
            else
            {
                // change this line to null if you prefer nulls to empty arrays 
                bindingContext.Model = Array.CreateInstance(bindingContext.ModelType.GetElementType(), 0);
            }
            return true;
        }
        return false;
    }
}

然后你可以说:

/类别?categoryids=1,2,3,4和ASP。NET Web API将正确绑定您的categoryIds数组。

你可以尝试这段代码来获取逗号分隔的值/一个值数组来从webAPI返回JSON

 public class CategoryController : ApiController
 {
     public List<Category> Get(String categoryIDs)
     {
         List<Category> categoryRepo = new List<Category>();

         String[] idRepo = categoryIDs.Split(',');

         foreach (var id in idRepo)
         {
             categoryRepo.Add(new Category()
             {
                 CategoryID = id,
                 CategoryName = String.Format("Category_{0}", id)
             });
         }
         return categoryRepo;
     }
 }

 public class Category
 {
     public String CategoryID { get; set; }
     public String CategoryName { get; set; }
 } 

输出:

[
{"CategoryID":"4","CategoryName":"Category_4"}, 
{"CategoryID":"5","CategoryName":"Category_5"}, 
{"CategoryID":"3","CategoryName":"Category_3"} 
]

所有其他解决方案都需要大量的工作。我试图在HttpGet方法参数中使用IEnumerable<long>或long[]，但我认为没有必要做所有的工作，只是为了使处理程序方法参数的签名long[]。我最终只是把它变成字符串，然后在处理程序中把它分开。我只说了一句。

public async Task<IActionResult> SomeHandler(string idsString)
{
    var ids = idsString.Split(',').Select(x => long.Parse(x));

现在你可以传递这些数字

.../SomeHandler?idsString=123,456,789,012

除了使用自定义ModelBinder，还可以使用带有TypeConverter的自定义类型。

[TypeConverter(typeof(StrListConverter))]
public class StrList : List<string>
{
    public StrList(IEnumerable<string> collection) : base(collection) {}
}

public class StrListConverter : TypeConverter
{
    public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
    {
        return sourceType == typeof(string) || base.CanConvertFrom(context, sourceType);
    }

    public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
    {
        if (value == null)
            return null;

        if (value is string s)
        {
            if (string.IsNullOrEmpty(s))
                return null;
            return new StrList(s.Split(','));
        }
        return base.ConvertFrom(context, culture, value);
    }
}

它的优点是使Web API方法的参数非常简单。你甚至不需要指定[FromUri]。

public IEnumerable<Category> GetCategories(StrList categoryIds) {
  // code to retrieve categories from database
}

这个例子是一个字符串列表，但你可以使用categoryIds.Select(int.Parse)或简单地编写一个IntList代替。