在 Web 中执行 PUT 时出现 NullObjectReference Api

Question

我正在尝试更新 class "Conversation" 中的变量，因为某些原因，参数对象未绑定。我不知道为什么不。结果我收到这个错误：

"Object reference not set to an instance of an object.",

控制器：

[HttpPut]
public async Task<IHttpActionResult> AddMember(string key, User user)
{
    if (!ModelState.IsValid)
    {
        return BadRequest(ModelState);
    }

    Conversation conver = await db.Conversations.FindAsync(key);     //THIS IS NULL

    if (conver == null)
    {
        return NotFound();      //METHOD IS ENDING HERE
    }

    conver.Members.Add(user);   //THIS IS NULL

    db.Entry(conver).State = EntityState.Modified;
    try
    {
        await db.SaveChangesAsync();
    }
    catch (DbUpdateConcurrencyException)
    {
        return NotFound();
    }

     return StatusCode(HttpStatusCode.NoContent);
}

型号class用户：

namespace AcademicAssistant.Models
{
    [DataContract]
    public class User
    {
        [Key]
        [DataMember]
        public string Email { get; set; }

        [DataMember]
        public string Password { get; set; }

        [DataMember]
        public bool Admin { get; set; }

    }
}

模特Class对话：

[DataContract]
public class Conversation
{
    [Key]
    [DataMember]
    public string Key { get; set; }

    [DataMember]
    public string ConversationName { get; set; }

    [DataMember]
    public string Administrator { get; set; }

    [DataMember]
    public virtual ICollection<User> Members { get; set; }

    [DataMember]
    public virtual ICollection<Message> Messages { get; set; }

}

我正在 Postman 中这样测试它：

路线 = api/Conversations/AddMember/?key="1LM4"

JSON = {"user": { "Email": "56@56.com", "Password" : "Passw-1", "Admin" : true } }

Answer 1

解决方案：

路线应该是

api/Conversations/AddMember/?key=1LM4

和 JSON 格式如下：

{
    "Email": "56@56.com",
    "Password" : "Passw-1",
    "Admin" : true
}

在 Web 中执行 PUT 时出现 NullObjectReference Api

NullObjectReference when performing a PUT in Web Api

http-put

nullreferenceexception

asp.net-web-api2