英文:
How to pass a null value to a key in a JSON body request
问题
要在API的POST请求中传递一个空值给一个键，你可以像下面这样做。
例如，我想传递以下JSON数据，即Exp和TeamID为null。
{"ID": 162617,"TextKey": "107737","Exp": null,"TeamID": null}
这个结果在Postman中是被接受的，但是当我尝试在C#代码中使用相同的方式传递时，我的JSON内容变得无效。
long idvalue = 162617;string textkeyvalue = "107737";string expvalue = null;long? teamIDvalue = null;string postData = "{\"ID\":" + idvalue + ",\"TextKey\":\"" + textkeyvalue + "\",\"Exp\":" + expvalue + ",\"TeamID\":" + teamIDvalue + "}";
这给我以下输出。
{"ID": 162617,"TextKey": "107737","Exp": "","TeamID":}
我的请求由于无效的JSON主体而失败。那么，如何传递这种类型的null数据或null关键字呢？
注意：在我的API中，所有键值对都是强制的，所以如果它们为null，我不能省略它们。
我只想以以下格式传递数据。
{"ID": 162617,"TextKey": "107737","Exp": null,"TeamID": null}
英文:
I want to pass a null value to a key using a POST request in an API.
For example, I want to pass the below JSON data. That is, Exp and TeamID is null.
<!-- language: json -->
{
"ID":162617,
"TextKey":"107737",
"Exp":null,
"TeamID":null
}
The result is accepted in Postman, but when I tried passing the same using C# code below, my JSON content becomes invalid.
long idvalue = 162617;string textkeyvalue = "107737";string expvalue = null;long? teamIDvalue = null;string postData = "{\"ID\":" + idvalue + ",\"TextKey\":\"" + textkeyvalue + "\",\"Exp\":\"" + expvalue + "\",\"TeamID\":\"" + teamIDvalue + "\"}";
Which gives me the following output.
<!-- language: json -->
{
"ID":162617,
"TextKey":"107737",
"Exp":"",
"TeamID":
}
And my request fails due to the invalid JSON body. So how do i pass this sort of null data or null keyword?
Note : All the Key value pairs are mandatory in my API, so I cannot omit them if they are null.
I just want to pass the data in the below format.
<!-- language: json -->
{
"ID":162617,
"TextKey":"107737",
"Exp":null,
"TeamID":null
}
答案1
得分: 3
以下是翻译好的代码部分：
要回答你的问题，以便为 null 值编写文本，你可以这样做：var result = "my value is " + (strValue ?? "null");
或者要添加引号：var result = "my value is " + (strValue == null ? "null" : $"\"{strValue}\"");
你还可以创建静态辅助方法以使其更容易：static string write(string str) => str == null ? "null" : $"\"{str}\"";static string write(long? value) => value == null ? "null" : value.ToString();
因此，在你的示例中，它变成了：string postData = "{"ID":" + idvalue + ","TextKey":" + write(textkeyvalue) +","Exp":" + write(expvalue) + ","TeamID":" +write(teamIDvalue) + "}";
更好的解决方案！
创建一个用于数据模型的类，并使用库（例如 System.Text.Json）来对其进行序列化，如下所示：
public class MyData{public long ID { get; set; }public string TextKey { get; set; }public string Exp { get; set; }public long? TeamID { get; set; }}// 构造模型var data = new MyData(){ID = 162617,TextKey = "107737",Exp = null,TeamID = null,}// 序列化为 JSONvar result = System.Text.Json.JsonSerializer.Serialize(data);
<details><summary>英文:</summary>To answer your question, to write text for a null value, you can do this:```csvar result = "my value is " + (strValue ?? "null");
Or to add quotes:
var result = "my value is " + (strValue == null ? "null" : $"\"{strValue}\"");
You can also create static helper methods to make it easier:
static string write(string str) => str == null ? "null" : $"\"{str}\"";static string write(long? value) => value == null ? "null" : value.ToString();
So in your example, it becomes:
string postData = "{\"ID\":" + idvalue + ",\"TextKey\":" + write(textkeyvalue) +",\"Exp\":" + write(expvalue) + ",\"TeamID\":" +write(teamIDvalue) + "}";
<br/>
Better solution!
Create a class for the data model, and use a library (for example, System.Text.Json) to serialize it, like so:
public class MyData{public long ID { get; set; }public string TextKey { get; set; }public string Exp { get; set; }public long? TeamID { get; set; }}// Construct modelvar data = new MyData(){ID = 162617,TextKey = "107737",Exp = null,TeamID = null,}// Serialize to JSONvar result = System.Text.Json.JsonSerializer.Serialize(data);
答案2
得分: 3
gepa's answer 答案非常准确，但你也可以序列化一个匿名对象：
long idvalue = 162617;string textkeyvalue = "107737";string? expvalue = null;long? teamIDvalue = null;string postData = System.Text.Json.JsonSerializer.Serialize(new{ID = idvalue,TextKey = textkeyvalue,Exp = expvalue,TeamID = teamIDvalue,});
英文:
gepa’s answer is right on the money, but you can serialize an anonymous object, too:
long idvalue = 162617;string textkeyvalue = "107737";string? expvalue = null;long? teamIDvalue = null;string postData = System.Text.Json.JsonSerializer.Serialize(new{ID = idvalue,TextKey = textkeyvalue,Exp = expvalue,TeamID = teamIDvalue,});
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