如何在C#的RestRequest中为JSON的message属性赋值变量

Hey there! I see you want to swap out that hardcoded message value in your JSON payload for a variable—smart move, this makes your code way more reusable and easier to maintain. Let's walk through a few reliable approaches, from quick fixes to the most robust solution:

1. String Interpolation (C# 6+) #

This is a straightforward way if you want to stick with string-based JSON. Just define your message variable, then use interpolated strings (with a verbatim @ string to avoid escaping newlines, and double curly braces {{}} to preserve the JSON braces):

// Define your message variable first
var messageValue = "c3BlZWQgZXhjZWVkZWQh"; // Or any dynamic value you need

var client = new RestClient("172.16.255.254:2016/settings");
client.Timeout = -1;
var request = new RestRequest(Method.POST);
request.AddHeader("Content-Type", "application/json");

// Use interpolated verbatim string to insert the variable
var jsonPayload = $@"{{
    ""_id"": ""98e8d3cd47fad6ce8e3f7b8d42cb4d9b"",
    ""_type"": ""SetRealtimeMessage"",
    ""message"": ""{messageValue}"",
    ""width"":240,
    ""fontBackground"":0,
    ""fontColor"": 0xFFFFBF00,
    ""fontSize"": 24,
    ""lineSpace"": 0,
    ""left"": 0,
    ""windowBackground"": 0,
    ""verticalPos"": 0,
    ""horizontalPos"": 0,
    ""showType"": 0,
    ""speed"": 20,
    ""moveCount"": 1,
    ""residenceTime"": -1
}}";

request.AddParameter("application/json", jsonPayload, ParameterType.RequestBody);
IRestResponse response = client.Execute(request);
Console.WriteLine(response.Content);

2. String.Format (Older C# Versions) #

If you're working with a pre-C# 6 project, String.Format works similarly—you'll just use placeholders like {0} instead of interpolated variables:

var messageValue = "c3BlZWQgZXhjZWVkZWQh";
var jsonPayload = string.Format(@"{{
    ""_id"": ""98e8d3cd47fad6ce8e3f7b8d42cb4d9b"",
    ""_type"": ""SetRealtimeMessage"",
    ""message"": ""{0}"",
    ""width"":240,
    ""fontBackground"":0,
    ""fontColor"": 0xFFFFBF00,
    ""fontSize"": 24,
    ""lineSpace"": 0,
    ""left"": 0,
    ""windowBackground"": 0,
    ""verticalPos"": 0,
    ""horizontalPos"": 0,
    ""showType"": 0,
    ""speed"": 20,
    ""moveCount"": 1,
    ""residenceTime"": -1
}}", messageValue);

3. Use a Strongly-Typed Class + JSON Serialization (Recommended) #

This is the best long-term approach—no more messy string escaping or syntax errors in your JSON. You'll create a class that matches your JSON structure, populate its properties (including your dynamic message), then serialize it to JSON.

First, define the class:

public class SetRealtimeMessageRequest
{
    public string _id { get; set; }
    public string _type { get; set; }
    public string message { get; set; }
    public int width { get; set; }
    public int fontBackground { get; set; }
    public int fontColor { get; set; }
    public int fontSize { get; set; }
    public int lineSpace { get; set; }
    public int left { get; set; }
    public int windowBackground { get; set; }
    public int verticalPos { get; set; }
    public int horizontalPos { get; set; }
    public int showType { get; set; }
    public int speed { get; set; }
    public int moveCount { get; set; }
    public int residenceTime { get; set; }
}

Then use it in your code (using Newtonsoft.Json, which is common with RestSharp; or System.Text.Json if you prefer):

var messageValue = "c3BlZWQgZXhjZWVkZWQh";

var client = new RestClient("172.16.255.254:2016/settings");
client.Timeout = -1;
var request = new RestRequest(Method.POST);
request.AddHeader("Content-Type", "application/json");

// Populate the request object
var requestPayload = new SetRealtimeMessageRequest
{
    _id = "98e8d3cd47fad6ce8e3f7b8d42cb4d9b",
    _type = "SetRealtimeMessage",
    message = messageValue,
    width = 240,
    fontBackground = 0,
    fontColor = 0xFFFFBF00,
    fontSize = 24,
    lineSpace = 0,
    left = 0,
    windowBackground = 0,
    verticalPos = 0,
    horizontalPos = 0,
    showType = 0,
    speed = 20,
    moveCount = 1,
    residenceTime = -1
};

// Serialize to JSON
var jsonPayload = JsonConvert.SerializeObject(requestPayload, Formatting.Indented);
request.AddParameter("application/json", jsonPayload, ParameterType.RequestBody);

IRestResponse response = client.Execute(request);
Console.WriteLine(response.Content);

Why this is better: #

• No JSON syntax errors: The serializer handles all escaping and formatting for you.
• Type safety: You'll get compile-time errors if you misspell a property name or use the wrong data type.
• Easier to maintain: Updating the payload structure just means modifying the class, not hunting through a string.

内容的提问来源于stack exchange，提问作者Jaswandi Lande