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首页 > 解决方案 > 我如何将 MQTT 从字符串解析为在 c#/unity 中浮动？

c# - 我如何将 MQTT 从字符串解析为在 c#/unity 中浮动？

问题描述

我试图为我的统一项目开发一个 mqtt 字符串，使用 m2mqttunity 订阅和接收来自发布者的消息。我已成功订阅并收到消息和日志。问题是，我似乎无法找到将有效负载字符串消息解析为浮点数的方法，因此我可以将浮点数用作我的统一演示的温度输入。我得到的错误是：

System.FormatException: Input string was not in a correct format.
  at System.Number.StringToNumber (System.String str, System.Globalization.NumberStyles options, System.Number+NumberBuffer& number, System.Globalization.NumberFormatInfo info, System.Boolean parseDecimal) [0x00057] in <437ba245d8404784b9fbab9b439ac908>:0 
  at System.Number.ParseInt32 (System.String s, System.Globalization.NumberStyles style, System.Globalization.NumberFormatInfo info) [0x00013] in <437ba245d8404784b9fbab9b439ac908>:0 
  at System.Int32.Parse (System.String s) [0x00007] in <437ba245d8404784b9fbab9b439ac908>:0 
  at mqttTest.client_MqttMsgPublishReceived (System.Object sender, uPLibrary.Networking.M2Mqtt.Messages.MqttMsgPublishEventArgs e) [0x00021] in C:\Users\Tila\Unity3d_MQTT-master\Assets\MQTT\scripts\test\mqttTest.cs:38 
  at uPLibrary.Networking.M2Mqtt.MqttClient.OnMqttMsgPublishReceived (uPLibrary.Networking.M2Mqtt.Messages.MqttMsgPublish publish) [0x0000f] in C:\Users\Tila\Unity3d_MQTT-master\Assets\MQTT\scripts\MqttClient.cs:764 
  at uPLibrary.Networking.M2Mqtt.MqttClient.ReceiveEventThread () [0x000f8] in C:\Users\Tila\Unity3d_MQTT-master\Assets\MQTT\scripts\MqttClient.cs:1487 
  at System.Threading.ThreadHelper.ThreadStart_Context (System.Object state) [0x00014] in <437ba245d8404784b9fbab9b439ac908>:0 
  at System.Threading.ExecutionContext.RunInternal (System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, System.Object state, System.Boolean preserveSyncCtx) [0x00071] in <437ba245d8404784b9fbab9b439ac908>:0 
  at System.Threading.ExecutionContext.Run (System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, System.Object state, System.Boolean preserveSyncCtx) [0x00000] in <437ba245d8404784b9fbab9b439ac908>:0 
  at System.Threading.ExecutionContext.Run (System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, System.Object state) [0x0002b] in <437ba245d8404784b9fbab9b439ac908>:0 
  at System.Threading.ThreadHelper.ThreadStart () [0x00008] in <437ba245d8404784b9fbab9b439ac908>:0  occurred

GIT 是

using UnityEngine;
using System.Collections;
using System.Net;
using uPLibrary.Networking.M2Mqtt;
using uPLibrary.Networking.M2Mqtt.Messages;
using uPLibrary.Networking.M2Mqtt.Utility;
using uPLibrary.Networking.M2Mqtt.Exceptions;

using System;

public class mqttTest : MonoBehaviour {
	private MqttClient client;
	public int tempDemo;
	
	// Use this for initialization
	void Start () {
		
		// create client instance 
		client = new MqttClient(IPAddress.Parse("127.0.0.1"),1883, false , null ); 
		
		// register to message received 
		client.MqttMsgPublishReceived += client_MqttMsgPublishReceived; 
		
		string clientId = Guid.NewGuid().ToString(); 
		client.Connect(clientId); 
		
		// subscribe to the topic "/home/temperature" with QoS 2 
		client.Subscribe(new string[] { "hello/world" }, new byte[] { MqttMsgBase.QOS_LEVEL_EXACTLY_ONCE });

		


	}
	void client_MqttMsgPublishReceived(object sender, MqttMsgPublishEventArgs e) 
	{ 

		Debug.Log("Received: " + System.Text.Encoding.UTF8.GetString(e.Message)  );
		tempDemo = int.Parse(System.Text.Encoding.UTF8.GetString(e.Message));

	} 

	void OnGUI(){
		if ( GUI.Button (new Rect (20,40,80,20), "Level 1")) {
			Debug.Log("sending...");
			client.Publish("hello/world", System.Text.Encoding.UTF8.GetBytes("bro"), MqttMsgBase.QOS_LEVEL_EXACTLY_ONCE, true);
			Debug.Log("sent");
		}
	}


	// Update is called once per frame
	void Update () {



	}
}

标签： c#unity3dmqtt

解决方案

您的 client_MqttMsgPublishReceived 方法有tempDemo = int.Parse(...)

但是您建议传入的数据是浮点数。int.Parse不会解析浮点数和双精度数，因为您需要float.Parse或double.Parse。您始终可以将非整数数字转换（截断）为 int。

可能的修复：

tempDemo = (int)double.Parse(System.Text.Encoding.UTF8.GetString(e.Message));

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