IM/backend/SignalRTest/Form1.cs

using Microsoft.AspNetCore.SignalR.Client;
using System.Text.Json;
using System.Windows.Forms;

namespace SignalRTest
{
    public partial class Form1 : Form
    {
        private HubConnection _connection;
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }

        private async void button1_Click(object sender, EventArgs e)
        {
            try
            {
                _connection = new HubConnectionBuilder()
                    .WithUrl(txtUrl.Text, options =>
                    {
                        options.AccessTokenProvider = () =>
                        Task.FromResult(TokenTxt.Text);
                    })
                    .WithAutomaticReconnect()
                    .Build();

                _connection.On<string, string>("ReceiveMessage", (user, message) =>
                {
                    Historylab.Invoke(new Action(() =>
                    {
                        // 移动光标到文本末尾
                        Historylab.SelectionStart = Historylab.TextLength;
                        Historylab.SelectionLength = 0;

                        Historylab.SelectionColor = Color.Green;
                        Historylab.AppendText("接收消息：" + message + "\n");
                    }));
                });

                _connection.Reconnecting += (ex) =>
                {
                    // 移动光标到文本末尾
                    Historylab.SelectionStart = Historylab.TextLength;
                    Historylab.SelectionLength = 0;

                    Historylab.SelectionColor = Color.Blue;
                    Historylab.AppendText("重连中..." + "\n");
                    return System.Threading.Tasks.Task.CompletedTask;
                };

                _connection.Reconnected += (id) =>
                {
                    // 移动光标到文本末尾
                    Historylab.SelectionStart = Historylab.TextLength;
                    Historylab.SelectionLength = 0;

                    Historylab.SelectionColor = Color.Blue;
                    Historylab.AppendText("重连成功！" + "\n");
                    return System.Threading.Tasks.Task.CompletedTask;
                };

                await _connection.StartAsync();
                // 移动光标到文本末尾
                Historylab.SelectionStart = Historylab.TextLength;
                Historylab.SelectionLength = 0;

                Historylab.SelectionColor = Color.Blue;
                Historylab.AppendText("连接成功！" + "\n");
            }
            catch (Exception ex)
            {
                // 移动光标到文本末尾
                Historylab.SelectionStart = Historylab.TextLength;
                Historylab.SelectionLength = 0;

                Historylab.SelectionColor = Color.Blue;
                Historylab.AppendText("连接失败：" + ex.Message + "\n");
            }
        }

        private async void button2_Click(object sender, EventArgs e)
        {
            if (_connection != null)
            {
                await _connection.StopAsync();
                await _connection.DisposeAsync();
                // 移动光标到文本末尾
                Historylab.SelectionStart = Historylab.TextLength;
                Historylab.SelectionLength = 0;

                Historylab.SelectionColor = Color.Blue;
                Historylab.AppendText("断开连接！" + "\n");
            }
        }

        private async void SendMsg_Click(object sender, EventArgs e)
        {
            if (_connection == null || _connection.State != HubConnectionState.Connected)
            {
                // 移动光标到文本末尾
                Historylab.SelectionStart = Historylab.TextLength;
                Historylab.SelectionLength = 0;

                Historylab.SelectionColor = Color.Blue;
                Historylab.AppendText("请先连接！" + "\n");
                return;
            }

            try
            {
                var method = MethodTxt.Text.Trim();
                var paramText = ParamsTxt.Text.Trim();

                object[] parameters = string.IsNullOrWhiteSpace(paramText)
                    ? Array.Empty<object>()
                    : JsonSerializer.Deserialize<object[]>(paramText);
                // 移动光标到文本末尾
                Historylab.SelectionStart = Historylab.TextLength;
                Historylab.SelectionLength = 0;

                Historylab.SelectionColor = Color.Red;
                Historylab.AppendText($"Invoke: {method} {paramText}" + "\n");
                await _connection.InvokeCoreAsync(method,parameters);
                
            }
            catch (Exception ex)
            {
                // 移动光标到文本末尾
                Historylab.SelectionStart = Historylab.TextLength;
                Historylab.SelectionLength = 0;

                Historylab.SelectionColor = Color.Blue;
                Historylab.AppendText($"发送失败: {ex.Message}" + "\n");
            }
        }
    }
}