.Net Framework 平台下创建WinForm窗体SignalR客户端

 partial class Form1
    {
        /// <summary>
        /// 必需的设计器变量。
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// 清理所有正在使用的资源。
        /// </summary>
        /// <param name="disposing">如果应释放托管资源，为 true；否则为 false。</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows 窗体设计器生成的代码

        /// <summary>
        /// 设计器支持所需的方法 - 不要修改
        /// 使用代码编辑器修改此方法的内容。
        /// </summary>
        private void InitializeComponent()
        {
            this.addressTextBox = new System.Windows.Forms.TextBox();
            this.connectButton = new System.Windows.Forms.Button();
            this.label1 = new System.Windows.Forms.Label();
            this.messagesList = new System.Windows.Forms.ListBox();
            this.sendButton = new System.Windows.Forms.Button();
            this.messageTextBox = new System.Windows.Forms.TextBox();
            this.disconnectButton = new System.Windows.Forms.Button();
            this.SuspendLayout();
            // 
            // addressTextBox
            // 
            this.addressTextBox.Anchor = ((System.Windows.Forms.AnchorStyles)(((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Left)
            | System.Windows.Forms.AnchorStyles.Right)));
            this.addressTextBox.Location = new System.Drawing.Point(66, 10);
            this.addressTextBox.Name = "addressTextBox";
            this.addressTextBox.Size = new System.Drawing.Size(521, 20);
            this.addressTextBox.TabIndex = 0;
            this.addressTextBox.Enter += new System.EventHandler(this.addressTextBox_Enter);
            // 
            // connectButton
            // 
            this.connectButton.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Right)));
            this.connectButton.Location = new System.Drawing.Point(593, 8);
            this.connectButton.Name = "connectButton";
            this.connectButton.Size = new System.Drawing.Size(75, 23);
            this.connectButton.TabIndex = 1;
            this.connectButton.Text = "Connect";
            this.connectButton.UseVisualStyleBackColor = true;
            this.connectButton.Click += new System.EventHandler(this.connectButton_Click);
            // 
            // label1
            // 
            this.label1.AutoSize = true;
            this.label1.Location = new System.Drawing.Point(12, 13);
            this.label1.Name = "label1";
            this.label1.Size = new System.Drawing.Size(48, 13);
            this.label1.TabIndex = 2;
            this.label1.Text = "Address:";
            // 
            // messagesList
            // 
            this.messagesList.Anchor = ((System.Windows.Forms.AnchorStyles)((((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Bottom)
            | System.Windows.Forms.AnchorStyles.Left)
            | System.Windows.Forms.AnchorStyles.Right)));
            this.messagesList.DrawMode = System.Windows.Forms.DrawMode.OwnerDrawFixed;
            this.messagesList.FormattingEnabled = true;
            this.messagesList.Location = new System.Drawing.Point(15, 36);
            this.messagesList.Name = "messagesList";
            this.messagesList.SelectionMode = System.Windows.Forms.SelectionMode.None;
            this.messagesList.Size = new System.Drawing.Size(734, 485);
            this.messagesList.TabIndex = 3;
            this.messagesList.DrawItem += new System.Windows.Forms.DrawItemEventHandler(this.messagesList_DrawItem);
            // 
            // sendButton
            // 
            this.sendButton.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Right)));
            this.sendButton.Enabled = false;
            this.sendButton.Location = new System.Drawing.Point(674, 532);
            this.sendButton.Name = "sendButton";
            this.sendButton.Size = new System.Drawing.Size(75, 23);
            this.sendButton.TabIndex = 5;
            this.sendButton.Text = "Send";
            this.sendButton.UseVisualStyleBackColor = true;
            this.sendButton.Click += new System.EventHandler(this.sendButton_Click);
            // 
            // messageTextBox
            // 
            this.messageTextBox.Anchor = ((System.Windows.Forms.AnchorStyles)(((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Left)
            | System.Windows.Forms.AnchorStyles.Right)));
            this.messageTextBox.Enabled = false;
            this.messageTextBox.Location = new System.Drawing.Point(15, 534);
            this.messageTextBox.Name = "messageTextBox";
            this.messageTextBox.Size = new System.Drawing.Size(653, 20);
            this.messageTextBox.TabIndex = 4;
            this.messageTextBox.Enter += new System.EventHandler(this.messageTextBox_Enter);
            // 
            // disconnectButton
            // 
            this.disconnectButton.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Right)));
            this.disconnectButton.Enabled = false;
            this.disconnectButton.Location = new System.Drawing.Point(674, 8);
            this.disconnectButton.Name = "disconnectButton";
            this.disconnectButton.Size = new System.Drawing.Size(75, 23);
            this.disconnectButton.TabIndex = 6;
            this.disconnectButton.Text = "Disconnect";
            this.disconnectButton.UseVisualStyleBackColor = true;
            this.disconnectButton.Click += new System.EventHandler(this.disconnectButton_Click);
            // 
            // ChatForm
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(761, 566);
            this.Controls.Add(this.disconnectButton);
            this.Controls.Add(this.sendButton);
            this.Controls.Add(this.messageTextBox);
            this.Controls.Add(this.messagesList);
            this.Controls.Add(this.label1);
            this.Controls.Add(this.connectButton);
            this.Controls.Add(this.addressTextBox);
            this.Name = "ChatForm";
            this.Text = "SignalR Chat Sample";
            this.Load += new System.EventHandler(this.ChatForm_Load);
            this.ResumeLayout(false);
            this.PerformLayout();
        }
        private System.Windows.Forms.TextBox addressTextBox;
        private System.Windows.Forms.Button connectButton;
        private System.Windows.Forms.Label label1;
        private System.Windows.Forms.ListBox messagesList;
        private System.Windows.Forms.Button sendButton;
        private System.Windows.Forms.TextBox messageTextBox;
        private System.Windows.Forms.Button disconnectButton;
        #endregion
    }

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


        private void ChatForm_Load(object sender, EventArgs e)
        {
            addressTextBox.Focus();
        }

        private void addressTextBox_Enter(object sender, EventArgs e)
        {
            AcceptButton = connectButton;
        }

        private async void connectButton_Click(object sender, EventArgs e)
        {
            UpdateState(connected: false);

            _connection = new HubConnectionBuilder()
                .WithUrl(addressTextBox.Text)
                .Build();

            _connection.On<string, string>("myMessage", (s1, s2) => OnSend(s1, s2));

            Log(Color.Gray, "Starting connection...");
            try
            {
                await _connection.StartAsync();
            }
            catch (Exception ex)
            {
                Log(Color.Red, ex.ToString());
                return;
            }

            Log(Color.Gray, "Connection established.");

            UpdateState(connected: true);

            messageTextBox.Focus();
        }

        private async void disconnectButton_Click(object sender, EventArgs e)
        {
            Log(Color.Gray, "Stopping connection...");
            try
            {
                await _connection.StopAsync();
            }
            catch (Exception ex)
            {
                Log(Color.Red, ex.ToString());
            }

            Log(Color.Gray, "Connection terminated.");

            UpdateState(connected: false);
        }

        private void messageTextBox_Enter(object sender, EventArgs e)
        {
            AcceptButton = sendButton;
        }

        private async void sendButton_Click(object sender, EventArgs e)
        {
            try
            {
                await _connection.InvokeAsync("Send", "WinFormsApp", messageTextBox.Text);
            }
            catch (Exception ex)
            {
                Log(Color.Red, ex.ToString());
            }
        }

        private void UpdateState(bool connected)
        {
            disconnectButton.Enabled = connected;
            connectButton.Enabled = !connected;
            addressTextBox.Enabled = !connected;

            messageTextBox.Enabled = connected;
            sendButton.Enabled = connected;
        }

        private void OnSend(string name, string message)
        {
            Log(Color.Black, name + ": " + message);
        }

        private void Log(Color color, string message)
        {
            Action callback = () =>
            {
                messagesList.Items.Add(new LogMessage(color, message));
            };

            Invoke(callback);
        }

        private class LogMessage
        {
            public Color MessageColor { get; }

            public string Content { get; }

            public LogMessage(Color messageColor, string content)
            {
                MessageColor = messageColor;
                Content = content;
            }
        }

        private void messagesList_DrawItem(object sender, DrawItemEventArgs e)
        {
            var message = (LogMessage)messagesList.Items[e.Index];
            e.Graphics.DrawString(
                message.Content,
                messagesList.Font,
                new SolidBrush(message.MessageColor),
                e.Bounds);
        }
    }