TCPクライアント側

Imports System.Net
Imports System.Text
Public Class Form1
    'サーバーのIPアドレス（または、ホスト名）とポート番号
    Dim strIpAddr As String = "localhost"
    Dim intPort As Integer = 60000

    'ソケット
    Dim mTcpClient As Sockets.TcpClient
    'ソケットストリーム
    Dim mNetStream As Sockets.NetworkStream
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        'ソケット生成
        mTcpClient = New Sockets.TcpClient
        'ソケット接続
        mTcpClient.Connect(strIpAddr, intPort)
        'ソケットストリーム取得
        mNetStream = mTcpClient.GetStream()
    End Sub

    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
        'ソケットクローズ
        mNetStream.Close()
        mTcpClient.Close()
    End Sub

    Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
        Try
            '送信文字列をバイト配列変換
            Dim enc As Encoding = Encoding.GetEncoding("SHIFT-JIS")
            '最後尾にCR
            Dim data As Byte() = enc.GetBytes(Me.TextBox1.Text.Trim & ControlChars.Cr)
            Me.TextBox1.Text = ""

            'ソケット送信
            mNetStream.Write(data, 0, data.Count)

            'サーバからの応答を受信
            Dim bytRead As Byte() = New Byte(255) {}
            Dim intBytes As Integer = mNetStream.Read(bytRead, 0, bytRead.Length)

            '受信したデータを文字列に変換
            Dim resMsg As String = enc.GetString(bytRead, 0, intBytes)
            '末尾の\rを削除し表示
            Me.TextBox2.Text = resMsg.TrimEnd(ControlChars.Cr)

        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try
    End Sub
End Class