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プロセス間通信(SendMessage)

Imports System.Runtime.InteropServices



Public Class FomSendMessage

    'COPYDATASTRUCT構造体

    Public Structure COPYDATASTRUCT

        Public dwData As Int32   '送信するビット値

        Public cbData As Int32        'lpDataのバイト数

        Public lpData As String     '送信するデータへのポインタ(0も可能)

    End Structure



    Public Const WM_COPYDATA As Int32 = &H4A

    Public Const WM_USER As Int32 = &H400



    "user32.dll", SetLastError:=True, CharSet:=CharSet.Auto)> _

    Private Shared Function FindWindow( _

         ByVal lpClassName As String, _

         ByVal lpWindowName As String) As IntPtr

    End Function



    "user32.dll", SetLastError:=True, CharSet:=CharSet.Auto)> _

     Public Shared Function SendMessage( _

                           ByVal hWnd As IntPtr, _

                           ByVal wMsg As Int32, _

                           ByVal wParam As Int32, _

                           ByVal lParam As Int32) As Integer

    End Function



    "user32.dll", SetLastError:=True, CharSet:=CharSet.Auto)> _

    Public Shared Function SendMessage( _

                            ByVal hWnd As IntPtr, _

                            ByVal wMsg As Int32, _

                            ByVal wParam As Int32, _

                            ByRef lParam As COPYDATASTRUCT) As Integer

    End Function



    '送信ボタン押下

    Private Sub butSend_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles butSend.Click

        Dim result As Int32 = 0



        '相手のウィンドウハンドルを取得します

        Dim hWnd As Int32 = FindWindow(Nothing, txtName.Text)

        If hWnd = 0 Then

            'ハンドルが取得できなかった

            MessageBox.Show("相手Windowのハンドルが取得できません")

            Return

        End If





        '文字列メッセージを送信します

        If txtMessage.Text <> String.Empty Then

            '送信データをByte配列に格納

            Dim bytearry() As Byte = System.Text.Encoding.Default.GetBytes(txtMessage.Text)

            Dim len As Int32 = bytearry.Length

            Dim cds As COPYDATASTRUCT

            cds.dwData = 0        '使用しない

            cds.lpData = txtMessage.Text 'テキストのポインターをセット

            cds.cbData = len + 1     '長さをセット

            '文字列を送る

            result = SendMessage(hWnd, WM_COPYDATA, 0, cds)

        End If



        '数値メッセージを送信します

        If txtInt1.Text <> String.Empty And txtInt2.Text <> String.Empty Then

            Dim int1 As Int32 = 0

            Dim int2 As Int32 = 0

            Try

                '数値に正しく変換出来るか？

                int1 = CType(txtInt1.Text, Int32)

                int2 = CType(txtInt2.Text, Int32)

            Catch

                MessageBox.Show("入力された数値が正しく有りません")

                Return

            End Try






            '数値を送る

            result = SendMessage(hWnd, WM_USER, int1, int2)

        End If

    End Sub

End Class