[سؤال] ماهو كود منع ظهور نافذة باسم محدد لكن...

كود :

Private Sub listBox1_MouseDoubleClick(sender As Object, e As MouseEventArgs)

    For Each f As Form In Application.OpenForms

        If Break(f) Then

            f.Activate()

            Exit For

        End If

    Next

End Sub

Private Function Break(form As Form) As Boolean

    For Each ctrl As Control In form.Controls

        If TypeOf ctrl Is Label AndAlso ctrl.Text = listBox1.Text Then

            Return True

        End If

    Next

    Return False

End Function

كود :

Private Sub ListBox1_MouseDoubleClick(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles ListBox1.MouseDoubleClick

        ' MsgBox(ListBox1.Text)

        Dim chat As New chat

        Dim gip As New SqlCommand("select uname,myip from tusers where uname='" & ListBox1.Text & "'", conn)

        If conn.State = ConnectionState.Closed Then

            conn.Open()

        End If

        Dim dr As SqlDataReader = gip.ExecuteReader

        If dr.Read Then

            Try

                chat.frindname.Text = ListBox1.Text

                frindip = dr.Item("myip")

                chat.Show()

            Catch ex As Exception

                MsgBox("هذا العضو لم يسجل دخوله ليتم تحديث معلومات الاتصال به", MsgBoxStyle.Critical, "")

            End Try

        End If

    End Sub

كود :

Private Sub ListBox1_MouseDoubleClick(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles ListBox1.MouseDoubleClick

        ' MsgBox(ListBox1.Text)

    dim stop as Boolean

    For Each f As Form In Application.OpenForms

        If Break(f) Then

            f.Activate()

            stop = true

            Exit For

        End If

    Next

    if stop then exit sub

        Dim chat As New chat

        Dim gip As New SqlCommand("select uname,myip from tusers where uname='" & ListBox1.Text & "'", conn)

        If conn.State = ConnectionState.Closed Then

            conn.Open()

        End If

        Dim dr As SqlDataReader = gip.ExecuteReader

        If dr.Read Then

            Try

                chat.frindname.Text = ListBox1.Text

                frindip = dr.Item("myip")

                chat.Show()

            Catch ex As Exception

                MsgBox("هذا العضو لم يسجل دخوله ليتم تحديث معلومات الاتصال به", MsgBoxStyle.Critical, "")

            End Try

        End If

    End Sub

 Private Function Break(form As Form) As Boolean

    For Each ctrl As Control In form.Controls

        If TypeOf ctrl Is Label AndAlso ctrl.Text = listBox1.Text Then

            Return True

        End If

    Next

    Return False

End Function