谁能帮我把这个放在哪里？这样我使用的变量就不会保存在内存中。我在想我应该把它放在哪里或者什么时候用。
我试过了
myquery.dispose（）
但我觉得我做错了。

Private Sub btnRegister_Click(sender As Object, e As EventArgs) Handles btnRegister.Click
    mysqlConn.Open()
    If TextBox01.Text = "" Or TextBox02.Text = "" Or TextBox04.Text = "" Or TextBox05.Text = "" Or TextBox06.Text = "" Then
        MsgBox("Please fill in all boxes")
        Exit Sub

    Else

        sqlCmd = New Odbc.OdbcCommand
        sqlCmd.Connection = mysqlConn
        sqlCmd.CommandType = CommandType.Text
        sqlCmd.CommandText = "select * from tbl_user where username='" & TextBox05.Text & "' Or email='" & TextBox04.Text & "' "
        dr = sqlCmd.ExecuteReader

        If dr.HasRows Then
            MsgBox("Username or Email already Exist", MsgBoxStyle.Critical)
        Else

            Dim myQuery As String

            myQuery = "INSERT INTO tbl_user(firstname, lastname, email, username, password) VALUES ('" & Replace(Trim(TextBox01.Text), "'", "''") & "', '" & Replace(Trim(TextBox02.Text), "'", "''") & "', '" & Replace(Trim(TextBox04.Text), "'", "''") & "', '" & Replace(Trim(TextBox05.Text), "'", "''") & "', '" & Replace(Trim(TextBox06.Text), "'", "''") & "')"

            sqlCmd = New Odbc.OdbcCommand
            sqlCmd.Connection = mysqlConn
            sqlCmd.CommandText = myQuery

            dr = sqlCmd.ExecuteReader

            MessageBox.Show("You are now register!", "System", MessageBoxButtons.OK)
            Me.Hide()
            frmMenu.Hide()
            frmLogin.Show()

            TextBox01.Text = ""
            TextBox02.Text = ""
            TextBox04.Text = ""
            TextBox05.Text = ""
            TextBox06.Text = ""
        End If
    End If
    mysqlConn.Close()
End Sub