{"Only TimeSpan objects can be serialized by MySqlTimeSpan"} 与 VB.NET

Question

我有 form2 可以在我的 table 中添加新数据然后我得到这个错误：

 {"Only TimeSpan objects can be serialized by MySqlTimeSpan"}

当我删除这部分代码时它起作用了：

 cm.Parameters.Add(New MySqlParameter("@Time_Operation",  MySqlDbType.Time)).Value = Time_OperationTextBox.Text
    cm.Parameters.Add(New MySqlParameter("@Start_Time", MySqlDbType.Time)).Value = Start_TimeTextBox.Text
    cm.Parameters.Add(New MySqlParameter("@End_Time", MySqlDbType.Time)).Value = End_TimeTextBox.Text

这意味着日期时间工作正常，但我将它们作为

设置的那三个参数存在问题

 Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

    Dim str As String = "Server=localhost;Port=3306;Database=springdb;Uid=root;Pwd=2342"


    Using con As New MySqlConnection(str)

        Dim query As String = "Insert Into springdata (full_name,rfid_tag,spring_size,operation_time,Date_Operation,
                                    Time_Operation,Start_Time,End_Time,Qty_Needed) values
                                    (@full_name, @rfid_tag, @spring_size, @operation_time,
                                    @Date_Operation, @Time_Operation, @Start_Time, @End_Time, @Qty_Needed) 
                                      " 'Note:TextBox3 is the RFID number come from RFID arduino

        Dim cm As New MySqlCommand(query, con)
        cm.Parameters.Add(New MySqlParameter("@full_name", MySqlDbType.LongText)).Value = TextBox1.Text
        cm.Parameters.Add(New MySqlParameter("@rfid_tag", MySqlDbType.LongText)).Value = TextBox2.Text
        cm.Parameters.Add(New MySqlParameter("@spring_size", MySqlDbType.MediumText)).Value = TextBox3.Text
        cm.Parameters.Add(New MySqlParameter("@operation_time", MySqlDbType.DateTime)).Value = DateTimePicker1.Value
        cm.Parameters.Add(New MySqlParameter("@Date_Operation", MySqlDbType.Date)).Value = DateTimePicker2.Value
        cm.Parameters.Add(New MySqlParameter("@Time_Operation", MySqlDbType.Time)).Value = Time_OperationTextBox.Text
        cm.Parameters.Add(New MySqlParameter("@Start_Time", MySqlDbType.Time)).Value = Start_TimeTextBox.Text
        cm.Parameters.Add(New MySqlParameter("@End_Time", MySqlDbType.Time)).Value = End_TimeTextBox.Text
        cm.Parameters.Add(New MySqlParameter("@Qty_Needed", MySqlDbType.Int32)).Value = TextBox7.Text


        con.Open()

        cm.ExecuteNonQuery()

        MessageBox.Show("success")
    End Using

End Sub

Answer 1

我是这样想出来的：

        Dim cm As New MySqlCommand(("Insert Into springdata (full_name,rfid_tag,spring_size,operation_time,Date_Operation,
                                    Time_Operation,Start_Time,End_Time,Qty_Needed )  Values ('" & TextBox1.Text & "', '" & TextBox2.Text & "',
                                    '" & ComboBox1.Text & "', '" & DateTimePicker1.Value.ToString("yyyy-MM-dd HH:mm:ss") & "',
                                     '" & DateTimePicker2.Value.ToString("yyyy-MM-dd") & "', '" & Time_OperationTextBox.Text & "', 
                                      '" & Start_TimeTextBox.Text & "', '" & End_TimeTextBox.Text & "', 
                                      '" & TextBox7.Text & "')"), con)

不幸的是我无法用timespan,parse解决它:-)

Answer 2

错误消息告诉您您给参数值的类型是 string，但是您的 mySQL 方法需要一个 TimeSpan - 您需要解析作为TimeSpan输入到文本框中的字符串，然后将生成的TimeSpan变量而不是字符串传递给mySQL参数。

TimeSpan.Parse() 方法接受一个字符串作为输入，然后使用它从字符串中读取的值输出一个 TimeSpan 对象。

cm.Parameters.Add(New MySqlParameter("@Time_Operation",  MySqlDbType.Time)).Value = TimeSpan.Parse(Time_OperationTextBox.Text)
cm.Parameters.Add(New MySqlParameter("@Start_Time", MySqlDbType.Time)).Value = TimeSpan.Parse(Start_TimeTextBox.Text)
cm.Parameters.Add(New MySqlParameter("@End_Time", MySqlDbType.Time)).Value = TimeSpan.Parse(End_TimeTextBox.Text)

当然，在此之前，您必须确保您的用户在文本框中输入的内容采用 TimeSpan 代码可以理解的有效格式（有关可接受格式的信息，请参阅下面的文档 link）。

文档：https://docs.microsoft.com/en-us/dotnet/api/system.timespan.parse?view=netframework-4.7.2

{"Only TimeSpan objects can be serialized by MySqlTimeSpan"} 与 VB.NET

{"Only TimeSpan objects can be serialized by MySqlTimeSpan"} with VB.NET

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