Oledb No Value Given for an or more required parameters VB.NET

Question

谁能告诉我我的代码有什么问题？我在这里是一个完全的新手，这是我很长一段时间以来第一次尝试写东西，

下面的代码应该更新访问数据库中的两个字段

Private Sub TestButton_Click(sender As Object, e As EventArgs) Handles TestButton.Click
    'connects application to database
    Dim ConnString As String = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\DatabasePath\database.accdb"
    Dim SqlString As String = "update SaintStaff set [StaffHours]=[@CAHours],[RecordedTime]=[@Time] where [StaffName] = " & Label2.Text & ""

    'updates record in  SaintStaff table.
    Using conn As New OleDbConnection(ConnString)
        conn.Open()
        Using cmd As New OleDbCommand(SqlString, conn)
            cmd.CommandType = CommandType.Text
            cmd.Parameters.AddWithValue("[@CAHours]", Label6.Text)
            cmd.Parameters.AddWithValue("[@Time]", Label10.Text)
            cmd.ExecuteNonQuery()
        End Using
        conn.Close()
    End Using
End Sub

我收到以下错误 System.Data.OleDb.OleDbException: 'No value given for one or more required parameters.'

它在每一行突出显示 cmd 文本，我不知道我做错了什么，有人能帮忙吗？

谢谢

Answer 1

MatSnow 和 olivier-jacot-descombes 在评论中回答了这个问题，正确的代码如下

Private Sub TestButton_Click(sender As Object, e As EventArgs) Handles TestButton.Click
    'connects application to database
    Dim ConnString As String = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\DatabasePath\Database.accdb"
    Dim SqlString As String = "update SaintStaff set StaffHours = @CAHours, RecordedTime = @Time where StaffName = @staffname "

    'updates record in  SaintStaff table.
    Using conn As New OleDbConnection(ConnString)
        conn.Open()
        Using cmd As New OleDbCommand(SqlString, conn)
            cmd.CommandType = CommandType.Text
            cmd.Parameters.Add("@CAHours", OleDbType.VarChar).Value = Label6.Text
            cmd.Parameters.Add("@Time", OleDbType.VarChar).Value = Label10.Text
            cmd.Parameters.Add("@Staffname", OleDbType.VarChar).Value = Label2.Text
            cmd.ExecuteNonQuery()
        End Using
        conn.Close()
    End Using
End Sub

Oledb No Value Given for an or more required parameters VB.NET

Oledb No Value Given for one or more required parameters VB.NET

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