单击更新

Question

当我单击Update按钮时，将调用以下功能，但数据库未更新。语法是正确的，但我无法弄清楚我缺少什么。有什么建议吗？

Private Sub UpDateRecord()
    Dim connString As String = ConfigurationManager.ConnectionStrings("dbx").ConnectionString
    Dim cmdString As String = "UPDATE hpn " & _
                                  "SET " &_ 
                                      "Day = @Day, " & _ 
                                      "FullName =@FullName, " & _  
                                      "Balance = @Balance, " & _  
                                      "Deposit = @Deposit, " & _  
                                      "Withdraw = @Withdraw, " & _ 
                                      "CashIn = @CashIn, " & _ 
                                      "CashOut = @CashOut, " & _ 
                                      "Spend = @Spend, " & _ 
                                      "Total = @Total " & _
                                  "WHERE ID = @ID"
    Using conn As New OleDbConnection(connString)
        conn.Open() 'conn.Open() before creating OleDbCommand Obj
        Using cmd As New OleDbCommand(cmdString, conn)
            cmd.Parameters.AddWithValue("@Day", TextBox1.Text)
            cmd.Parameters.AddWithValue("@FullName", TextBox2.Text)
            cmd.Parameters.AddWithValue("@Balance", TextBox3.Text)
            cmd.Parameters.AddWithValue("@Deposit", TextBox4.Text)
            cmd.Parameters.AddWithValue("@Withdraw", TextBox5.Text)
            cmd.Parameters.AddWithValue("@CashIn", TextBox6.Text)
            cmd.Parameters.AddWithValue("@CashOut", TextBox7.Text)
            cmd.Parameters.AddWithValue("@Spend", TextBox8.Text)
            cmd.Parameters.AddWithValue("@Total", TextBox9.Text)
            cmd.Parameters.AddWithValue("@ID", Me.ID)
        End Using
    End Using
End Sub

Answer 1

如果您不调用OleDbCommand.ExecuteNonQuery()，应该如何更新数据库？

固定代码：

Using conn As New OleDbConnection(connString)
    conn.Open() 'conn.Open() before creating OleDbCommand Obj
    Using cmd As New OleDbCommand(cmdString, conn)
        cmd.Parameters.AddWithValue("@Day", TextBox1.Text)
        cmd.Parameters.AddWithValue("@FullName", TextBox2.Text)
        cmd.Parameters.AddWithValue("@Balance", TextBox3.Text)
        cmd.Parameters.AddWithValue("@Deposit", TextBox4.Text)
        cmd.Parameters.AddWithValue("@Withdraw", TextBox5.Text)
        cmd.Parameters.AddWithValue("@CashIn", TextBox6.Text)
        cmd.Parameters.AddWithValue("@CashOut", TextBox7.Text)
        cmd.Parameters.AddWithValue("@Spend", TextBox8.Text)
        cmd.Parameters.AddWithValue("@Total", TextBox9.Text)
        cmd.Parameters.AddWithValue("@ID", Me.ID)
        cmd.ExecuteNonQuery() 'THIS IS THE LINE YOU WERE MISSING
    End Using
    conn.Close() 'YOU FORGOT TO CLOSE THE CONNECTION
End Using

这段代码充满了错误：

• 最好在右侧Using内打开连接
• 您没有调用OleDbCommand.ExecuteNonQuery()，因此所有参数均已设置，但未执行查询。
• 您没有关闭连接。