尝试插入Access数据库时，条件表达式错误中的数据类型不匹配

Question

我正在尝试将用户在Winform上输入的值插入到以下Access表中：

C＃代码是：

    OleDbCommand oleCmd = new OleDbCommand("INSERT INTO Projects (projectTitle,partyID,receiveDate,dueDate, projectTypeID, pages, "+
        "lines, words, prepay, cost, settled,projectComment)"
    + " VALUES (@projectTitle,@partyID,@receiveDate,@dueDate,@projectTypeID,@pages, @lines, @words, @prepay, @cost, @settled, @projectComment)", conn);


    PersianCalendar p=new PersianCalendar();
    DateTime thisDate=DateTime.Now;
    oleCmd.Parameters.Add("@projectTitle", OleDbType.VarChar).Value = txtProjectTitle.Text;
    oleCmd.Parameters.Add("@partyID", OleDbType.Numeric).Value = Convert.ToInt32(comboProjectType.SelectedValue.ToString());
    oleCmd.Parameters.AddWithValue("@receiveDate", string.Format( "{0}, {1}/{2}/{3} {4}:{5}:{6}",
        p.GetDayOfWeek(thisDate), p.GetYear(thisDate),p.GetMonth(thisDate),p.GetDayOfMonth(thisDate), p.GetHour(thisDate),p.GetMinute(thisDate),p.GetSecond(thisDate))) ;                        
    oleCmd.Parameters.Add("@dueDate", OleDbType.VarChar).Value = comboDay.Text + "/" + comboMonth.Text + "/" + comboYear.Text;          
    oleCmd.Parameters.Add("@projectTypeID", OleDbType.Numeric).Value = Convert.ToInt32(comboContractParty.SelectedValue.ToString());
    oleCmd.Parameters.AddWithValue("@pages", Convert.ToInt32(txtPages.Text));
    oleCmd.Parameters.AddWithValue("@lines", Convert.ToInt32(txtLines.Text));
    oleCmd.Parameters.AddWithValue("@words", Convert.ToInt32(txtWords.Text));
    oleCmd.Parameters.AddWithValue("@cost", Convert.ToDouble(txtWholeProjCost.Text));
    oleCmd.Parameters.AddWithValue("@prepay", Convert.ToDouble(txtPrePay.Text));
    oleCmd.Parameters.AddWithValue("@settled", chkSettled.CheckState); 
    oleCmd.Parameters.Add("@projectComment", OleDbType.VarChar).Value = txtComment.Text.ToString();
    try
    {
        conn.Open();
        oleCmd.ExecuteNonQuery();
        conn.Close();
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.ToString());
        return;
    }

例外说：

  

标准表达式中的数据类型不匹配。

我重新检查了类型，但不知道错误的来源。

Answer 1

receiveDate和dueDate在数据库中定义为DateTime，但您将文本（字符串）传递给参数：

oleCmd.Parameters.AddWithValue("@receiveDate", string.Format(... 

oleCmd.Parameters.Add("@dueDate", OleDbType.VarChar).Value = ...

传递实际的DateTime vars，它应该有效。由于日期是碎片，我会先创建它们，以便进行测试：

// why not use thisDate rather than chopping it up to recombine?
DateTime recDate = New DateTime(p.Getyear(thisDate)...);

// personally, I might use a DateTimePicker rather than 3 CBOs
DateTime dueDate  = New DateTime(ConvertToInt32(comboYear.Text), ...

然后将它们作为参数传递给他们。如果您使用Add指定OleDbType.Date：

oleCmd.Parameters.AddWithValue("@receiveDate", recDate); 
...
oleCmd.Parameters.AddWithValue("@dueDate", dueDate);