Question

我正在为数据库使用Access。表乘客具有以下我似乎找不到问题所在。有人可以帮帮我吗

Passenger Number(Auto Number)
FirstName (short text)
LastName (short text)
Initials (short text)
ID_number (short text)
Gender (short text)
Date_of_Birth (Date/Time)
Cell_Number (short text)
Street_Number (number)
Street_Name (short text)
Postal_Code  (number)

//这些是我的变量

        string name = txtFirstName.Text;
        string surname = textBox3.Text;
        string initials = textBox2.Text;
        string id = textBox6.Text;
        string gender = comboBox1.SelectedItem.ToString();
        string dest = cmbDestination.SelectedValue.ToString();
        string num =textBox9.Text;
        string snum = textBox8.Text;
        string sname = textBox7.Text;
        string pcode = comboBox2.SelectedItem.ToString();
        string date = dateTimePicker1.Text;

//这是我的代码，应该向表乘客添加新记录，但我不断收到错误消息

        try
            {
               using (OleDbConnection connect = new 
               OleDbConnection(@"Provider=Microsoft.ACE.OLEDB.12.0;Data 
               Source=" + Application.StartupPath + "\\Database3.accdb"))
               {

                   OleDbCommand cmd = new OleDbCommand("INSERT INTO 
                   Passengers ([FirstName],[LastName],[Initials] , 
                   [ID_number],[Gender],[Date_Of_Birth],[Cell_Number], 
                   [Street_Number], [Street_Name],[Postal_Code]) VALUES 
                   (?,?,?,?,?,?,?,?,?,?)", connect);
                    cmd.Connection = connect;

                    cmd.Parameters.AddWithValue("@FirstName", name);
                    cmd.Parameters.AddWithValue("@LastName", surname);
                    cmd.Parameters.AddWithValue("@Initials", initials);
                    cmd.Parameters.AddWithValue("@ID_number", id);
                    cmd.Parameters.AddWithValue("@Gender", gender);
                    cmd.Parameters.AddWithValue("@Date_Of_Birth", date);
                    cmd.Parameters.AddWithValue("@Cell_Number", num);
                    cmd.Parameters.AddWithValue("@Street_Number", snum);
                    cmd.Parameters.AddWithValue("@Street_Name", sname);
                    cmd.Parameters.AddWithValue("@Postal_Code", pcode);


                    connect.Open();
                    cmd.ExecuteNonQuery();

                    OleDbDataAdapter adapt = new OleDbDataAdapter("SELECT * 
                    FROM Passengers", connect);
                    MessageBox.Show("Seat successfully booked for 
                    passenger!");
                    Console.Beep(659, 125); Console.Beep(659, 125); 
                    Console.Beep(659, 125);

                    this.Close();
                    connect.Close();


                }
            }
            catch(Exception ex)
            {
                MessageBox.Show(ex.Message);
            }

Answer 1

示例代码中存在多个列值分配问题，在这种情况下，您要将string值传递给类型为number或date的列，这会导致数据类型不匹配例外。

您应该使用AddWithValue来指定适当的数据类型和值，而不是像所有示例那样使用OleDbCommand.Parameters.Add()：

// note: use DateTime.ParseExact for specific date formatting
cmd.Parameters.Add("@Date_Of_Birth", OleDbType.Date).Value = DateTime.Parse(dateTimePicker1.Text);

cmd.Parameters.Add("@Street_Number", OleDbType.Integer).Value = int.Parse(textBox8.Text);
cmd.Parameters.Add("@Postal_Code", OleDbType.Integer).Value = int.Parse(comboBox2.SelectedItem.ToString());

编辑：

对于DateTimePicker控件，您可以使用DateTime类型的Value属性：

cmd.Parameters.Add("@Date_Of_Birth", OleDbType.Date).Value = dateTimePicker1.Value;

参考：ADO.NET OLE DB Data Type Mappings

我不断收到此错误，条件表达式中的数据类型不匹配。我不知道为什么

1 个答案: