我正在尝试更新数据，但它不起作用

Question

我制作了一个程序来保存和更新 Access 数据库中的数据，我可以保存和读取数据，我也可以更新，但问题是当我尝试更新数据时，它会进入第二个条件“数据未更新”。我已经添加了我的代码，如果有任何错误，请帮助我解决它。

    using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.Data;
    using System.Drawing;
    using System.Linq;
    using System.Text;
    using System.Threading.Tasks;
    using System.Windows.Forms;
    using System.Data.SqlClient;
    using System.Data.OleDb;
    
    namespace qasimpos
    {
        public partial class Form9 : Form
        {
            string connectionString = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=|DataDirectory|\pos.accdb;Persist Security Info=True";
            string nname, ddate, ccompany, pparty, oorder, kkg, PpCS, ppprice, ccprice, wwprice, rrprice, bbilln, qquantity;
            
    
            private void btnclose_Click(object sender, EventArgs e)
            {
                this.Close();
            }
    
            private void btnup_Click(object sender, EventArgs e)
            {
                nname = textBox1.Text;
                ddate = textBox2.Text;
                ccompany = textBox3.Text;
                pparty = textBox4.Text;
                oorder = textBox5.Text;
                kkg = textBox6.Text;
                PpCS = textBox7.Text;
                ppprice = textBox8.Text;
                ccprice = textBox9.Text;
                wwprice = textBox10.Text;
                rrprice = textBox11.Text;
                bbilln = textBox12.Text;
                qquantity = textBox13.Text;
    
                //SqlConnection connection = new SqlConnection(connectionString);
                OleDbConnection connection = new OleDbConnection(connectionString);
                connection.Open();
                try
                {
                    string query = "UPDATE prod SET tareekh=@tareekh,company=@company,party=@party,hukam=@hukam,kg=@kg,PCS=@PCS,pprice=@pprice,cprice=@cprice,wprice=@wprice,rprice=@rprice,billn=@billn,quantity=@quantity WHERE namee=@namee";
                    //SqlCommand cmmd = new SqlCommand(query, connection);
                    OleDbCommand cmmd = new OleDbCommand(query, connection);
                    cmmd.Parameters.AddWithValue("@namee", nname);
                    cmmd.Parameters.AddWithValue("@tareekh", ddate);
                    cmmd.Parameters.AddWithValue("@company", ccompany);
                    cmmd.Parameters.AddWithValue("@party", pparty);
                    cmmd.Parameters.AddWithValue("@hukam", oorder);
                    cmmd.Parameters.AddWithValue("@kg", kkg);
                    cmmd.Parameters.AddWithValue("@PCS", PpCS);
                    cmmd.Parameters.AddWithValue("@pprice", ppprice);
                    cmmd.Parameters.AddWithValue("@cprice", ccprice);
                    cmmd.Parameters.AddWithValue("@wprice", wwprice);
                    cmmd.Parameters.AddWithValue("@rprice", rrprice);
                    cmmd.Parameters.AddWithValue("@billn", bbilln);
                    cmmd.Parameters.AddWithValue("@quantity", qquantity);
    
                    int result = cmmd.ExecuteNonQuery();
                    if (result > 0)
                    {
                        MessageBox.Show("Data Updated Successfully ");
                        this.Close();
                        
                    }
                    else
                    {
                        MessageBox.Show("Data Not Updated");
                    }
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }
                finally
                {
                    connection.Close();
                }
    
    
            }
    
            private void textBox12_TextChanged(object sender, EventArgs e)
            {
    
            }
    
            private void Form9_Load(object sender, EventArgs e)
            {
                textBox1.Text = nname;
                textBox2.Text = ddate;
                textBox3.Text = ccompany;
                textBox4.Text = pparty;
                textBox5.Text = oorder;
                textBox6.Text = kkg;
                textBox7.Text = PpCS;
                textBox8.Text = ppprice;
                textBox9.Text = ccprice;
                textBox10.Text = wwprice;
                textBox11.Text = rrprice;
                textBox12.Text = bbilln;
                textBox13.Text = qquantity;
            }
    
            public Form9(string namee,string tareekh,string company,string party,string hukam,string kg,string PCS,string pprice,string cprice,string wprice,string rprice,string billn,string quantity)
            {
                InitializeComponent();
                nname = namee;
                ddate = tareekh;
                ccompany = company;
                pparty = party;
                oorder = hukam;
                kkg = kg;
                PpCS = PCS;
                ppprice = pprice;
                ccprice = cprice;
                wwprice = wprice;
                rrprice = rprice;
                bbilln = billn;
                qquantity = quantity;
            }
        }
    } 

Answer 1

参数应与查询中提到的相同。

请直接从documentation找到以下内容

OLE DB .NET 提供程序不支持传递命名参数 SQL 语句或存储过程的参数 当 CommandType 设置为 Text 时的 OleDbCommand。在这种情况下， 必须使用问号 (?) 占位符。例如：选择 * 从 客户 WHERE CustomerID = ?因此，其中的顺序 OleDbParameter 对象必须添加到 OleDbParameterCollection 直接对应问号占位符的位置 用于命令文本中的参数。