c# - 更新数据库中的信息

Question

我想使用 C# 更新数据库 im 上的用户信息。 这是我的代码，它不起作用，也没有给我任何错误。

protected void Page_Load(object sender, EventArgs e)
{
    lbldisplay.Text = "<b><font color=BLUE>" + "WELLCOME:: " + "</font>" + "<b><font color=white>" + Session["Name"] + "</font>";
    SqlConnection con = new SqlConnection("Data Source=STUDENT-PC;Initial Catalog=webservice_BuyBid;Integrated Security=True");
}
protected void btnLogOut_Click(object sender, EventArgs e)
{
    //this will redirect the page to the home.aspx page.
    Response.Redirect("Home.aspx");
}

protected void btnUpdate_Click(object sender, EventArgs e)
{
    //creating a new connection to the database
    SqlConnection con = new SqlConnection("Data Source=STUDENT-PC;Initial Catalog=BuyBid;Integrated Security=True;Asynchronous Processing=True;");
    con.Open();
    //creates a new sqlcommand to update the buyer's information to the Database.
    SqlCommand cmd = new SqlCommand("UPDATE BUYER SET Name = @Name,Surname = @Surname,Email =@Email,CellNumber =@CellNumber", con);
    con.Open();

    cmd.Parameters.AddWithValue("@Name", txtNameUpdate.Text);
    cmd.Parameters.AddWithValue("@Surname", txtSurnameUpdate.Text);
    cmd.Parameters.AddWithValue("@Email", txtemailUpdate.Text);
    cmd.Parameters.AddWithValue("@CellNumber", txtCellUpdate.Text);

   int rows = cmd.ExecuteNonQuery();
    con.Close();

Answer 1

您的问题是您正在打开一个连接(这是正确的)，但随后您又打开了它。

这就是更新没有发生的原因。此外，您无需在 finally 语句中关闭连接。出于此目的，它不是必需的。

同时你正在执行更新语句，所以请确保你给它一个条件来更新特定的记录。

我已经适本地编辑了您的代码，这应该可以解决您的问题: (久经考验)

---

    protected void btnUpdate_Click(object sender, EventArgs e)
    {
        try
        {
            //creating a new connection to the database
            SqlConnection con = new SqlConnection("Data Source=STUDENT-  PC;Initial Catalog=BuyBid;Integrated Security=True;Asynchronous  Processing=True;");
            con.Open();
            //creates a new sqlcommand to update the buyers information to the   Database.
            SqlCommand cmd = new SqlCommand("UPDATE BUYER SET Name = @Name,Surname  = @Surname,Email =@Email,CellNumber =@CellNumber WHERE Email =@Email", con);
        //con.Open();

            cmd.Parameters.AddWithValue("@Name", txtNameUpdate.Text);
            cmd.Parameters.AddWithValue("@Surname", txtSurnameUpdate.Text);
            cmd.Parameters.AddWithValue("@Email", txtemailUpdate.Text);
            cmd.Parameters.AddWithValue("@CellNumber", txtCellUpdate.Text);
            cmd.BeginExecuteNonQuery();
        }

    catch (Exception e)
    {
        Console.WriteLine("Exception occured: " + e.StackTrace);
    }
   finally
   {
       // close connection if it is still open

       // editing from phone so just writting the comments here
    }
}

---

让我知道结果。