Question

我正在使用我的用户的编辑页面来查看和更改文本框中的数据，他们可以从主页上的gridview访问这些数据。我在自动增量列ProductId上使用数据键，行数据显示完美。不幸的是，当我触发单击按钮事件以使用这些文本框中所做的更改来更新行时，它们不会注册。我已经包含了下面的代码，但作为一个说明，这是一个培训项目，我明确禁止首先学习基础知识。我意识到这是一个安全问题，但是现在，没有参数。为了澄清和重述我的问题，当我单击提交按钮时，行数据不受输入到文本框中的更改的影响，而是恢复为原始值。我知道这可能与查询字符串有关，但我不知道是什么。想法？

 using System;
using System.Collections.Generic;
using System.Linq;
using System.Data;
using System.Data.Sql;
using System.Data.SqlClient;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class ViewEdit : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        string x = Request.QueryString["ProductId"];
        string connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["MyConnectionString"].ConnectionString;
        string editQuery = "SELECT CustId, CustName, SicNaic, CustCity, CustAdd, CustState, CustZip, BroName, BroId, BroAdd, BroCity, BroState, BroZip, EntityType, Coverage, CurrentCoverage, PrimEx, Retention, EffectiveDate, Commission, Premium, Comments, ProductId FROM ProductInstance WHERE ProductId =" + x;



    using (SqlConnection editConn = new SqlConnection(connectionString))
    {
        editConn.Open();

        using (SqlCommand command = new SqlCommand(editQuery, editConn))
        {

            SqlDataReader dr = command.ExecuteReader();
            dr.Read();
            TextBox1.Text = dr.GetInt32(0).ToString();
            TextBox2.Text = dr.GetString(1);
            TextBox3.Text = dr.GetString(2);
            TextBox4.Text = dr.GetString(3);
            TextBox5.Text = dr.GetString(4);
            TextBox6.Text = dr.GetString(5);
            TextBox7.Text = dr.GetInt32(6).ToString();
            TextBox8.Text = dr.GetString(7);
            TextBox9.Text = dr.GetInt32(8).ToString();
            TextBox10.Text = dr.GetString(9);
            TextBox11.Text = dr.GetString(10);
            TextBox12.Text = dr.GetString(11);
            TextBox13.Text = dr.GetInt32(12).ToString();
            TextBox14.Text = dr.GetString(13);
            TextBox15.Text = dr.GetInt32(14).ToString();
            TextBox16.Text = dr.GetInt32(15).ToString();
            TextBox17.Text = dr.GetInt32(16).ToString();
            TextBox18.Text = dr.GetInt32(17).ToString();
            TextBox19.Text = dr.GetDateTime(18).ToString();
            TextBox20.Text = dr.GetInt32(19).ToString();
            TextBox21.Text = dr.GetInt32(20).ToString();
            TextBox22.Text = dr.GetString(21);



        }
        editConn.Close();
    }   
}

protected void Button1_Click(object sender, EventArgs e)
{
    string x = Request.QueryString["ProductId"];
    string connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["MyConnectionString"].ConnectionString;
    using (SqlConnection updateConn = new SqlConnection(connectionString))
    {
        updateConn.Open();
        {
            string updateQuery = "UPDATE ProductInstance SET CustId = '" + TextBox1.Text + "', CustName = '" + TextBox2.Text + "', SicNaic = '" + TextBox3.Text + "', CustCity =  '" + TextBox4.Text + "', CustAdd = '" + TextBox5.Text + "', CustState =  '" + TextBox6.Text + "', CustZip =  '" + TextBox7.Text + "', BroName = '" + TextBox8.Text + "', BroId =  '" + TextBox9.Text + "', BroAdd =  '" + TextBox10.Text + "', BroCity = '" + TextBox11.Text + "', BroState =  '" + TextBox12.Text + "', BroZip =  '" + TextBox13.Text + "', EntityType =  '" + TextBox14.Text + "', Coverage =  '" + TextBox15.Text + "', CurrentCoverage =  '" + TextBox16.Text + "', PrimEx = '" + TextBox17.Text + "', Retention = '" + TextBox18.Text + "', EffectiveDate =  '" + TextBox19.Text + "', Commission = '" + TextBox20.Text + "', Premium =  '" + TextBox21.Text + "', Comments = '" + TextBox22.Text + "' WHERE ProductId =" + x;



            using (SqlCommand command = new SqlCommand(updateQuery, updateConn))
            {
                command.ExecuteNonQuery();
            }
        }
    }
}

}

Answer 1

Brazos，

这是因为当进行更改并将其发回页面时，Page_Load再次执行，然后才能将从表单收集的值保存回数据库。而是使用数据库中的值加载文本框，并覆盖任何更改。稍后，当Button1_Click事件发生并且您执行将数据保存到数据库时，您使用文本框中的值更新行，这些值现在反映了数据库中的内容，而不是以表格提交。

在此处查看ASP.NET页面生命周期中的事件顺序： http://msdn.microsoft.com/en-us/library/ms178472.aspx

解决这个问题的一个简单方法是，只运行加载和更新文本框的查询（在Page_Load中），如果它不在回发中：

public partial class ViewEdit : System.Web.UI.Page {
    protected void Page_Load(object sender, EventArgs e)
    {

        if (!Page.IsPostBack)
        {
            string x = Request.QueryString["ProductId"];
            string connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["MyConnectionString"].ConnectionString;
            string editQuery = "SELECT CustId, CustName, SicNaic, CustCity, CustAdd, CustState, CustZip, BroName, BroId, BroAdd, BroCity, BroState, BroZip, EntityType, Coverage, CurrentCoverage, PrimEx, Retention, EffectiveDate, Commission, Premium, Comments, ProductId FROM ProductInstance WHERE ProductId =" + x;



        using (SqlConnection editConn = new SqlConnection(connectionString))
        {
            editConn.Open();

            using (SqlCommand command = new SqlCommand(editQuery, editConn))
            { [...]

但是，这也意味着在更改完成后，您将不再从数据库重新加载更改，因为之后的每个页面事件都将是回发（除非您执行重定向）。由于您正在学习ASP.NET，我建议您查看页面生命周期并探索不同的解决方案。祝你好运！

Answer 2

在Page_Load中检查回发

protected void Page_Load(object sender, EventArgs e)     
{         
    if (Page.IsPostBack == false)
    {
        string x = Request.QueryString["ProductId"];         
        string connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["MyConnectionString"].ConnectionString;         string editQuery = "SELECT CustId, CustName, SicNaic, CustCity, CustAdd, CustState, CustZip, BroName, BroId, BroAdd, BroCity, BroState, BroZip, EntityType, Coverage, CurrentCoverage, PrimEx, Retention, EffectiveDate, Commission, Premium, Comments, ProductId FROM ProductInstance WHERE ProductId =" + x;
    }
}

Answer 3

你应该在这样的页面上做的第一件事就是检查！IsPostBack然后执行标准过程来渲染代码中的页面：

protected void Page_Load(object sender, EventArgs e)
{         
    if (!IsPostBack)
    {
        // Add your normal code in here
    }
}

然后在您的点击事件中，在完成对数据库的插入后重新绑定数据

protected void Button1_Click(object sender, EventArgs e)
{
    // Do Insertion here
    lstView.DataSource = sqlVals;
    lstView.DataBind();
}

还可以阅读EF4或LinqToSql，因为它可以使SQL的数据调用更容易，更安全

更新没有用查询字符串执行？

3 个答案: