Question

这是我的代码，但它给了我错误，我将在下面写下

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

public partial class Info : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (IsPostBack)
        {
            SqlConnection Connection = new SqlConnection(ConfigurationManager.ConnectionStrings["SqlDataSource1"].ConnectionString);
            Connection.Open();
            string checkuser = "select count(*) from products where UserName='"+txtName.Text+"'";
           // SqlCommand Command = new SqlCommand(checkuser,Connection);

            int temp = Convert.ToInt32(Command.ExecuteScalar().ToString());

            if (temp == 1)
            {
                Response.Write("User Eneter invalid value ");
            }

            Connection.Close(); 
        }
    }

    protected void btnLast_Click(object sender, EventArgs e)
    {
        try
        {
            if (IsPostBack)
            {
               SqlConnection Connection = new SqlConnection(ConfigurationManager.ConnectionStrings["SqlDataSource1"].ConnectionString);
                Connection.Open();
                string insert = "insert into products (ID,FirstName,LastName) values (@User,@F,@L)";
                SqlCommand Command = new SqlCommand(insert, Connection);
                Command.Parameters.AddWithValue("@User", txtID);
                Command.Parameters.AddWithValue("@F", txtName);
                Command.Parameters.AddWithValue("@L", txtLast);

                Command.ExecuteNonQuery();

                Response.Redirect("Info.aspx");
                Response.Write("Connection Sucssesfull");

                Connection.Close();
            }
        }
        catch (Exception ex)
        {
            Response.Write("Error" + ex.ToString());
        }
    }
}

我收到错误：

  应用程序中的服务器错误。

编译错误

描述：编译服务此请求所需的资源时发生错误。请查看以下特定错误详细信息并相应地修改源代码。

编译器错误消息：CS0103：当前上下文中不存在名称“Command”

来源错误：
  第23行：int temp = Convert.ToInt32（Command.ExecuteScalar（）。ToString（））;

Answer 1

您必须将您的命令对象全局声明为：

 SqlCommand Command=null;

或

删除针对以下网址的评论：

SqlCommand Command = new SqlCommand(checkuser,Connection);

这将解决您的问题。

整个代码将是：

public partial class Info : System.Web.UI.Page { SqlCommand Command=null; protected void Page_Load(object sender, EventArgs e) { if (IsPostBack) { SqlConnection Connection = new SqlConnection(ConfigurationManager.ConnectionStrings["SqlDataSource1"].ConnectionString); Connection.Open(); string checkuser = "select count(*) from products where UserName='"+txtName.Text+"'"; //If you dont want to declare globally , remove below comment // SqlCommand Command = new SqlCommand(checkuser,Connection); int temp = Convert.ToInt32(Command.ExecuteScalar().ToString()); if (temp == 1) { Response.Write("User Eneter invalid value "); } Connection.Close(); } } protected void btnLast_Click(object sender, EventArgs e) { try { if (IsPostBack) { SqlConnection Connection = new SqlConnection(ConfigurationManager.ConnectionStrings["SqlDataSource1"].ConnectionString); Connection.Open(); string insert = "insert into products (ID,FirstName,LastName) values (@User,@F,@L)"; Command = new SqlCommand(insert, Connection); Command.Parameters.AddWithValue("@User", txtID); Command.Parameters.AddWithValue("@F", txtName); Command.Parameters.AddWithValue("@L", txtLast); Command.ExecuteNonQuery(); Response.Redirect("Info.aspx"); Response.Write("Connection Sucssesfull"); Connection.Close(); } } catch (Exception ex) { Response.Write("Error" + ex.ToString()); } } }

请帮助将数据插入数据库

1 个答案: