Question

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

namespace Registration

{
    public partial class WebForm1 : System.Web.UI.Page
    {
        //checking if there is a user with the same username
        protected void Page_Load(object sender, EventArgs e)
        {
            if(IsPostBack)
            {
                SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString);
                conn.Open();
                string checkuser = "select count(*) from Table where UserName='" +FullName.Text +"'";
                SqlCommand cmd = new SqlCommand(checkuser, conn);
   //SqlException was unhandled of type"System.Data.SQlClient.SqlException" 
    //was not handled in user code
                int temp = Convert.ToInt32(cmd.ExecuteScalar().ToString());
                if (temp == 1)
                    Response.Write("User Already Exists");


                conn.Close();
            }



        }

        protected void Button1_Click(object sender, EventArgs e)
        {
         //Insert into my database table
            try
            {
                SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString);
                conn.Open();
                string insertuser = "insert into Table (Username,Email,Passwrod,Age,Degree) values (@username,@email,@password,@age,@degree)";
                SqlCommand cmd = new SqlCommand(insertuser, conn);
                cmd.Parameters.AddWithValue("@username" , FullName.Text);
                cmd.Parameters.AddWithValue("@email", Email.Text);
                cmd.Parameters.AddWithValue("@password", Password.Text);
                cmd.Parameters.AddWithValue("@age", Age.Text);
                cmd.Parameters.AddWithValue("@degree", Degree.Text);
                cmd.ExecuteNonQuery();
                Response.Write("Registration Successfull");

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

        }

        protected void GridView1_SelectedIndexChanged(object sender, EventArgs e)
        {

        }
    }
}

Answer 1

在pql中，

Table为reserved keyword，如果您的表名为表，则需要像[Table]一样正确包装，我也建议你把你的桌子命名为有意义的，现在它的名字含糊不清。

你还必须使用try catch块来防止你的应用程序崩溃，并且不要使用连接数据库访问代码来调查你的每个方法，而不是创建一个帮助器类并在那里移动常用功能，只需将其调用到其他所有地方易于维护的可重用性。

每当我提交表单时，我都会遇到此运行时错误

1 个答案: