正在做一个.net的管理系统，刚开始学，新手问题

Question

我用设计页面，加上div等等的设计了一个很简单的登陆界面，现在想将登陆信息和数据库中的信息比较，好确定登陆权限，我在登陆按钮的事件中写了如下代码想用数据库中的信息做比较，但是不能引用login.aspx中的名称和信息，怎么办，我刚开始学不太懂，希望大神们指点一下，能加一下QQ更感谢了，我们下个月要交一个系统作业，我想做的好一点~我的QQ是1484848401. protected void LoginButton_Click(object sender, EventArgs e)
        {
            SqlConnection conn = new SqlConnection(@"Data Source=FACE;Initial Catalog=仓库管理系统;Integrated Security=True");
            {
                conn.Open();
                using (SqlCommand cmd = conn.CreateCommand())
                {
                    
                    cmd.CommandText = "select * from userlog where username='" + UserName + "'";                }            }
        }

Answer 1

你的login.aspx页面不是有输入用户名信息的文本框嘛，你在登录按钮中取得文本框中的值，然后到数据库中查询比较一下，不就行了。
protected void LoginButton_Click(object sender, EventArgs e)
        {
            using(SqlConnection conn = new SqlConnection(@"Data Source=FACE;Initial Catalog=仓库管理系统;Integrated Security=True"))
            {
                conn.Open();
                using (SqlCommand cmd = conn.CreateCommand())
                {
                    
                    cmd.CommandText = "select * from userlog where username='" + This.TextBox1.Text.Trim() + "'";
                    using(SqlDataReader reader = cmd.ExecuteNonQuery())
                    {
                        if(reader.Read())
                        {
                          Response.Redirect("index.aspx"); //有配置的记录，进行跳转
                        }
                        else
                        {
                            Response.Redirect("login.aspx"); //没有配置的记录，跳转重新登录                        }
                    }                }            }
        }
 
 

Answer 2

protected void LoginButton_Click(object sender, EventArgs e)
{
    using(SqlConnection conn = new SqlConnection(@"Data Source=FACE;Initial Catalog=仓库管理系统;Integrated Security=True"))
    {
       conn.Open();
       using (SqlCommand cmd = conn.CreateCommand())
       {
            cmd.CommandText = "select * from userlog where username='" + This.TextBox1.Text.Trim() + "'";
            using(SqlDataReader reader = cmd.ExecuteNonQuery())
            {
                if(reader.Read())
                {
                    Response.Redirect("index.aspx"); //有配置的记录，进行跳转
                   }
                 else
                 {
                    Response.Redirect("login.aspx"); //没有配置的记录，跳转重新登录                  }
             }          }      }
   }
 

Answer 3

protected void LoginButton_Click(object sender, EventArgs e)
{
    using(SqlConnection conn = new SqlConnection(@"Data Source=FACE;Initial Catalog=仓库管理系统;Integrated Security=True"))
    {
       conn.Open();
       using (SqlCommand cmd = conn.CreateCommand())
       {
            cmd.CommandText = "select * from userlog where username='" + This.TextBox1.Text.Trim() + "'";
            using(SqlDataReader reader = cmd.ExecuteNonQuery())
            {
                if(reader.Read())
                {
                    Response.Redirect("index.aspx"); //有配置的记录，进行跳转
                   }
                 else
                 {
                    Response.Redirect("login.aspx"); //没有配置的记录，跳转重新登录                  
                    }
             }          }      }
   }

Answer 4

对照着教程自己练习吧拖用户名/密码/按钮这几个控件到设计页在后代码中通过事件可直接访问控件值
protected void userLogin_Click(object sender, EventArgs e)
        {
            int result = -1;
            string username = TextUsername.Text;
            string pass = TextPass.Text;
            SqlParameter[] param = new SqlParameter[]{
            new SqlParameter("@username ", username ),
            new SqlParameter("@pass ", pass )
           };
            string sql = "select count(*) from userlog where username=@username  and password=@pass ";
           result = (int)ExecuteScalar(CommandType.Text, sql, param);
            
            if(result>0)
                 //验证通过
            else
                //失败        }

Answer 5

刚才楼上给的也不行  this 也是没有定义的 是怎么回事

Answer 6

哪里 this没有定义，引用：SQLHelper类 了吗

Answer 7

我手里有个sqlhelper的类 该怎么用
[code=C/C++]using System.Data;
using System.Data.SqlClient;
using System.Configuration;
using System.Data.Common;
using System.Collections.Generic;
    /// <summary>
    /// 数据访问抽象基础类
    /// Copyright (C) 2004-2008 By LiTianPing 
    /// </summary>
    public abstract class DbHelperSQL
    {
        //数据库连接字符串(web.config来配置)，可以动态更改connectionString支持多数据库.
        public static string connectionString = ConfigurationManager.AppSettings["DbHelperConnectionString"].ToString();     
        public DbHelperSQL()
        {            
        }        #region 公用方法
        /// <summary>
        /// 判断是否存在某表的某个字段
        /// </summary>
        /// <param name="tableName">表名称</param>
        /// <param name="columnName">列名称</param>
        /// <returns>是否存在</returns>
        public static bool ColumnExists(string tableName, string columnName)
        {
            string sql = "select count(1) from syscolumns where [id]=object_id('" + tableName + "') and [name]='" + columnName + "'";
            object res = GetSingle(sql);
            if (res == null)
            {
                return false;
            }
            return Convert.ToInt32(res) > 0;
        }
        public static int GetMaxID(string FieldName, string TableName)
        {
            string strsql = "select max(" + FieldName + ")+1 from " + TableName;
            object obj = GetSingle(strsql);
            if (obj == null)
            {
                return 1;
            }
            else
            {
                return int.Parse(obj.ToString());
            }
        }
        public static bool Exists(string strSql)
        {
            object obj = GetSingle(strSql);
            int cmdresult;
            if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
            {
                cmdresult = 0;
            }
            else
            {
                cmdresult = int.Parse(obj.ToString());
            }
            if (cmdresult == 0)
            {
                return false;
            }
            else
            {
                return true;
            }
        }
        /// <summary>
        /// 表是否存在
        /// </summary>
        /// <param name="TableName"></param>
        /// <returns></returns>
        public static bool TabExists(string TableName)
        {
            string strsql = "select count(*) from sysobjects where id = object_id(N'[" + TableName + "]') and OBJECTPROPERTY(id, N'IsUserTable') = 1";
            //string strsql = "SELECT count(*) FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[" + TableName + "]') AND type in (N'U')";
            object obj = GetSingle(strsql);
            int cmdresult;
            if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
            {
                cmdresult = 0;
            }
            else
            {
                cmdresult = int.Parse(obj.ToString());
            }
            if (cmdresult == 0)
            {
                return false;
            }
            else
            {
                return true;
            }
        }
        public static bool Exists(string strSql, params SqlParameter[] cmdParms)
        {
            object obj = GetSingle(strSql, cmdParms);
            int cmdresult;
            if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
            {
                cmdresult = 0;
            }
            else
            {
                cmdresult = int.Parse(obj.ToString());
            }
            if (cmdresult == 0)
            {
                return false;
            }
            else
            {
                return true;
            }
        }
        #endregion        #region  执行简单SQL语句        /// <summary>
        /// 执行SQL语句，返回影响的记录数
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <returns>影响的记录数</returns>
        public static int ExecuteSql(string SQLString)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                using (SqlCommand cmd = new SqlCommand(SQLString, connection))
                {
                    try
                    {
                        connection.Open();
                        int rows = cmd.ExecuteNonQuery();
                        return rows;
                    }
                    catch (System.Data.SqlClient.SqlException e)
                    {
                        connection.Close();
                        throw e;
                    }
                }
            }
        }        public static int ExecuteSqlByTime(string SQLString, int Times)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                using (SqlCommand cmd = new SqlCommand(SQLString, connection))
                {
                    try
                    {
                        connection.Open();
                        cmd.CommandTimeout = Times;
                        int rows = cmd.ExecuteNonQuery();
                        return rows;
                    }
                    catch (System.Data.SqlClient.SqlException e)
                    {
                        connection.Close();
                        throw e;
                    }
                }
            }
        }
      
              
        /// <summary>
        /// 执行多条SQL语句，实现数据库事务。
        /// </summary>
        /// <param name="SQLStringList">多条SQL语句</param>
        public static int ExecuteSqlTran(List<String> SQLStringList)
        {
            using (SqlConnection conn = new SqlConnection(connectionString))
            {
                conn.Open();
                SqlCommand cmd = new SqlCommand();
                cmd.Connection = conn;
                SqlTransaction tx = conn.BeginTransaction();
                cmd.Transaction = tx;
                try
                {
                    int count = 0;
                    for (int n = 0; n < SQLStringList.Count; n++)
                    {
                        string strsql = SQLStringList[n];
                        if (strsql.Trim().Length > 1)
                        {
                            cmd.CommandText = strsql;
                            count += cmd.ExecuteNonQuery();
                        }
                    }
                    tx.Commit();
                    return count;
                }
                catch
                {
                    tx.Rollback();
                    return 0;
                }
            }
        }
        /// <summary>
        /// 执行带一个存储过程参数的的SQL语句。
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <param name="content">参数内容,比如一个字段是格式复杂的文章，有特殊符号，可以通过这个方式添加</param>
        /// <returns>影响的记录数</returns>
        public static int ExecuteSql(string SQLString, string content)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                SqlCommand cmd = new SqlCommand(SQLString, connection);
                System.Data.SqlClient.SqlParameter myParameter = new System.Data.SqlClient.SqlParameter("@content", SqlDbType.NText);
                myParameter.Value = content;
                cmd.Parameters.Add(myParameter);
                try
                {
                    connection.Open();
                    int rows = cmd.ExecuteNonQuery();
                    return rows;
                }
                catch (System.Data.SqlClient.SqlException e)
                {
                    throw e;
                }
                finally
                {
                    cmd.Dispose();
                    connection.Close();
                }
            }
        }
        /// <summary>
        /// 执行带一个存储过程参数的的SQL语句。
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <param name="content">参数内容,比如一个字段是格式复杂的文章，有特殊符号，可以通过这个方式添加</param>
        /// <returns>影响的记录数</returns>
        public static object Execute[code]

Answer 8

哥们 不行啊 编译说 this没有定义。。不能引用啊

Answer 9

你的是WinForm的？我的是举个例子，是你WebForm中那个输入用户名的文本框的ID叫TextBox1请输入用户名:<asp:TextBox ID="tbUserName" runat="server"></asp:TextBox>在点击登录的按钮事件中获取文本框的内容
string userName = this.tbUserName.Text.Trim();