sql语句如何转换并传给成datatable

Question

DataTable users = this.CheckUser(tbUserName.Text, tbUserPwd.Text);public DataTable CheckUser(string name,string password)
        {            StringBuilder sql = new StringBuilder("SELECT * FROM USERS WHERE UID='")
                .Append(name).Append("'")
                .Append(" AND UPWD='").Append(password).Append("'");
            return sql.ToString();
     
        } 这个 DataTable users 能直接接收这个sql.ToString么？要怎么转换啊？还有如果如下写一个方法，该怎么写？就是用 return db.QuickSelect(sql.ToString());这个返回的话public abstract DataTable QuickSelect(string sql);

Answer 1

sql -> DataTable 是ADO.NET的知识，建议lz装个msdn
还差几步：
1) 创建Connection
2) 创建DataAdapter 参数:Connection, Sql文
3) 填充DataTable：
    DataTable data = new DataTable();
    DataAdapter.Fill(data)
    return data;

Answer 2

直接下个微软SQLHelper 类....调用那些方法就行了..

Answer 3

string sql="SELECT * FROM USERS WHERE UID='"+name+"' AND UPWD='"+password+"'" ;
参数化操作
string.format("SELECT * FROM USERS WHERE UID='{0}' and UPWD='{1}'",name,password)

Answer 4

private static void PrepareCommand(SqlCommand cmd, SqlConnection conn,
            string cmdText, SqlParameter[] p)
        {
            if (conn.State != ConnectionState.Open)
            {
                conn.Open();
            }            cmd.Parameters.Clear();
            cmd.Connection = conn;
            cmd.CommandText = cmdText;            cmd.CommandType = CommandType.Text;
            cmd.CommandTimeout = 30;            if (p != null)
            {
                foreach (SqlParameter parm in p)
                {
                    cmd.Parameters.Add(parm);
                }
            }
        }        #region 执行一条SQL语句，返回一个DataTable
        public DataTable GetDataTable(string sqlstr, params SqlParameter[] p)
        {
            using (conn = new SqlConnection (ConnectionString))
            {
                dt = new DataTable();
                try
                {
                    cmd = new SqlCommand();
                    PrepareCommand(cmd, conn, sqlstr, p);
                    sda = new SqlDataAdapter();
                    sda.SelectCommand = cmd;                    sda.Fill(dt);
                    return dt;
                }
                catch (Exception ex)
                {
                    ErrLog(string.Format("错误SQL语句：{0}；错误代码：{1}", sqlstr, ex.Message));
                    return dt;
                }
            }
        }
        #endregion