EasyUI笔记（六）数据表格

 public void ProcessRequest(HttpContext context)
        {
            context.Response.ContentType = "text/plain";

            int page = 1, rows = 10;

            //EasyUI自带的两个参数rows与page ,表示当前页与行数  
            if (context.Request.QueryString["rows"] != null)
            {
                rows = int.Parse(context.Request.QueryString["rows"].ToString().Trim());
            }
            if (context.Request.QueryString["page"] != null)
            {
                page = int.Parse(context.Request.QueryString["page"].ToString().Trim());
            }

            //查询分页 stratIndex endIndex  
            int stratIndex, endIndex;
            stratIndex = (page - 1) * rows + 1;
            endIndex = page * rows;

            //查询排序 key order  
            string key = "", order = "desc";  
            if (context.Request.QueryString["key"] != null)  
            {  
                key = context.Request.QueryString["key"].ToString().Trim();  
            }  
            if (context.Request.QueryString["order"] != null)  
            {  
                order = context.Request.QueryString["order"].ToString().Trim();  
            }

            //设置模糊查询
            StringBuilder sqlWhere = new StringBuilder();
            if (key != "") {
                sqlWhere.AppendFormat("upper(ProductID) like '%{0}%' or "+
                                                            "upper(Name) like '%{0}%' or "+
                                                            "upper(Description) like '%{0}%' or " +
                                                            "upper(Category) like '%{0}%' or " +
                                                            "upper(Price) like '%{0}%'",key);
            }

            //查询数据库  
            DAL.SqlHelper sqlhelper = new DAL.SqlHelper();
            //获取查询数据的行数  
            int count = sqlhelper.EUGetRecordCount(sqlWhere.ToString());
            //封装数据到dataset  
            DataSet ds = sqlhelper.GetListByPagebykey(sqlWhere.ToString(), order, stratIndex, endIndex);
            //将dataset转化为Json格式  
            string strToJon = DAL.ToJson.DatasetJson(ds, count);
            context.Response.Write(strToJon);
            context.Response.End();  
        }

三、DAL数据访问层

接下来就是数据访问层SqlHelper的代码

public int EUGetRecordCount(string key)
        {
            StringBuilder strSql = new StringBuilder();
            strSql.Append("select count(1) FROM Products ");
            if (key.Trim() != "")
            {
                strSql.Append("where " + key);
            }
            object obj = DBHelper.GetSingle(strSql.ToString());
            if (obj == null)
            {
                return 0;
            }
            else
            {
                return Convert.ToInt32(obj);
            }
        }
public DataSet GetListByPagebykey(string Key, string order, int startIndex, int endIndex)
        {
            StringBuilder strSql = new StringBuilder();
            strSql.Append("SELECT * FROM ( ");
            strSql.Append(" SELECT ROW_NUMBER() OVER (");
            if (!string.IsNullOrEmpty(Key.Trim()))
            {
                strSql.Append("order by T." + Key+" " + order);
            }
            else
            {
                strSql.Append("order by T.ProductID asc");
            }
            strSql.Append(")AS Row, T.*  from  Products T ");
            if (!string.IsNullOrEmpty(Key.Trim()))
            {
                strSql.Append(" WHERE " + Key);
            }
            strSql.Append(" ) TT");
            strSql.AppendFormat(" WHERE TT.Row between {0} and {1}", startIndex, endIndex);
            return DBHelper.Query(strSql.ToString());
        }  

四、辅助方法

还需要dataset转json的代码，其实这个可以从网上找到

public class ToJson
    {
        /// <summary>
        /// DataSet转换成Json格式  
        /// </summary>  
        /// <param name="ds">DataSet</param> 
        /// <returns></returns>  
        public static string DatasetJson(DataSet ds, int total = -1)
        {
            StringBuilder json = new StringBuilder();

            foreach (DataTable dt in ds.Tables)
            {
                json.Append("{\"total\":");
                if (total == -1)
                {
                    json.Append(dt.Rows.Count);
                }
                else
                {
                    json.Append(total);
                }
                json.Append(",\"rows\":");
                json.Append(DataTableJson(dt));
                json.Append("]}");
            } return json.ToString();
        }
        private static string DataTableJson(DataTable dt)
        {
            StringBuilder jsonBuilder = new StringBuilder();
            jsonBuilder.Append("[");
            for (int i = 0; i < dt.Rows.Count; i++)
            {
                jsonBuilder.Append("{");
                for (int j = 0; j < dt.Columns.Count; j++)
                {
                    jsonBuilder.Append("\"");
                    jsonBuilder.Append(dt.Columns[j].ColumnName);
                    jsonBuilder.Append("\":\"");
                    jsonBuilder.Append(dt.Rows[i][j].ToString());
                    jsonBuilder.Append("\",");
                }
                jsonBuilder.Remove(jsonBuilder.Length - 1, 1);
                jsonBuilder.Append("},");
            }
            jsonBuilder.Remove(jsonBuilder.Length - 1, 1);
            return jsonBuilder.ToString();
        }
    }

到这就大致实现了网格加载的功能，还剩四个增删改查的按钮功能，这里只列出增加数据的数据访问层代码，其中应用了SqlParameter参数化SQL，可以防止SQL注入

 public int Add(Products model)
        {
            StringBuilder strSql = new StringBuilder();
            strSql.Append("insert into Products(");
            strSql.Append("Name,Description,Category,Price)");
            strSql.Append(" values (");
            strSql.Append("@Name,@Description,@Category,@Price)");
            strSql.Append(";select @@IDENTITY");
            SqlParameter[] parameters = {  
                new SqlParameter("@Name", SqlDbType.NVarChar,255),  
                new SqlParameter("@Description", SqlDbType.NVarChar,255),  
                new SqlParameter("@Category", SqlDbType.NVarChar,255),  
                new SqlParameter("@Price ", SqlDbType.Decimal,255),  
        };
            //parameters[0].Value = model.ProductID;
            parameters[0].Value = model.Name;
            parameters[1].Value = model.Description;
            parameters[2].Value = model.Category;
            parameters[3].Value = model.Price;

            object obj = DBHelper.GetSingle(strSql.ToString(), parameters);
            if (obj == null)
            {
                return 0;
            }
            else
            {
                return Convert.ToInt32(obj);
            }
        }