常用的C#类

    using System;  
    using System.Collections.Generic;  
    using System.Data;  
    using System.Linq;  
    using System.Text;  
    using System.Web;  
      
      
    /// <summary>  
    /// DataTableConvertJson 的摘要说明  
    /// </summary>  
    public class DataTableConvertJson  
    {  
        public DataTableConvertJson()  
        {  
            //  
            // TODO: 在此处添加构造函数逻辑  
            //  
        }  
     
     
        #region dataTable转换成Json格式  
        /// <summary>    
        /// dataTable转换成Json格式    
        /// </summary>    
        /// <param name="dt"></param>    
        /// <returns></returns>    
        public static string DataTable2Json(DataTable dt)  
        {  
            StringBuilder jsonBuilder = new StringBuilder();  
            //jsonBuilder.Append("{"");  
            //jsonBuilder.Append(dt.TableName);  
            //jsonBuilder.Append("[");  
            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);  
            jsonBuilder.Append("]");  
            //jsonBuilder.Append("}");  
            return jsonBuilder.ToString();  
        }  
     
     
        #endregion dataTable转换成Json格式  
        #region DataSet转换成Json格式  
        /// <summary>    
        /// DataSet转换成Json格式    
        /// </summary>    
        /// <param name="ds">DataSet</param>   
        /// <returns></returns>    
        public static string Dataset2Json(DataSet ds)  
        {  
            StringBuilder json = new StringBuilder();  
      
      
            foreach (DataTable dt in ds.Tables)  
            {  
                json.Append("{"");  
                json.Append(dt.TableName);  
                json.Append("":");  
                json.Append(DataTable2Json(dt));  
                json.Append("}");  
            } return json.ToString();  
        }  
        #endregion  
      
      
        /// <summary>  
        /// Msdn  
        /// </summary>  
        /// <param name="jsonName"></param>  
        /// <param name="dt"></param>  
        /// <returns></returns>  
        public static string DataTableToJson(string jsonName,DataTable dt)  
        {  
            StringBuilder Json = new StringBuilder();  
            Json.Append("{"" + jsonName + "":[");  
            if (dt.Rows.Count > 0)  
            {  
                for (int i = 0; i < dt.Rows.Count; i++)  
                {  
                    Json.Append("{");  
                    for (int j = 0; j < dt.Columns.Count; j++)  
                    {  
                        Json.Append(""" + dt.Columns[j].ColumnName.ToString() + "":"" + dt.Rows[i][j].ToString() + """);  
                        if (j < dt.Columns.Count - 1)  
                        {  
                            Json.Append(",");  
                        }  
                    }  
                    Json.Append("}");  
                    if (i < dt.Rows.Count - 1)  
                    {  
                        Json.Append(",");  
                    }  
                }  
            }  
            Json.Append("]}");  
            return Json.ToString();  
        }  
    }