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();  
    }  
}  </pre>