Implementation code for converting DataSet, string, DataTable, and objects in C# into Json

public class ConvertJson
 {
  #region 私有方法
  /// <summary>
  /// 过滤特殊字符
  /// </summary>
  /// <param name="s">字符串</param>
  /// <returns>json字符串</returns>
  private static string String2Json(String s)
  {
   StringBuilder sb = new StringBuilder();
   for (int i = 0; i < s.Length; i++)
   {
    char c = s.ToCharArray()[i];
    switch (c)
    {
     case &#39;\"&#39;:
      sb.Append("\\\""); break;
     case &#39;\\&#39;:
      sb.Append("\\\\"); break;
     case &#39;/&#39;:
      sb.Append("\\/"); break;
     case &#39;\b&#39;:
      sb.Append("\\b"); break;
     case &#39;\f&#39;:
      sb.Append("\\f"); break;
     case &#39;\n&#39;:
      sb.Append("\\n"); break;
     case &#39;\r&#39;:
      sb.Append("\\r"); break;
     case &#39;\t&#39;:
      sb.Append("\\t"); break;
     default:
      sb.Append(c); break;
    }
   }
   return sb.ToString();
  }
  /// <summary>
  /// 格式化字符型、日期型、布尔型
  /// </summary>
  /// <param name="str"></param>
  /// <param name="type"></param>
  /// <returns></returns>
  private static string StringFormat(string str, Type type)
  {
   if (type == typeof(string))
   {
    str = String2Json(str);
    str = "\"" + str + "\"";
   }
   else if (type == typeof(DateTime))
   {
    str = "\"" + str + "\"";
   }
   else if (type == typeof(bool))
   {
    str = str.ToLower();
   }
   else if (type != typeof(string) && string.IsNullOrEmpty(str))
   {
    str = "\"" + str + "\"";
   }
   return str;
  }
  #endregion
 
  #region list转换成JSON
  /// <summary>
  /// list转换为Json
  /// </summary>
  /// <typeparam name="T"></typeparam>
  /// <param name="list"></param>
  /// <returns></returns>
  public static string ListToJson<T>(IList<T> list)
  {
   object obj = list[0];
   return ListToJson<T>(list, obj.GetType().Name);
  }
  /// <summary>
  /// list转换为json
  /// </summary>
  /// <typeparam name="T1"></typeparam>
  /// <param name="list"></param>
  /// <param name="p"></param>
  /// <returns></returns>
  private static string ListToJson<T>(IList<T> list, string JsonName)
  {
   StringBuilder Json = new StringBuilder();
   if (string.IsNullOrEmpty(JsonName))
    JsonName = list[0].GetType().Name;
   Json.Append("{\"" + JsonName + "\":[");
   if (list.Count > 0)
   {
    for (int i = 0; i < list.Count; i++)
    {
     T obj = Activator.CreateInstance<T>();
     PropertyInfo[] pi = obj.GetType().GetProperties();
     Json.Append("{");
     for (int j = 0; j < pi.Length; j++)
     {
      Type type = pi[j].GetValue(list[i], null).GetType();
      Json.Append("\"" + pi[j].Name.ToString() + "\":" + StringFormat(pi[j].GetValue(list[i], null).ToString(), type));
      if (j < pi.Length - 1)
      {
       Json.Append(",");
      }
     }
     Json.Append("}");
     if (i < list.Count - 1)
     {
      Json.Append(",");
     }
    }
   }
   Json.Append("]}");
   return Json.ToString();
  }
  #endregion
 
  #region 对象转换为Json
  /// <summary>
  /// 对象转换为json
  /// </summary>
  /// <param name="jsonObject">json对象</param>
  /// <returns>json字符串</returns>
  public static string ToJson(object jsonObject)
  {
   string jsonString = "{";
   PropertyInfo[] propertyInfo = jsonObject.GetType().GetProperties();
   for (int i = 0; i < propertyInfo.Length; i++)
   {
    object objectValue = propertyInfo[i].GetGetMethod().Invoke(jsonObject, null);
    string value = string.Empty;
    if (objectValue is DateTime || objectValue is Guid || objectValue is TimeSpan)
    {
     value = "&#39;" + objectValue.ToString() + "&#39;";
    }
    else if (objectValue is string)
    {
     value = "&#39;" + ToJson(objectValue.ToString()) + "&#39;";
    }
    else if (objectValue is IEnumerable)
    {
     value = ToJson((IEnumerable)objectValue);
    }
    else
    {
     value = ToJson(objectValue.ToString());
    }
    jsonString += "\"" + ToJson(propertyInfo[i].Name) + "\":" + value + ",";
   }
   jsonString.Remove(jsonString.Length - 1, jsonString.Length);
   return jsonString + "}";
  }
  #endregion
 
  #region 对象集合转换为json
  /// <summary>
  /// 对象集合转换为json
  /// </summary>
  /// <param name="array">对象集合</param>
  /// <returns>json字符串</returns>
  public static string ToJson(IEnumerable array)
  {
   string jsonString = "{";
   foreach (object item in array)
   {
    jsonString += ToJson(item) + ",";
   }
   jsonString.Remove(jsonString.Length - 1, jsonString.Length);
   return jsonString + "]";
  }
  #endregion
 
  #region 普通集合转换Json
  /// <summary> 
  /// 普通集合转换Json 
  /// </summary> 
  /// <param name="array">集合对象</param> 
  /// <returns>Json字符串</returns> 
  public static string ToArrayString(IEnumerable array)
  {
   string jsonString = "[";
   foreach (object item in array)
   {
    jsonString = ToJson(item.ToString()) + ",";
   }
   jsonString.Remove(jsonString.Length - 1, jsonString.Length);
   return jsonString + "]";
  }
  #endregion
 
  #region DataSet转换为Json
  /// <summary> 
  /// DataSet转换为Json 
  /// </summary> 
  /// <param name="dataSet">DataSet对象</param> 
  /// <returns>Json字符串</returns> 
  public static string ToJson(DataSet dataSet)
  {
   string jsonString = "{";
   foreach (DataTable table in dataSet.Tables)
   {
    jsonString += "\"" + table.TableName + "\":" + ToJson(table) + ",";
   }
   jsonString = jsonString.TrimEnd(&#39;,&#39;);
   return jsonString + "}";
  }
  #endregion
 
  #region Datatable转换为Json
  /// <summary>  
  /// Datatable转换为Json  
  /// </summary> 
  /// <param name="table">Datatable对象</param>  
  /// <returns>Json字符串</returns>  
  public static string ToJson(DataTable dt)
  {
   StringBuilder jsonString = new StringBuilder();
   jsonString.Append("[");
   DataRowCollection drc = dt.Rows;
   for (int i = 0; i < drc.Count; i++)
   {
    jsonString.Append("{");
    for (int j = 0; j < dt.Columns.Count; j++)
    {
     string strKey = dt.Columns[j].ColumnName;
     string strValue = drc[i][j].ToString();
     Type type = dt.Columns[j].DataType;
     jsonString.Append("\"" + strKey + "\":");
     strValue = StringFormat(strValue, type);
     if (j < dt.Columns.Count - 1)
     {
      jsonString.Append(strValue + ",");
     }
     else
     {
      jsonString.Append(strValue);
     }
    }
    jsonString.Append("},");
   }
   jsonString.Remove(jsonString.Length - 1, 1);
   jsonString.Append("]");
   return jsonString.ToString();
  }
  /// <summary> 
  /// DataTable转换为Json  
  /// </summary> 
  public static string ToJson(DataTable dt, string jsonName)
  {
   StringBuilder Json = new StringBuilder();
   if (string.IsNullOrEmpty(jsonName))
    jsonName = dt.TableName;
   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++)
     {
      Type type = dt.Rows[i][j].GetType();
      Json.Append("\"" + dt.Columns[j].ColumnName.ToString() + "\":" + StringFormat(dt.Rows[i][j].ToString(), type));
      if (j < dt.Columns.Count - 1)
      {
       Json.Append(",");
      }
     }
     Json.Append("}");
     if (i < dt.Rows.Count - 1)
     {
      Json.Append(",");
     }
    }
   }
   Json.Append("]}");
   return Json.ToString();
  }
  #endregion
 
  #region DataReader转换为Json
  /// <summary>  
  /// DataReader转换为Json  
  /// </summary>  
  /// <param name="dataReader">DataReader对象</param>  
  /// <returns>Json字符串</returns> 
  public static string ToJson(DbDataReader dataReader)
  {
   StringBuilder jsonString = new StringBuilder();
   jsonString.Append("[");
   while (dataReader.Read())
   {
    jsonString.Append("{");
    for (int i = 0; i < dataReader.FieldCount; i++)
    {
     Type type = dataReader.GetFieldType(i);
     string strKey = dataReader.GetName(i);
     string strValue = dataReader[i].ToString();
     jsonString.Append("\"" + strKey + "\":");
     strValue = StringFormat(strValue, type);
     if (i < dataReader.FieldCount - 1)
     {
      jsonString.Append(strValue + ",");
     }
     else
     {
      jsonString.Append(strValue);
     }
    }
    jsonString.Append("},");
   }
   dataReader.Close();
   jsonString.Remove(jsonString.Length - 1, 1);
   jsonString.Append("]");
   return jsonString.ToString();
  }
  #endregion
 }