DataSet、DataTable、Json、List 等各种数据的相互转化

1.根据Dataset生成json格式的字符串，不管Dataset里面有多少个表都可以一一生成对应的json字符串，并一次性返回

private string dsToJson(DataSet ds)
{
System.Text.StringBuilder str = new System.Text.StringBuilder("[");
for (int o = ; o < ds.Tables.Count; o++)
{
str.Append("{");
str.Append(string.Format("\"{0}\":[", ds.Tables[o].TableName));

for (int i = ; i < ds.Tables[].Rows.Count; i++)
{
str.Append("{");
for (int j = ; j < ds.Tables[].Columns.Count; j++)
{
str.Append(string.Format("\"{0}\":\"{1}\",", ds.Tables[].Columns[j].ColumnName, ds.Tables[].Rows[i][j].ToString()));
}
str.Remove(str.Length - , );
str.Append("},");
}
str.Remove(str.Length - , );
str.Append("]},");
}
str.Remove(str.Length - , );
str.Append("]");
return str.ToString();
}

2.数据库中的内容转换成json数据

  [WebMethod]
        [ScriptMethod(ResponseFormat = ResponseFormat.Json)]
        private string dsToJson()
        {
            System.Text.StringBuilder str = new System.Text.StringBuilder("[");
            for (int o = ; o < ds.Tables.Count; o++)
            {
                str.Append("{");
                str.Append(string.Format("\"{0}\":[", ds.Tables[o].TableName));

                for (int i = ; i < ds.Tables[].Rows.Count; i++)
                {
                    str.Append("{");
                    for (int j = ; j < ds.Tables[].Columns.Count; j++)
                    {
                        str.Append(string.Format("\"{0}\":\"{1}\",", ds.Tables[].Columns[j].ColumnName, ds.Tables[].Rows[i][j].ToString()));
                    }
                    str.Remove(str.Length - , );
                    str.Append("},");
                }
                str.Remove(str.Length - , );
                str.Append("]},");
            }
            str.Remove(str.Length - , );
            str.Append("]");

            return str.ToString();
        }

3.C# - list<>数据填充到Dataset里

publicstatic DataSet ConvertToDataSet<T>(IList<T> list)
    {
        if (list ==null|| list.Count <=)
        {
            returnnull;
        }
        DataSet ds =new DataSet();
        DataTable dt =new DataTable(typeof(T).Name);
        DataColumn column;
        DataRow row;

        System.Reflection.PropertyInfo[] myPropertyInfo =typeof(T).GetProperties(System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance);
        foreach (T t in list)
        {
            if (t ==null)
            {
                continue;
            }
            row = dt.NewRow();
            for (int i =, j = myPropertyInfo.Length; i < j; i++)
            {
                System.Reflection.PropertyInfo pi = myPropertyInfo[i];
                string name = pi.Name;
                if (dt.Columns[name] ==null)
                {
                    column =new DataColumn(name, pi.PropertyType);
                    dt.Columns.Add(column);
                }
                row[name] = pi.GetValue(t, null);
            }
            dt.Rows.Add(row);
        }
        ds.Tables.Add(dt);
        return ds;
    }
}

4.DataSet 和 Datable 的相互转化

DataSet ds = DbHelperSQL.Query("select * from text_table where a='3'");
string strtext = ds.Tables[].Rows[]["bz"].ToString();

5.List转化成数组

List<string> a = new List<string>();
        public string[] getString(TreeNodeCollection item)
        {
            NumMethod(item);
            return a.ToArray();
        }

6.将字符转转化成数组并以逗号分割，即，去掉逗号

string strszcdid = "1111,111111,111112,111211,111311,";

string[] a = strszcdid.Split(',');

7.截取字符转从字符串指定位置截取到固定的长度

id = id.Substring(, id.Length - );