DataTable轉為JSON數據格式代碼

做項目要用到DataTable轉為JSON數據，在前台用ExtJs來操作。所以把這個方法放上來：

 1 public static string GetJSON(DataTable dt)
 2 {
 3     StringBuilder sb = new StringBuilder();
 4     sb.Append("{"totalCount":" + dt.Rows.Count + ","data":");
 5     sb.Append("[");
 6     try
 7     {
 8         if (dt.Rows.Count > 0)
 9         {
10             Hashtable ht = new Hashtable();
11             for (int i = 0; i < dt.Columns.Count; i++)
12             {
13                 ht.Add(i, dt.Columns[i].ColumnName);
14             }
15             for (int i = 0; i < dt.Rows.Count; i++)
16             {
17                 sb.Append("{");
18                 for (int j = 0; j < dt.Columns.Count; j++)
19                 {
20                     sb.Append(string.Format(""{0}":"{1}",",
21                         ht[j], dt.Rows[i][j].ToString()));
22                 }
23                 sb.Remove(sb.ToString().LastIndexOf(","), 1);
24                 sb.Append("},");
25             }
26