堆栈(Stack)就是栈
select OrderSn from ORDER_Tracking group by OrderSn having count(1)>=2
HttpClient httpclient = new HttpClient();
var ret = httpclient.GetAsync("https://www.baidu.com/");
var Content = ret.Result.Content.ReadAsStringAsync().Result;
UTF-8编码的文字可以在各国各种支持UTF-8字符集的浏览器上显示
在一个链接数据库的时候，老是出现超时的错误：执行超时已过期。完成操作之前已超时或服务器未响应。
就是给这个链接加上一个TimeOut的属性
public static DataSet ExeQuery(string Cmd)
Database db = DatabaseFactory.CreateDatabase(connstring_TMS);
DbConnection conn = db.CreateConnection();
DbCommand comm = conn.CreateCommand();
comm.CommandTimeout = 5000;//500秒，单位是秒
conn.Open();
comm.CommandText = Cmd;
DbDataReader read = comm.ExecuteReader();
return ConvertDataReaderToDataSet(read);
finally
conn.Close();
conn = null;
1 public static DataSet ConvertDataReaderToDataSet(DbDataReader reader)
3 DataSet dataSet = new DataSet();
4 do
6 // Create new data table
7 DataTable schemaTable = reader.GetSchemaTable();
8 DataTable dataTable = new DataTable();
9 if (schemaTable != null)
10 {
11 // A query returning records was executed
12 for (int i = 0; i < schemaTable.Rows.Count; i++)
13 {
14 DataRow dataRow = schemaTable.Rows[i];
15 // Create a column name that is unique in the data table
16 string columnName = (string)dataRow["ColumnName"]; //+ " // Add the column definition to the data table
17 DataColumn column = new DataColumn(columnName, (Type)dataRow["DataType"]);
18 dataTable.Columns.Add(column);
19 }
20 dataSet.Tables.Add(dataTable);
21 // Fill the data table we just created
22 while (reader.Read())
23 {
24 DataRow dataRow = dataTable.NewRow();
25 for (int i = 0; i < reader.FieldCount; i++)
26 {
27 dataRow[i] = reader.GetValue(i);
28 }
29 dataTable.Rows.Add(dataRow);
30 }
31 }
32 else
33 {
34 // No records were returned
35 DataColumn column = new DataColumn("RowsAffected");
36 dataTable.Columns.Add(column);
37 dataSet.Tables.Add(dataTable);
38 DataRow dataRow = dataTable.NewRow();
39 dataRow[0] = reader.RecordsAffected;
40 dataTable.Rows.Add(dataRow);
41 }
42 }
43 while (reader.NextResult());
44 return dataSet;
