异步的SQL数据库封装详解

namespace SQLWrapper 
{ 
 public class DAL : BLL 
 { 
  public DAL(string server, string db, string user, string pass) 
  { 
   base.Start(server, db, user, pass); 
  } 
 
  ~DAL() 
  { 
   base.Stop(eStopType.ForceStopAll); 
  } 
 
  /////////////////////////////////////////////////////////// 
  // TODO: Here you can add your code here... 
 } 
} 

public int MyStoreProcedure(int param1, string param2) 
{ 
  // 根据存储过程的返回类型创建用户数据 
  StoredProcedureCallbackResult userData = new StoredProcedureCallbackResult(eRequestType.Scalar); 
   
  // 在此定义传入存储过程的参数，如果没有参数可以省略 <span style="line-height:1.5;font-size:9pt;">userData.Parameters = new System.Data.SqlClient.SqlParameter[] { </span>     
 new System.Data.SqlClient.SqlParameter("@param1", param1), 
    new System.Data.SqlClient.SqlParameter("@param2", param2), 
  }; 
   
  // Execute procedure... 
  if (!ExecuteStoredProcedure("usp_MyStoreProcedure", userData)) 
    throw new Exception("Execution failed"); 
     
  // 等待执行完成... 
  // 等待时长为 <userdata.tswaitforresult> 
  // 执行未完成返回 <timeout> 
  if (WaitSqlCompletes(userData) != eWaitForSQLResult.Success) 
    throw new Exception("Execution failed"); 
     
  // Get the result... 
  return userData.ScalarValue; 
} 

public bool MySQLQuery(int param1, string param2) 
{ 
  // Create user data according to return type of store procedure in SQL(这个注释没有更新,说明《注释是魔鬼》有点道理) 
  ReaderQueryCallbackResult userData = new ReaderQueryCallbackResult(); 
   
  string sqlCommand = string.Format("SELECT TOP(1) * FROM tbl1 
   WHERE code = {0} AND name LIKE '%{1}%'", param1, param2); 
   
  // Execute procedure... 
  if (!ExecuteSQLStatement(sqlCommand, userData)) 
    return false; 
     
  // Wait until it finishes... 
  // Note, it will wait (userData.tsWaitForResult) 
  // for the command to be completed otherwise returns <timeout> 
  if (WaitSqlCompletes(userData) != eWaitForSQLResult.Success) 
    return false; 
     
  // Get the result... 
  if(userData.resultDataReader.HasRows && userData.resultDataReader.Read()) 
  { 
    // Do whatever you want.... 
    int field1 = GetIntValueOfDBField(userData.resultDataReader["Field1"], -1); 
    string field2 = GetStringValueOfDBField(userData.resultDataReader["Field2"], null); 
    Nullable<datetime> field3 = GetDateValueOfDBField(userData.resultDataReader["Field3"], null); 
    float field4 = GetFloatValueOfDBField(userData.resultDataReader["Field4"], 0); 
    long field5 = GetLongValueOfDBField(userData.resultDataReader["Field5"], -1); 
  } 
  userData.resultDataReader.Dispose(); 
   
  return true; 
} 

/// <summary> 
/// 你需要周期性地调用WaitSqlCompletes(userData, 10) 
/// 来查看结果是否可用! 
/// </summary> 
public StoredProcedureCallbackResult MyStoreProcedureASYNC(int param1, string param2) 
{ 
  // Create user data according to return type of store procedure in SQL 
  StoredProcedureCallbackResult userData = new StoredProcedureCallbackResult(eRequestType.Reader); 
   
  // If your store procedure accepts some parameters, define them here, 
  // or you can omit it incase there is no parameter definition 
  userData.Parameters = new System.Data.SqlClient.SqlParameter[] { 
    new System.Data.SqlClient.SqlParameter("@param1", param1), 
    new System.Data.SqlClient.SqlParameter("@param2", param2), 
  }; 
   
  // Execute procedure... 
  if (!ExecuteStoredProcedure("usp_MyStoreProcedure", userData)) 
    throw new Exception("Execution failed"); 
     
  return userData; 
} 

... 
DAL.StoredProcedureCallbackResult userData = myDal.MyStoreProcedureASYNC(10,"hello"); 
... 
// each time we wait 10 milliseconds to see the result... 
switch(myDal.WaitSqlCompletes(userData, 10)) 
{ 
case eWaitForSQLResult.Waiting: 
 goto WAIT_MORE; 
case eWaitForSQLResult.Success: 
 goto GET_THE_RESULT; 
default: 
 goto EXECUTION_FAILED; 
} 
... 

userData.tsWaitForResult = TimeSpan.FromSeconds(15);