?? sqlhelper.cs
字號:
AssignParameterValues(commandParameters, parameterValues);
//call the overload that takes an array of SqlParameters
return ExecuteDataset(connectionString, CommandType.StoredProcedure, spName, commandParameters);
}
//otherwise we can just call the SP without params
else
{
return ExecuteDataset(connectionString, CommandType.StoredProcedure, spName);
}
}
//*********************************************************************
//
// Execute a SqlCommand (that returns a resultset) against the specified SqlConnection
// using the provided parameters.
//
// e.g.:
// DataSet ds = ExecuteDataset(conn, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
//
// param name="connection" a valid SqlConnection
// param name="commandType" the CommandType (stored procedure, text, etc.)
// param name="commandText" the stored procedure name or T-SQL command
// param name="commandParameters" an array of SqlParamters used to execute the command
// returns a dataset containing the resultset generated by the command
//
//*********************************************************************
public static DataSet ExecuteDataset(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
{
//create a command and prepare it for execution
SqlCommand cmd = new SqlCommand();
PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters);
//create the DataAdapter & DataSet
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
//fill the DataSet using default values for DataTable names, etc.
da.Fill(ds);
// detach the SqlParameters from the command object, so they can be used again.
cmd.Parameters.Clear();
//return the dataset
return ds;
}
//*********************************************************************
//
// Execute a SqlCommand (that returns a 1x1 resultset) against the database specified in the connection string
// using the provided parameters.
//
// e.g.:
// int orderCount = (int)ExecuteScalar(connString, CommandType.StoredProcedure, "GetOrderCount", new SqlParameter("@prodid", 24));
//
// param name="connectionString" a valid connection string for a SqlConnection
// param name="commandType" the CommandType (stored procedure, text, etc.)
// param name="commandText" the stored procedure name or T-SQL command
// param name="commandParameters" an array of SqlParamters used to execute the command
// returns an object containing the value in the 1x1 resultset generated by the command
//
//*********************************************************************
public static object ExecuteScalar(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
{
//create & open a SqlConnection, and dispose of it after we are done.
using (SqlConnection cn = new SqlConnection(connectionString))
{
cn.Open();
//call the overload that takes a connection in place of the connection string
return ExecuteScalar(cn, commandType, commandText, commandParameters);
}
}
//*********************************************************************
//
// Execute a stored procedure via a SqlCommand (that returns a 1x1 resultset) against the database specified in
// the connection string using the provided parameter values. This method will query the database to discover the parameters for the
// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
//
// This method provides no access to output parameters or the stored procedure's return value parameter.
//
// e.g.:
// int orderCount = (int)ExecuteScalar(connString, "GetOrderCount", 24, 36);
//
// param name="connectionString" a valid connection string for a SqlConnection
// param name="spName" the name of the stored procedure
// param name="parameterValues" an array of objects to be assigned as the input values of the stored procedure
// returns an object containing the value in the 1x1 resultset generated by the command
//
//*********************************************************************
public static object ExecuteScalar(string connectionString, string spName, params object[] parameterValues)
{
//if we receive parameter values, we need to figure out where they go
if ((parameterValues != null) && (parameterValues.Length > 0))
{
//pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);
//assign the provided values to these parameters based on parameter order
AssignParameterValues(commandParameters, parameterValues);
//call the overload that takes an array of SqlParameters
return ExecuteScalar(connectionString, CommandType.StoredProcedure, spName, commandParameters);
}
//otherwise we can just call the SP without params
else
{
return ExecuteScalar(connectionString, CommandType.StoredProcedure, spName);
}
}
//*********************************************************************
//
// Execute a SqlCommand (that returns a 1x1 resultset) against the specified SqlConnection
// using the provided parameters.
//
// e.g.:
// int orderCount = (int)ExecuteScalar(conn, CommandType.StoredProcedure, "GetOrderCount", new SqlParameter("@prodid", 24));
//
// param name="connection" a valid SqlConnection
// param name="commandType" the CommandType (stored procedure, text, etc.)
// param name="commandText" the stored procedure name or T-SQL command
// param name="commandParameters" an array of SqlParamters used to execute the command
// returns an object containing the value in the 1x1 resultset generated by the command
//
//*********************************************************************
public static object ExecuteScalar(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
{
//create a command and prepare it for execution
SqlCommand cmd = new SqlCommand();
PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters);
//execute the command & return the results
object retval = cmd.ExecuteScalar();
// detach the SqlParameters from the command object, so they can be used again.
cmd.Parameters.Clear();
return retval;
}
}
//*********************************************************************
//
// SqlHelperParameterCache provides functions to leverage a static cache of procedure parameters, and the
// ability to discover parameters for stored procedures at run-time.
//
//*********************************************************************
public sealed class SqlHelperParameterCache
{
//*********************************************************************
//
// Since this class provides only static methods, make the default constructor private to prevent
// instances from being created with "new SqlHelperParameterCache()".
//
//*********************************************************************
private SqlHelperParameterCache() {}
private static Hashtable paramCache = Hashtable.Synchronized(new Hashtable());
//*********************************************************************
//
// resolve at run time the appropriate set of SqlParameters for a stored procedure
//
// param name="connectionString" a valid connection string for a SqlConnection
// param name="spName" the name of the stored procedure
// param name="includeReturnValueParameter" whether or not to include their return value parameter
//
//*********************************************************************
private static SqlParameter[] DiscoverSpParameterSet(string connectionString, string spName, bool includeReturnValueParameter)
{
using (SqlConnection cn = new SqlConnection(connectionString))
using (SqlCommand cmd = new SqlCommand(spName,cn))
{
cn.Open();
cmd.CommandType = CommandType.StoredProcedure;
SqlCommandBuilder.DeriveParameters(cmd);
if (!includeReturnValueParameter)
{
cmd.Parameters.RemoveAt(0);
}
SqlParameter[] discoveredParameters = new SqlParameter[cmd.Parameters.Count];;
cmd.Parameters.CopyTo(discoveredParameters, 0);
return discoveredParameters;
}
}
private static SqlParameter[] CloneParameters(SqlParameter[] originalParameters)
{
//deep copy of cached SqlParameter array
SqlParameter[] clonedParameters = new SqlParameter[originalParameters.Length];
for (int i = 0, j = originalParameters.Length; i < j; i++)
{
clonedParameters[i] = (SqlParameter)((ICloneable)originalParameters[i]).Clone();
}
return clonedParameters;
}
//*********************************************************************
//
// add parameter array to the cache
//
// param name="connectionString" a valid connection string for a SqlConnection
// param name="commandText" the stored procedure name or T-SQL command
// param name="commandParameters" an array of SqlParamters to be cached
//
//*********************************************************************
public static void CacheParameterSet(string connectionString, string commandText, params SqlParameter[] commandParameters)
{
paramCache[hashKey] = commandParameters;
}
//*********************************************************************
//
// Retrieve a parameter array from the cache
//
// param name="connectionString" a valid connection string for a SqlConnection
// param name="commandText" the stored procedure name or T-SQL command
// returns an array of SqlParamters
//
//*********************************************************************
public static SqlParameter[] GetCachedParameterSet(string connectionString, string commandText)
{
string hashKey = connectionString + ":" + commandText;
SqlParameter[] cachedParameters = (SqlParameter[])paramCache[hashKey];
if (cachedParameters == null)
{
return null;
}
else
{
return CloneParameters(cachedParameters);
}
}
//*********************************************************************
//
// Retrieves the set of SqlParameters appropriate for the stored procedure
//
// This method will query the database for this information, and then store it in a cache for future requests.
//
// param name="connectionString" a valid connection string for a SqlConnection
// param name="spName" the name of the stored procedure
// returns an array of SqlParameters
//
//*********************************************************************
public static SqlParameter[] GetSpParameterSet(string connectionString, string spName)
{
return GetSpParameterSet(connectionString, spName, false);
}
//*********************************************************************
//
// Retrieves the set of SqlParameters appropriate for the stored procedure
//
// This method will query the database for this information, and then store it in a cache for future requests.
//
// param name="connectionString" a valid connection string for a SqlConnection
// param name="spName" the name of the stored procedure
// param name="includeReturnValueParameter" a bool value indicating whether the return value parameter should be included in the results
// returns an array of SqlParameters
//
//*********************************************************************
public static SqlParameter[] GetSpParameterSet(string connectionString, string spName, bool includeReturnValueParameter)
{
string hashKey = connectionString + ":" + spName + (includeReturnValueParameter ? ":include ReturnValue Parameter":"");
SqlParameter[] cachedParameters;
cachedParameters = (SqlParameter[])paramCache[hashKey];
if (cachedParameters == null)
{
cachedParameters = (SqlParameter[])(paramCache[hashKey] = DiscoverSpParameterSet(connectionString, spName, includeReturnValueParameter));
}
return CloneParameters(cachedParameters);
}
}
}
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