WebServices (C #)-return data set query (Dataset)

[Webmethod (description = "function: Return query dataset | parameter: SQL query | return: DataSet | return type: DataSet")]
Public dataset getdataset (string strsql)
{
// Database connection parameters (access to the client application configuration file)
String strconn = @ configurationmanager. connectionstrings ["myconnectionstring"]. connectionstring;
// Create an open connection to the database
// Set to open the database connection
Sqlconnection myconn = new sqlconnection (strconn );
Try // run properly
{
String MySQL = @ strsql. Trim (). tostring ();
// Use the attribute setting specified by connectionstring to open the database connection
Myconn. open ();
// An SQL statement or stored procedure to be executed on the database
Sqlcommand mycomm = new sqlcommand (MySQL, myconn );
// A set of data commands and a database connection, used to fill the dataset and update the data source
Sqldataadapter myadapter = new sqldataadapter ();
// Data cache in memory
Dataset mydataset = new dataset ();
// Query the database
Myadapter. selectcommand = new sqlcommand (strsql, myconn );
// Add or refresh rows in dataset to match rows in the data source
Myadapter. Fill (mydataset );
// Return Dataset
Return mydataset;
}
Catch (sqlexception) // Exception Handling for database operations
{
Console. Write ("<script language = JavaScript> ");
Console. Write ("alert ('system prompt: the current database operation failed or the network is busy. Please try again later! ');");
Console. Write ("</SCRIPT> ");
If (myconn. State = connectionstate. open)
{
// Close the database connection
Myconn. Close ();
}
// Failed to return
Return NULL;
}
Catch // Exception Handling
{
If (myconn. State = connectionstate. open)
{
// Close the database connection
Myconn. Close ();
}
// Failed to return
Return NULL;
}
Finally // clear all resources allocated in the try block after execution
{
If (myconn. State = connectionstate. open)
{
// Close the database connection
Myconn. Close ();
}
}
}