WebService question

savoym · April 26th, 2004, 07:53 AM

In one of the web methods I have within my web service I have the following code:

public void DeleteRecords( int intRecordID )
{
//Make sure the user is authenticated before running this WEB METHOD.
if (securityTicket.IsTicketValid(sessnID) == true)
{
return "Authenticated";
}
else
{
return "Failed To Authenticate";
}

// Get a connection to the database.
SqlConnection dbConnection = new SqlConnection();
dbConnection = XXX.UUU.Database.GetDBConnection();

// Create a command object.
SqlCommand dbCommand = new SqlCommand();

// Set up the properties for the command and connection objects.
dbCommand.Connection = dbConnection;
dbCommand.CommandType = CommandType.StoredProcedure;
dbCommand.CommandText = "Delete_Records";

// Variable Name (Input)
dbCommand.Parameters.Add("@RecordID", SqlDbType.Int);
dbCommand.Parameters["@RecordID"].Direction = ParameterDirection.Input;
dbCommand.Parameters["@RecordID"].Value = aintRecordid;

// Execute the stored procedure.
dbCommand.ExecuteNonQuery();

// Close the connection to the database.
dbCommand.Connection.Close();
}

How do I add a try catch and throw to this code since the method returns a void? Is there some other way that is better to handle this type of code? I am trying to authenticate the user before they run this WebMethod.

Any suggestions or help would be appreciated. Thanks.

Imar · April 26th, 2004, 07:59 AM

There may be better ways, but one way I have used a couple of times is to return either a string or a DataSet from your method, even if it's a void type of method.

That way, the client can examine the DataSet or string, figure out what is going on and act accordingly....

Cheers,

Imar
---------------------------------------
Imar Spaanjaars
Everyone is unique, except for me.
While typing this post, I was listening to: Brother Wolf; Sister Moon by The Cult (Track 5 from the album: Love) What's This?

savoym · April 26th, 2004, 08:13 AM

Imar,

Thanks much. I'll try that. I just assumed that because this contains a stored proc. to only delete records and not report anything back then I thought we could only use VOID.

Thanks again. I'll reply back if I run into a problem.

Imar · April 26th, 2004, 08:23 AM

True. In other circumstances, that would be good enough (although even then you could have a return type of bool to indicate success or failure).

However, you can't really throw a useful error, so you need to return something that contains error information. The good thing about a DataSet is that you can return detailed, structured info. You could, for example, return a ErrorDescription, Number, Severity, a HelpURL with more info etc. Other .NET solutions can read and use the DataSet as a DataSet, other platforms can access it as a normal XML stream.

Cheers,

Imar
---------------------------------------
Imar Spaanjaars
Everyone is unique, except for me.
While typing this post, I was listening to: Bleeding heart by Jimi Hendrix (Track 10 from the album: Purple Haze) What's This?

savoym · April 26th, 2004, 09:54 AM

Having this code:

if (securityTicket.IsTicketValid(sessnID) == true)
{
return "Authenticated";
}
else
{
return "Failed To Authenticate";
}

in my web method denotes now this error:

Cannot implicitly convert type 'string' to 'System.Data.DataSet'

I did not see a CONVERT option. Any suggestions or help would again be appreciated.

Thank you.

Imar · April 26th, 2004, 10:18 AM

Yeah, that makes sense. When your method returns a DataSet, it should return a DataSet not a string. Also, you can't expect a string to be converted to a DataSet, as a DataSet contains meta data about itself. Try something like this:

Code:

if (securityTicket.IsTicketValid(sessnID) == true)
{
  // Construct DataSet with useful return stuff here
}
else
{
  DataTable MyErrorsTable = new DataTable("ReturnedErrors");
  MyErrorsTable.Columns.Add("ErrorMessage",System.Type.GetType("System.String"));
  MyErrorsTable.Columns.Add("ErrorNumber",System.Type.GetType("System.Int32"));
  DataRow MyDR = MyErrorsTable.NewRow();
  MyDR("ErrorMessage") = "Your Error Message Here";
  MyDR("ErrorNumber") = -100;
  MyErrorsTable.Rows.Add(MyDR);
  DataSet ErrorsDataSet = new DataSet("Errors");
  ErrorsDataSet.Tables.Add(MyErrorsTable);
  return ErrorsDataSet;
}

I am typing this right into P2P, so it may not compile at once. For a more detailed explanation of all this, look here: http://www.devx.com/dotnet/Article/20369/1954?pf=true

Alternatively, set up your method to return a string:

Code:

public string DeleteRecords( int intRecordID )
{

This way, the code you posted in your last message will work fine. However, the disadvantage is that you can only return a simple string, and no detailed information about the error.

HtH,

Imar
---------------------------------------
Imar Spaanjaars
Everyone is unique, except for me.
While typing this post, I was listening to: Give It Revolution by Suicidal Tendencies (Track 5 from the album: Lights, Camera, Revolution) What's This?

savoym · April 27th, 2004, 08:11 AM

Imar,

Again, thanks for your time and all your help. It is appreciated. I am building the try, catch statement.