Call .Net web service from Objective C

(please correct the coding case in your XCODE) Here is the code you need to implement in any of your functions: -(void) viewDidLoad{}

• First you need to call the web service and then some of its delegates.
• Second, when you get the data, you have to parse it, because the data comes in XML format, so use XML parse (NSXMLparser).
• Once you have the data, you can display it or whatever.

Below is a sample code to return a HELLO WORLD string from a web service:

- (void)viewDidload
{
    NSMutableString *soapMessage = [NSMutableString stringWithFormat:@"<?xml version=\"1.0\"encoding=\"utf-8\"?>\n"
        "<soap:Envelope xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\">\n"
        "<soap:Body>\n"
        "<HelloWorld xmlns=\"http://Helloworldservice.org/\" />\n"
        "</soap:Body>\n"
        "</soap:Envelope>"];

    //You can get soap Message from web service simply when you run it it shows the request message and response message in XML format copy request message then paste it in XCODE. (Notice please check for escape sequence that is \")

    // The URL of the your web service  
    NSURL *url = [NSURL URLWithString:@"http://Helloworldservice/service.asmx"];  

    NSMutableURLRequest *theRequest = [NSMutableURLRequest requestWithURL:url]; 

    NSString *msgLength = [NSString stringWithFormat:@"%d", [soapMessage length]];  

    [theRequest addValue: @"text/xml; charset=utf-8" forHTTPHeaderField:@"Content-Type"];

    [theRequest addValue: @"http://HelloWorld.org/HelloWorld" forHTTPHeaderField:@"Soapaction"];

    [theRequest addValue: msgLength forHTTPHeaderField:@"Content-Length"];
    [theRequest setHTTPMethod:@"POST"];     
    [theRequest setHTTPBody: [soapMessage dataUsingEncoding:NSUTF8StringEncoding]];

    NSURLConnection *theConnection = [[NSURLConnection alloc] initWithRequest:theRequest delegate:self];

    if (theConnection) //Means if the connection is active
    {
    }
    else
    {
        NSLog(@"theConnection is NULL");
    }
}

//NOW You have to implement some of delegates required for connection

//Recieve data defined when your connection do recieve some data from .NET web service.

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
    NSString* strin=[[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];
    //Now as we get data in XML format time to parse the data into some meaningful form use NSXMLPARSER.
    NSXMLParser *parser=[[NSXMLParser alloc]initWithData:data];

    //Delegate should be defined as now make it self it will probably give a warning message so execute it no problem but if u want this warning to be removed just ass delegate in .h file like @interface Web_Service_testViewController : UIViewController<NSXMLParserDelegate> {}

    [parser setDelegate:self];
    //here actual parsing is done.
    [parser parse];
    //Now time to release parse object from memory.
    [parser release];
}

//If connection fails just in case OK.
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error{}

    //Called when connection has finished. Mostly we place the data in this delegate we require to be called after web service i hope it is understandable to u :-)

- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    [connection release];   
}

//Now we have to implement some of the delegates of NSXMLPARSER Quite simple

//For a file reading.
- (void)parserDidStartDocument:(NSXMLParser *)parser{
}

//When parsing is started on the element obtained from web service for the moment leave it blank. 
- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict
{
}

//When parsing is finished.
- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName
{
}

//This is the main delegate that can return a string format result.
- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)astring
{
    //Say you have a NSString object named as "mymessage"
    mymessage=string;
    //this "astring" is that string which is returned from delegate
}

//Your web service is finished it is totally implemented code no errors :-). Quite easy isn't it?