how to attatch a file to the mail using default mail composer

i hav a file with some data and i want to attach this file to mail, and i am using the default mail composer ...

any idea how to attach the file to mail before sending to receip开发者_运维百科ents....

Thanks in advance....

Example with an attached image:

NSData *myData = UIImagePNGRepresentation(myImage);
[mailComposer addAttachmentData:myData mimeType:@"image/png" fileName:@"MyImage"];

NSString *path = [[NSBundle mainBundle] pathForResource:@"bg" ofType:@"jpg"];

NSData *myData = [NSData dataWithContentsOfFile:path];

[controller addAttachmentData:myData mimeType:@"image/jpg" fileName:@"Attachment-1"];
[self presentModalViewController:controller animated:YES];