Debug or Print Log in Windows Phone 8

System.Diagnostics.Debug.WriteLine("")

You can debug the native code in the windows phone Runtime Component by selecting the native debug engine for the UI Task. in this case you will also get the debug output.

to select the native debug engine for UI Task

1. Go to debug property page by right clicking on the project and selecting the "properties" menu followed by selecting the "Debug" tab.

2. Under the "UI Task" there is a drop down. select "Native Only"

Dismiss UIAlertViews or UIActionSheet When Enter Background State

- (void)checkViews:(NSArray *)subviews {
    Class AVClass = [UIAlertView class];
    Class ASClass = [UIActionSheet class];
    for (UIView * subview in subviews){
        if ([subview isKindOfClass:AVClass]){
            [(UIAlertView *)subview dismissWithClickedButtonIndex:[(UIAlertView *)subview cancelButtonIndex] animated:NO];
        } else if ([subview isKindOfClass:ASClass]){
            [(UIActionSheet *)subview dismissWithClickedButtonIndex:[(UIActionSheet *)subview cancelButtonIndex] animated:NO];
        } else {
            [self checkViews:subview.subviews];
        }
    }
}

Calling it from the applicationDidEnterBackground procedure

[self checkViews:application.windows];

Eliminate Extra separators below UITableView

- (CGFloat)tableView:(UITableView *)tableView heightForFooterInSection:(NSInteger)section {
     // This will create a "invisible" footer
     return 0.01f;
 }

- (UIView *)tableView:(UITableView *)tableView viewForFooterInSection:(NSInteger)section
{        
    return [UIView new];

    // If you are not using ARC:
    // return [[UIView new] autorelease];
}

Create UIColor from a Hex String

// Assumes input like "#00FF00" (#RRGGBB).
+ (UIColor *)colorFromHexString:(NSString *)hexString {
    unsigned rgbValue = 0;
    NSScanner *scanner = [NSScanner scannerWithString:hexString];
    [scanner setScanLocation:1]; // bypass '#' character
    [scanner scanHexInt:&rgbValue];
    return [UIColor colorWithRed:((rgbValue & 0xFF0000) >> 16)/255.0 green:((rgbValue & 0xFF00) >> 8)/255.0 blue:(rgbValue & 0xFF)/255.0 alpha:1.0];
}

UIImage resize (Scale proportion)

// grab the original image
UIImage *originalImage = [UIImage imageNamed:@"myImage.png"];
    
// scaling set to 2.0 makes the image 1/2 the size. 
UIImage *scaledImage = 
                [UIImage imageWithCGImage:[originalImage CGImage] 
                              scale:(originalImage.scale * 2.0)
                                 orientation:(originalImage.imageOrientation)];

Add Index to UITableViewController

- (NSArray *)sectionIndexTitlesForTableView:(UITableView *)tableView
{
    NSMutableArray *tempArray = [[NSMutableArray alloc] init];
    [tempArray addObject:@"{search}"]; //search icon
    [tempArray addObject:@"#"];
    [tempArray addObject:@"A"];
    [tempArray addObject:@"B"];
    [tempArray addObject:@"C"];
    [tempArray addObject:@"D"];
    [tempArray addObject:@"E"];
    [tempArray addObject:@"F"];
    [tempArray addObject:@"G"];
    [tempArray addObject:@"H"];
    [tempArray addObject:@"I"];
    [tempArray addObject:@"J"];
    [tempArray addObject:@"K"];
    [tempArray addObject:@"L"];
    [tempArray addObject:@"M"];
    [tempArray addObject:@"N"];
    [tempArray addObject:@"O"];
    [tempArray addObject:@"P"];
    [tempArray addObject:@"Q"];
    [tempArray addObject:@"R"];
    [tempArray addObject:@"S"];
    [tempArray addObject:@"T"];
    [tempArray addObject:@"U"];
    [tempArray addObject:@"V"];
    [tempArray addObject:@"W"];
    [tempArray addObject:@"X"];
    [tempArray addObject:@"Y"];
    [tempArray addObject:@"Z"];
    return tempArray;
}

- (NSInteger)tableView:(UITableView *)tableView sectionForSectionIndexTitle:(NSString *)title atIndex:(NSInteger)index
{
    NSLog(@"click %@", title);
    return 0; 
}

Play sound without disabling ipod playback

#import <AVFoundation/AVAudioSession.h>
#import <AudioToolbox/AudioToolbox.h>

// Set the AVAudio Session property
AVAudioSession *session = [AVAudioSession sharedInstance];
[session setCategory:AVAudioSessionCategoryPlayback error:nil];
OSStatus propertySetError = 0;
UInt32 allowMixing = true;
propertySetError = AudioSessionSetProperty (
      kAudioSessionProperty_OverrideCategoryMixWithOthers,
      sizeof (allowMixing),
      &allowMixing
);
NSError *activationError = nil;
[session setActive:YES error:&activationError];
// Now play the sound in filePath
NSURL *fileUrl = [NSURL fileURLWithPath:filePath];
NSError *error;
AVAudioPlayer *player = [[[AVAudioPlayer alloc] initWithContentsOfURL:fileUrl error:&;error]autorelease];

Number of days in the current month

NSDate *today = [NSDate date]; //Get a date object for today's date
NSCalendar *c = [NSCalendar currentCalendar];
NSRange days = [c rangeOfUnit:NSDayCalendarUnit 
                       inUnit:NSMonthCalendarUnit 
                      forDate:today];

NSLog(@"number of days: %d",  days.length);

Detect iPhone 4 inch

#define isPhone568 ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone && [UIScreen mainScreen].bounds.size.height == 568)
#define iPhone568ImageNamed(image) (isPhone568 ? [NSString stringWithFormat:@"%@-568h.%@", [image stringByDeletingPathExtension], [image pathExtension]] : image)
#define iPhone568Image(image) ([UIImage imageNamed:iPhone568ImageNamed(image)])

UIImage *image = [UIImage imageNamed:iPhone568ImageNamed(@"Default.png")];

Detect Retina Display

#define IS_RETINA ([[UIScreen mainScreen] respondsToSelector:@selector(displayLinkWithTarget:selector:)] && ([UIScreen mainScreen].scale == 2.0))

if(IS_RETINA)
{
   // Retina display
} else {
  // non-Retina display

}