Develop Reference

Toolbar badge count is not working when I tried to set it programmatically from ViewModel

I have made dependency services on both side and Interface in shared library on Xamarin platform
when i use it in xaml.cs hard coded it works but when i use it in ViewModel using messaging center to set count of notification in Toolbar of application it doesn't works
Does anyone have any kind of idea whats happening or should i do ?
this code works from Xaml.cs page
DependencyService.Get<IToolbarItemBadgeService>().SetBadge(this, ToolbarItems[0], "2", Color.Red, Color.White);
And Below Code doesn't works
From ViewModel
" MessagingCenter.Send(new MessagingCenterModel { }, "NotificationCount", NotificationListCount);
At Xaml.cs Page
MessagingCenter.Subscribe<MessagingCenterModel, string>(this, "NotificationCount", (sender, args) =>
{
DependencyService.Get<IToolbarItemBadgeService>().SetBadge(this, ToolbarItems[0], args, Color.Red, Color.White);
});
InterFaceCode
public interface IToolbarItemBadgeService
{
void SetBadge(Page page, ToolbarItem item, string value, Color backgroundColor, Color textColor);
}
Dependency service
public class ToolbarItemBadgeService : IToolbarItemBadgeService
{
public void SetBadge(Page page, ToolbarItem item, string value, Color backgroundColor, Color textColor)
{
Device.BeginInvokeOnMainThread(() =>
{
var toolbar = CrossCurrentActivity.Current.Activity.FindViewById(Resource.Id.toolbar) as Android.Support.V7.Widget.Toolbar;
if (toolbar != null)
{
if (!string.IsNullOrEmpty(value))
{
var idx = page.ToolbarItems.IndexOf(item);
if (toolbar.Menu.Size() > idx)
{
var menuItem = toolbar.Menu.GetItem(idx);
BadgeDrawable.SetBadgeText(CrossCurrentActivity.Current.Activity, menuItem, value, backgroundColor.ToAndroid(), textColor.ToAndroid());
}
}
}
});
}
}
BadgeDrawable Class
public class BadgeDrawable : Drawable
{
private const string BadgeValueOverflow = "*";
private Paint _badgeBackground;
private Paint _badgeText;
private Rect _textRect = new Rect();
private string _badgeValue = "";
private bool _shouldDraw = true;
Context _context;
public override int Opacity => (int)Format.Unknown;
public BadgeDrawable(Context context, Color backgroundColor, Color textColor)
{
_context = context;
float textSize = context.Resources.GetDimension(Resource.Dimension.textsize_badge_count);
_badgeBackground = new Paint();
_badgeBackground.Color = backgroundColor;
_badgeBackground.AntiAlias = true;
_badgeBackground.SetStyle(Paint.Style.Fill);
_badgeText = new Paint();
_badgeText.Color = textColor;
_badgeText.SetTypeface(Typeface.Default);
_badgeText.TextSize = textSize;
_badgeText.AntiAlias = true;
_badgeText.TextAlign = Paint.Align.Center;
}
public override void Draw(Canvas canvas)
{
if (!_shouldDraw)
{
return;
}
Rect bounds = Bounds;
float width = bounds.Right - bounds.Left;
float height = bounds.Bottom - bounds.Top;
float oneDp = 1 * _context.Resources.DisplayMetrics.Density;
// Position the badge in the top-right quadrant of the icon.
float radius = ((Java.Lang.Math.Max(width, height) / 2)) / 2;
float centerX = (width - radius - 1) + oneDp * 2;
float centerY = radius - 2 * oneDp;
canvas.DrawCircle(centerX, centerY, (int)(radius + oneDp * 5), _badgeBackground);
// Draw badge count message inside the circle.
_badgeText.GetTextBounds(_badgeValue, 0, _badgeValue.Length, _textRect);
float textHeight = _textRect.Bottom - _textRect.Top;
float textY = centerY + (textHeight / 2f);
canvas.DrawText(_badgeValue.Length > 2 ? BadgeValueOverflow : _badgeValue,
centerX, textY, _badgeText);
}
// Sets the text to display. Badge displays a '*' if more than 2 characters
private void SetBadgeText(string text)
{
_badgeValue = text;
// Only draw a badge if the value isn't a zero
_shouldDraw = !text.Equals("0");
InvalidateSelf();
}
public override void SetAlpha(int alpha)
{
// do nothing
}
public override void SetColorFilter(ColorFilter cf)
{
// do nothing
}
public static void SetBadgeCount(Context context, IMenuItem item, int count, Color backgroundColor, Color textColor)
{
SetBadgeText(context, item, $"{count}", backgroundColor, textColor);
}
public static void SetBadgeText(Context context, IMenuItem item, string text, Color backgroundColor, Color textColor)
{
if (item.Icon == null)
{
return;
}
BadgeDrawable badge = null;
Drawable icon = item.Icon;
if (item.Icon is LayerDrawable)
{
LayerDrawable lDrawable = item.Icon as LayerDrawable;
if (string.IsNullOrEmpty(text) || text == "0")
{
icon = lDrawable.GetDrawable(0);
lDrawable.Dispose();
}
else
{
for (var i = 0; i < lDrawable.NumberOfLayers; i++)
{
if (lDrawable.GetDrawable(i) is BadgeDrawable)
{
badge = lDrawable.GetDrawable(i) as BadgeDrawable;
break;
}
}
if (badge == null)
{
badge = new BadgeDrawable(context, backgroundColor, textColor);
icon = new LayerDrawable(new Drawable[] { item.Icon, badge });
}
}
}
else
{
badge = new BadgeDrawable(context, backgroundColor, textColor);
icon = new LayerDrawable(new Drawable[] { item.Icon, badge });
}
badge?.SetBadgeText(text);
item.SetIcon(icon);
icon.Dispose();
}
}

Firstly , make sure that we had Subscribe the message before we send it . Otherwise the codes in Subscribe will never been called .
In addition , the code in Dependency Service could only set the badge of ToolbarItem in the navigation bar (on tabbed bar it will never work).
If you want to set the badge of tabbed page icon , you could use the plugin Plugin.Badge .

Memory Leaks : ListView with Bitmaps

I have a clearly memory leak problem and I need some help/advices to solve it.
My scenario has a simple ListView that displays image and title. This image is a bitmap Image downloaded from server.
After scrolling up and down so FAST this ListView crashes my app, and if i inspect the console i have a OOM Exception like that:
[art] Clamp target GC heap from 111MB to 96MB
[art] Alloc concurrent mark sweep GC freed 3(96B) AllocSpace objects, 0(0B) LOS objects, 0% free, 95MB/96MB, paused 1.187ms total 38.840ms
To avoid that OOM i implemented a LRUCache and DiskCache for store downloaded bitmaps into device, and get this files instead download images again.
This is my ListView Adapter:
public class LazyLoadAdapter : BaseAdapter
{
Activity _activity;
List _products;
BitmapCache cache;
ImageView _imgView;
Dictionary<string, Task> pendingFetch = new Dictionary<string, Task> ();
Bitmap NoMapPicture;
public LazyLoadAdapter(Activity activity, List<CouponExchange> products)
{
_activity = activity;
_products = products;
NoMapPicture = PrepareNoMapPicture (Resource.Drawable.default_coupon);
this.cache = BitmapCache.CreateCache (activity, "MapCache");
}
public override int Count
{
get { return _products.Count; }
}
public override Java.Lang.Object GetItem(int position)
{
return position;
}
public override long GetItemId(int position)
{
return position;
}
public override Android.Views.View GetView(int position, Android.Views.View convertView, Android.Views.ViewGroup parent)
{
if (convertView == null)
{
convertView = _activity.LayoutInflater.Inflate(Resource.Layout.ShopItemList, parent, false);
}
CouponExchange product = _products[position];
TextView txtProductName = convertView.FindViewById<TextView>(Resource.Id.textView24);
txtProductName.Text = product.CouponTitle;
TextView txtProductCost = convertView.FindViewById<TextView>(Resource.Id.textView24b);
txtProductCost.Text = product.Cost.ToString();
_imgView = convertView.FindViewById<ImageView>(Resource.Id.imgProduct);
GetPersonPicture (product.CouponImageUrl);
return convertView;
}
Bitmap DownloadoCacher (string url)
{
Bitmap map = null;
using(map){
map = cache.TryGet2 (url);
if (map!=null)
return map;
byte[] bytes;
using (var wc = new WebClient ()) {
bytes = wc.DownloadData (url);
};
if (bytes != null && bytes.Length > 0) {
BitmapFactory.Options options = new BitmapFactory.Options();
options.InJustDecodeBounds = true;
map = DecodeSampledBitmapFromResource (bytes, 400, 200);
} else {
return map;
}
cache.AddOrUpdate (url, map, TimeSpan.FromDays (1));
return map;
};
}
public static Bitmap DecodeSampledBitmapFromResource(byte[] bytes,
int reqWidth, int reqHeight) {
// First decode with inJustDecodeBounds=true to check dimensions
BitmapFactory.Options options = new BitmapFactory.Options();
options.InJustDecodeBounds = true;
BitmapFactory.DecodeByteArray(bytes, 0, bytes.Length, options);
// Calculate inSampleSize
options.InSampleSize = CalculateInSampleSize(options, reqWidth, reqHeight);
// Decode bitmap with inSampleSize set
options.InJustDecodeBounds = false;
return BitmapFactory.DecodeByteArray(bytes, 0, bytes.Length, options);
}
public static int CalculateInSampleSize(
BitmapFactory.Options options, int reqWidth, int reqHeight) {
// Raw height and width of image
int height = options.OutHeight;
int width = options.OutWidth;
int inSampleSize = 1;
if (height > reqHeight || width > reqWidth) {
int halfHeight = height / 2;
int halfWidth = width / 2;
// Calculate the largest inSampleSize value that is a power of 2 and keeps both
// height and width larger than the requested height and width.
while ((halfHeight / inSampleSize) > reqHeight
&& (halfWidth / inSampleSize) > reqWidth) {
inSampleSize *= 2;
}
}
return inSampleSize;
}
Bitmap PrepareNoMapPicture (int baseImage)
{
return BitmapFactory.DecodeResource (_activity.Resources, baseImage);
}
Bitmap GetPersonPicture (string url){
if (_imgView == null)
return null;
Bitmap map = null;
using (map) {
map = cache.TryGet2 (url);
if (map!=null) {
_imgView.SetImageBitmap (map);
} else {
_imgView.SetImageBitmap (NoMapPicture);
Action doMapSetting = () => {
_activity.RunOnUiThread (() => {
if (map == null){
map = cache.TryGet2 (url);
}
_imgView.SetImageBitmap (map);
});
};
if (pendingFetch.ContainsKey (url))
pendingFetch [url].ContinueWith (t => doMapSetting (), TaskContinuationOptions.ExecuteSynchronously);
else
pendingFetch[url] = SerialScheduler.Factory.StartNew (() => {
map = DownloadoCacher (url);
doMapSetting ();
});
}
return map;
};
}
Once images are downloaded, my cache gets images from device file.
After scroll up and down so fast, cacheDisk try get images from files and throws OOM Exception:
try {
bmp = Android.Graphics.BitmapFactory.DecodeFile (Path.Combine (basePath, key));
} catch (Exception e) {
var err = e.Message;
return null;
}
All replies would be appreciate. Thanks you

I use this Picasso Binding library for Xamarin :
https://github.com/jacksierkstra/Picasso
This powerful image downloading and caching library allows you to simplify your Image management.
Official documentation :
http://square.github.io/picasso/
Hope this helps

How to Rearrange rectangles on canvas after modifying height of any rectangle in wpf?

I am adding Rectangle from grid cell values that is being entered by user directly in grid rows. When i modify value of specific column say Thickness i.e Height then then it increases Height of selected row rectangle but it doesnt rearrange all rectangle below it exactly after the selected row rectangle.
In xaml.cs
public class MyLayer : INotifyPropertyChanged
{
public string Thickness { get; set; }
public string OffsetRight { get; set; }
public string OffsetLeft { get; set; }
public string Material { get; set; }
public string MaterialPopup { get; set; }
public Rectangle rectangle { get; set; }
public GlassRectangle GlassRectangle { get; set; }
public MaterialLayer()
{
GlassRectangle = new GlassRectangle();
}
event PropertyChangedEventHandler INotifyPropertyChanged.PropertyChanged
{
add { }
remove { }
}
}
public class GlassRectangle
{
public Rectangle Rectangle { get; set; }
public double Top = 0;
public GlassRectangle()
{
Rectangle = new Rectangle();
}
}
private void gridInner_CellValueChanged(object sender, DevExpress.Xpf.Grid.CellValueChangedEventArgs e)
{
string cellValue = string.Empty;
MyLayer currentLayer = ((MyLayer)(e.Row));
if (e.Column.HeaderCaption.ToString() == "Thickness")
{
cellValue =(e.Value.ToString());
//there is alredy a rectangle - means this is edit mode
if (currentLayer.rectangle != null)
{
currentLayer.rectangle.Height = Convert.ToDouble(cellValue);
currentLayer.rectangle.Stroke = new SolidColorBrush(Color.FromRgb(0, 255, 0));
}
//else this is insert mode
else
{
currentLayer.rectangle = CreateRectangle(cellValue);
}
}
}
protected Rectangle CreateRectangle(string cellval)
{
Rectangle newrect = new Rectangle();
newrect.Stroke = Brushes.Red;
newrect.StrokeThickness = 1;
if (cellval.ToString().Contains("."))
{
newrect.Height = Convert.ToDouble(cellval) * 100;
}
else
{
newrect.Height = Convert.ToDouble(cellval);
}
newrect.Width = width;
Canvas.SetLeft(newrect, 100);
double canvasTop = 0.0;
if (canvasboard.Children.Count > 0)
{
var lastChildIndex = canvasboard.Children.Count - 1;
var lastChild = canvasboard.Children[lastChildIndex] as FrameworkElement;
if (lastChild != null)
//lastChild.Height-1: so that it come extactly on existing if set to +1 it comes below first rectangle
canvasTop = Canvas.GetTop(lastChild) + lastChild.Height - 1;
}
Canvas.SetTop(newrect, canvasTop);
val = val + 1;
newrect.Tag = val;
canvasboard.Children.Add(newrect);
//rectangle = rect;
foreach (UIElement ui in canvasboard.Children)
{
if (ui.GetType() == typeof(Rectangle))
{
itemstoremove.Add(ui);
}
}
return newrect;
}
NEW EVENT Method:
private void gridMaterialInner_CellValueChanged(object sender, DevExpress.Xpf.Grid.CellValueChangedEventArgs e)
{
string cellValue = string.Empty;
string cellOldValue = string.Empty;
MyLayer currentLayer = ((MyLayer)(e.Row));
if (e.Column.HeaderCaption.ToString() == "Thickness")
{
//current cell value
cellValue =(e.Value.ToString());// GetRowCellValue(e.RowHandle, gridMaterialInner.Columns["LastName"]).ToString();
//there is alredy a rectangle - means this is edit mode
double currentheight = 0.0;
double oldht = 0.0;
// old cell value
if (e.OldValue != null)
{
cellOldValue = (e.OldValue.ToString());
}
if (currentLayer.rectangle != null)
{
if (cellValue.ToString().Contains("."))
{
currentheight = Convert.ToDouble(cellValue) * 100;
}
else
{
currentheight = Convert.ToDouble(cellValue) * 100;
}
if (cellOldValue.ToString().Contains("."))
{
oldht = Convert.ToDouble(cellOldValue) * 100;
}
else if(cellOldValue!=string.Empty)
{
oldht = Convert.ToDouble(cellOldValue) * 100;
}
currentLayer.rectangle.Height = currentheight;
currentLayer.rectangle.Stroke = new SolidColorBrush(Color.FromRgb(0, 255, 0));
//Refresh();
//Get the index of selected row
int layerIndex = materialBindlist.IndexOf(currentLayer);
for(int i = layerIndex; i < materialBindlist.Count-1; i++)
{
//set the top position of all other rectangles that are below selected rectangle/row
//(Current-Old)+Top
Canvas.SetTop(materialBindlist[i + 1].rectangle, (currentheight - oldht) + materialBindlist[i + 1].GlassRectangle.Top);
//Canvas.SetTop(materialBindlist[i].rectangle, (currentheight - oldht) + materialBindlist[i + 1].GlassRectangle.Top);
}
}
//else this is insert mode
else
{
//MaterialLayer object
currentLayer.rectangle = CreateRectangle(cellValue);
//store Top & Rectangle object in GlassRectangle class which is referenced in MaterialLayer class
currentLayer.GlassRectangle.Rectangle = currentLayer.rectangle;
currentLayer.GlassRectangle.Top = canvasTop;
}
}
}
This create rectangle one after other like Stacked item on canvas. But when i modify the value of Thickness column which is Height of Rectangle it reflects on canvas but the Other Rectangle below must appear after the Changed Height of current rectangle.
Note: I cant use WrapPanel in my application. Just to modify existing code using Canvas.
Help Appreciated!
Modified For Loop in CellChange Event:
int layerIndex = materialBindlist.IndexOf(currentLayer);
for(int i = layerIndex; i < materialBindlist.Count-1; i++)
{
//set the top position of all other rectangles that are below selected rectangle/row
//(Current-Old)+Top
double top=Convert.ToDouble((currentHeight - oldHeight) + materialBindlist[i + 1].GlassRectangle.Top);
Canvas.SetTop(materialBindlist[i + 1].rectangle,top);
materialBindlist[i + 1].GlassRectangle.Top = top;
}

What you're looking for can be done even with a Canvas however you should really consider using something like an ItemsControl for this.
Solution when forced to use Canvas:
private void Refresh() {
for (int i = 1; i < canvasboard.Children.Count; ++i) {
var currentElement = canvasboard.Children[i] as FrameworkElement;
var previousElement = canvasboard.Children[i - 1] as FrameworkElement;
if (currentElement == null || previousElement == null)
return;
var requiredTop = Canvas.GetTop(previousElement) + previousElement.Height - 1;
if (Math.Abs(Canvas.GetTop(currentElement) - requiredTop) > 0.0)
Canvas.SetTop(currentElement, requiredTop);
}
}
Now call this function "after" you change the size of an existing element in the Canvas and it will re-position the elements accordingly to suit the new dimension. In your code, it would be called from the gridInner_CellValueChanged(...) function after you set the new height in "edit" mode.
What you should try to do:
If your able to persuade whoever you need to and get to use something like an ItemsControl, this will be so much simpler.
say a rough example:
xaml could be:
<ItemsControl ItemsSource="{Binding Items}">
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<VirtualizingStackPanel Orientation="Vertical" />
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
</ItemsControl>
with Items declared as public ObservableCollection<Rectangle> Items { get; set; } in code.
Now your Add() function could just be:
private void Add() {
var rect = new Rectangle {
Stroke = Brushes.Red,
StrokeThickness = 1,
Height = Convert.ToDouble(txtheight.Text),
Width = 100
};
Items.Add(rect);
}
and as for updates when your editing existing control's that would be automatic in this case. There is no hard-coded positioning as the Layout container takes care of all that mess for you.
You can ofcourse switch the Items collection type to your own custom control type MyLayer and with it implementing INPC, changes would still continue to be automatic. You'd have to define a DataTemplate now to get your Item to be rendered but that's like 3 lines of work in just xaml.
You can also just work of the Items property directly when needing to tweak an exisiting control than having to reference the ItemsControl in code-behind. Binding's should take care of the updates to the view automatically.

Modified for loop in Cell Change Event:
int layerIndex = materialBindlist.IndexOf(currentLayer);
for(int i = layerIndex; i < materialBindlist.Count-1; i++)
{
//set the top position of all other rectangles that are below selected rectangle/row
//(Current-Old)+Top
double top=Convert.ToDouble((currentHeight - oldHeight) + materialBindlist[i + 1].GlassRectangle.Top);
Canvas.SetTop(materialBindlist[i + 1].rectangle,top);
materialBindlist[i + 1].GlassRectangle.Top = top;
}
it works now..!Thanks to all!

LockScreen.SetImageUri ArgumentException despite working Uri

I am having trouble setting the lock screen to an image, but I think it is not a problem with a Uri but rather with the image itself.
When I try to set the image to a downloaded image that has approximately the right size for the lockscreen it works, also when an image is not too big. But when I try to set the lockscreen image to a photo from the camera (Nokia Lumia 920) it gives me this Argument Exception.
My Code:
// From the StorageHelper class:
public async Task<bool> SavePhotoAsync(Photo photo, WriteableBitmap source, int height, int width)
{
return await Task.Run(() =>
{
try
{
lock (StorageLock)
{
ObservableCollection<Photo> observableCollection = photo.PhotoAlbum.Photos as ObservableCollection<Photo>;
if (observableCollection == null)
{
return false;
}
if (!IsolatedStorageFile.GetUserStoreForApplication().DirectoryExists(photo.PhotoAlbum.Name))
{
IsolatedStorageFile.GetUserStoreForApplication().CreateDirectory(photo.PhotoAlbum.Name);
}
string fileName = photo.PhotoAlbum.Name + "/" + observableCollection.IndexOf(photo).ToString(CultureInfo.InvariantCulture);
if (IsolatedStorageFile.GetUserStoreForApplication().FileExists(fileName))
{
IsolatedStorageFile.GetUserStoreForApplication().DeleteFile(fileName);
}
IsolatedStorageFileStream fileStream =
IsolatedStorageFile.GetUserStoreForApplication().CreateFile(fileName);
int targetWidth = 0;
int targetHeight = 0;
if (source.PixelWidth < width || source.PixelHeight < height)
{
targetWidth = source.PixelWidth;
targetHeight = source.PixelHeight;
}
else
{
if (source.PixelWidth > source.PixelHeight)
{
double percentage = ((double)height)/((double) source.PixelHeight);
targetHeight = height;
targetWidth = (int) (source.PixelWidth * percentage);
}
else
{
double percentage = ((double)width) / ((double)source.PixelWidth);
targetWidth = width;
targetHeight = (int)(source.PixelHeight * percentage);
}
}
source.SaveJpeg(fileStream, targetWidth, targetHeight, 0, 100);
fileStream.Close();
return true;
}
}
catch (Exception e)
{
return false;
}
});
}
// End of StorageHelper
// From my LockscreenManager class:
public static async void SetLockScreenImages()
{
LockScreenRequestResult result = await LockScreenManager.RequestAccessAsync();
if (result == LockScreenRequestResult.Granted)
{
Uri uri = null;
try
{
uri = LockScreen.GetImageUri();
}
catch (Exception)
{
}
List<Uri> uriList = await BuildUriList();
if (uriList.Count == 0)
{
return;
}
int index = 0;
if (uri != null && uriList.Any(uriEntry => uri.ToString() == uriEntry.ToString()))
{
index = (uriList.IndexOf(uri) + 1) % uriList.Count;
}
if (InterfaceProvider.GetIStorageService().FileExists(uriList[index]))
{
try
{
LockScreen.SetImageUri(uriList[index]);
}
catch (Exception)
{
}
}
}
}
// End of Lockscreenmanager class
You can ignore my try to shrink down the image, it didn't help (but the images are still saved correctly). What could I do?

How do I rotate a label in C#? [duplicate]

This question already has answers here:
C# vertical label in a Windows Forms
(9 answers)
Closed 9 years ago.
I want to show a label rotated 90 degrees (so I can put a bunch of them at the top of a table as the headings). Is there an easy way to do this?

You will need to write your own or use a custom control.
A The Code Project article you can start with is Customized Text - Orientated Controls in C# - Part I (Label Control). This contains extra functionality, so you should be able to trim it down if you'd like.
And here is some code from it that is of interest:
/// <summary>
/// This is a lable, in which you can set the text in any direction/angle
/// </summary>
#region Orientation
//Orientation of the text
public enum Orientation
{
Circle,
Arc,
Rotate
}
public enum Direction
{
Clockwise,
AntiClockwise
}
#endregion
public class OrientedTextLabel : System.Windows.Forms.Label
{
#region Variables
private double rotationAngle;
private string text;
private Orientation textOrientation;
private Direction textDirection;
#endregion
#region Constructor
public OrientedTextLabel()
{
//Setting the initial condition.
rotationAngle = 0d;
textOrientation = Orientation.Rotate;
this.Size = new Size(105,12);
}
#endregion
#region Properties
[Description("Rotation Angle"),Category("Appearance")]
public double RotationAngle
{
get
{
return rotationAngle;
}
set
{
rotationAngle = value;
this.Invalidate();
}
}
[Description("Kind of Text Orientation"),Category("Appearance")]
public Orientation TextOrientation
{
get
{
return textOrientation;
}
set
{
textOrientation = value;
this.Invalidate();
}
}
[Description("Direction of the Text"),Category("Appearance")]
public Direction TextDirection
{
get
{
return textDirection;
}
set
{
textDirection = value;
this.Invalidate();
}
}
[Description("Display Text"),Category("Appearance")]
public override string Text
{
get
{
return text;
}
set
{
text = value;
this.Invalidate();
}
}
#endregion
#region Method
protected override void OnPaint(PaintEventArgs e)
{
Graphics graphics = e.Graphics;
StringFormat stringFormat = new StringFormat();
stringFormat.Alignment = StringAlignment.Center;
stringFormat.Trimming = StringTrimming.None;
Brush textBrush = new SolidBrush(this.ForeColor);
//Getting the width and height of the text, which we are going to write
float width = graphics.MeasureString(text,this.Font).Width;
float height = graphics.MeasureString(text,this.Font).Height;
//The radius is set to 0.9 of the width or height, b'cos not to
//hide and part of the text at any stage
float radius = 0f;
if (ClientRectangle.Width<ClientRectangle.Height)
{
radius = ClientRectangle.Width *0.9f/2;
}
else
{
radius = ClientRectangle.Height *0.9f/2;
}
//Setting the text according to the selection
switch (textOrientation)
{
case Orientation.Arc:
{
//Arc angle must be get from the length of the text.
float arcAngle = (2*width/radius)/text.Length;
if(textDirection == Direction.Clockwise)
{
for (int i=0; i<text.Length; i++)
{
graphics.TranslateTransform(
(float)(radius*(1 - Math.Cos(arcAngle*i + rotationAngle/180 * Math.PI))),
(float)(radius*(1 - Math.Sin(arcAngle*i + rotationAngle/180*Math.PI))));
graphics.RotateTransform((-90 + (float)rotationAngle + 180*arcAngle*i/(float)Math.PI));
graphics.DrawString(text[i].ToString(), this.Font, textBrush, 0, 0);
graphics.ResetTransform();
}
}
else
{
for (int i=0; i<text.Length; i++)
{
graphics.TranslateTransform(
(float)(radius*(1 - Math.Cos(arcAngle*i + rotationAngle/180*Math.PI))),
(float)(radius*(1 + Math.Sin(arcAngle*i + rotationAngle/180*Math.PI))));
graphics.RotateTransform((-90 - (float)rotationAngle - 180*arcAngle*i/(float)Math.PI));
graphics.DrawString(text[i].ToString(), this.Font, textBrush, 0, 0);
graphics.ResetTransform();
}
}
break;
}
case Orientation.Circle:
{
if (textDirection == Direction.Clockwise)
{
for(int i=0;i<text.Length;i++)
{
graphics.TranslateTransform(
(float)(radius*(1 - Math.Cos((2*Math.PI/text.Length)*i + rotationAngle/180*Math.PI))),
(float)(radius*(1 - Math.Sin((2*Math.PI/text.Length)*i + rotationAngle/180*Math.PI))));
graphics.RotateTransform(-90 + (float)rotationAngle + (360/text.Length)*i);
graphics.DrawString(text[i].ToString(), this.Font, textBrush, 0, 0);
graphics.ResetTransform();
}
}
else
{
for(int i=0;i<text.Length;i++)
{
graphics.TranslateTransform(
(float)(radius*(1 - Math.Cos((2*Math.PI/text.Length)*i + rotationAngle/180*Math.PI))),
(float)(radius*(1 + Math.Sin((2*Math.PI/text.Length)*i + rotationAngle/180*Math.PI))));
graphics.RotateTransform(-90 - (float)rotationAngle - (360/text.Length)*i);
graphics.DrawString(text[i].ToString(), this.Font, textBrush, 0, 0);
graphics.ResetTransform();
}
}
break;
}
case Orientation.Rotate:
{
//For rotation, who about rotation?
double angle = (rotationAngle/180)*Math.PI;
graphics.TranslateTransform(
(ClientRectangle.Width+(float)(height*Math.Sin(angle))-(float)(width*Math.Cos(angle)))/2,
(ClientRectangle.Height-(float)(height*Math.Cos(angle))-(float)(width*Math.Sin(angle)))/2);
graphics.RotateTransform((float)rotationAngle);
graphics.DrawString(text,this.Font,textBrush,0,0);
graphics.ResetTransform();
break;
}
}
}
#endregion
}

You can also take a look at the Windows ToolStrip control. It has an option for TextDirection that can be set to Vertical90 or Vertical270 and this will rotate your Label text in the appropriate direction.
Overview: ToolStrip Class (MSDN)
Setting the property (learn.microsoft.com)
Enumerated Values (learn.microsoft.com)