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WPF WriteableBitmap drawing over loaded picture with mouse and save. Strange cursor shift

I'm trying to implement some WPF drawing sample to understand how it works. I can solve such task with C++ very quickly but I want to understand WPF means.
During the implementation of a task I faced with some strange problem: coordinates shift of mouse cursor responsible to pixels I can see on canvas.
First of all, my task is: load some picture from file; show it on Image component; allow to draw over image with mouse (like pencil tool); save changes to new file. Task is easy to implement.
Here is my code:
XAML:
<Window x:Class="MyPaint.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:MyPaint"
xmlns:xctk="http://schemas.xceed.com/wpf/xaml/toolkit"
Background="#FF000000"
mc:Ignorable="d"
Title="Strange Paint" Height="503.542" Width="766.281" Icon="icons/paint.png">
<Grid >
<Grid.ColumnDefinitions>
<ColumnDefinition Width="50"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="20"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Grid Grid.Column="0" Grid.Row="1" Width="Auto">
<StackPanel HorizontalAlignment="Left" Width="Auto" Background="{x:Null}">
<Button x:Name="arrowButton" Width="25" Height="25" HorizontalAlignment="Left" Click="ArrowButton_Click">
<Image Source="icons/arrow.png"/>
</Button>
<Button x:Name="selectorButton" Width="25" Height="25" Click="SelectorButton_Click" HorizontalAlignment="Left">
<Image Source="icons/select_selection_tool-128.png"/>
</Button>
<Button x:Name="clearButton" Width="25" Height="25" Click="ClearButton_Click" HorizontalAlignment="Left">
<Image Source="icons/clear.png"/>
</Button>
<Button x:Name="pencilButton" Width="25" Height="25" Click="PencilButton_Click" HorizontalAlignment="Left">
<Image Source="icons/pencil.png"/>
</Button>
<Button x:Name="fillButton" Width="25" Height="25" Click="FillButton_Click" HorizontalAlignment="Left">
<Image Source="icons/fill.png"/>
</Button>
<xctk:ColorPicker Width="50" Name="ClrPcker_Foreground" SelectedColorChanged="ClrPcker_Foreground_SelectedColorChanged">
</xctk:ColorPicker>
</StackPanel>
</Grid>
<Grid x:Name="drawingCanvas" Grid.Column="1" Grid.Row="1" MouseMove="paintImageCanvas_MouseMove" MouseLeave="PaintImageCanvas_MouseLeave" MouseLeftButtonUp="PaintImageCanvas_MouseLeftButtonUp">
<ScrollViewer Grid.Column="1" HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Auto">
<Canvas x:Name="scrCanvas" Width="{Binding ActualWidth, ElementName=paintImageCanvas}" Height="{Binding ActualHeight, ElementName=paintImageCanvas}" >
<Image x:Name="paintImageCanvas" HorizontalAlignment="Left" VerticalAlignment="Top" Stretch="UniformToFill" MouseDown="paintImageCanvas_MouseDown" MouseMove="paintImageCanvas_MouseMove">
</Image>
<Rectangle x:Name="Rect" Stroke="DarkOrange" Visibility="Collapsed" Fill="#77EEEEEE"></Rectangle>
</Canvas>
</ScrollViewer>
</Grid>
<StackPanel Grid.Row="0">
<Menu IsMainMenu="True" DockPanel.Dock="Top" Background="#FF000000">
<MenuItem Header="_File" Foreground="White" Background="#FF000000">
<MenuItem x:Name="newMenuItem" Header="_New" Background="#FF000000" Click="NewMenuItem_Click"/>
<MenuItem x:Name="openMenuItem" Header="_Open" Click="openMenuItem_Click" Background="#FF000000"/>
<MenuItem Header="_Close" Background="#FF000000"/>
<MenuItem Header="_Save" Background="#FF000000" Click="MenuItem_Click"/>
<MenuItem x:Name="exitMenuItem" Header="_Exit" Click="exitMenuItem_Click" Background="#FF000000"/>
</MenuItem>
</Menu>
<StackPanel></StackPanel>
</StackPanel>
</Grid>
Implementation of window class:
Class members:
Point currentPoint = new Point();
ToolBoxTypes currentSelectedTool = ToolBoxTypes.Unknown;
Color foregroundColor = Brushes.Black.Color;
WriteableBitmap imageWriteableBitmap;
Constructor and initialization (init white canvas 1024x768):
public MainWindow()
{
InitializeComponent();
ClrPcker_Foreground.SelectedColor = foregroundColor;
imageWriteableBitmap = BitmapFactory.New(1024, 768);
paintImageCanvas.Source = imageWriteableBitmap;
imageWriteableBitmap.Clear(Colors.White);
int i = 0;
}
Mouse down event (here I get the first point):
private void paintImageCanvas_MouseDown(object sender, MouseButtonEventArgs e)
{
if (e.ButtonState == MouseButtonState.Pressed)
{
currentPoint = e.GetPosition(paintImageCanvas);
}
if (currentSelectedTool == ToolBoxTypes.PencilTool)
{
}
}
Mouse move event (draw on canvas if pressed):
private void paintImageCanvas_MouseMove(object sender, MouseEventArgs e)
{
if (e.LeftButton == MouseButtonState.Pressed)
{
if(currentSelectedTool == ToolBoxTypes.PencilTool)
{
int x1 = Convert.ToInt32(currentPoint.X);
int y1 = Convert.ToInt32(currentPoint.Y);
int x2 = Convert.ToInt32(e.GetPosition(paintImageCanvas).X);
int y2 = Convert.ToInt32(e.GetPosition(paintImageCanvas).Y);
Console.WriteLine("Mouse X: " + x2 + " Mouse Y: " + y2);
imageWriteableBitmap.DrawLine( x1, y1, x2, y2, foregroundColor );
currentPoint = e.GetPosition(paintImageCanvas);
}
}
}
Ok. That's easy code.
And now, two usecases:
On start and init I can see white canvas and can draw with mouse without any problem (cursor follows pixels):
usecase 1
I loaded picture (size is 700x600) and got a problem, cursor has different place (can see a shift):
usecase 2
I think that problem is that canvas (Image) has different side than actual picture's side. I'm not sure.
Could you help me please to understand what is wrong and how to fix that?
Thanks.

Thanks to Dmitry (see comments on my question) the reason of the problem has been found: DPI of source picture.
I changed my code of picture loading and it works fine:
private void openMenuItem_Click(object sender, RoutedEventArgs e)
{
OpenFileDialog openFileDialog = new OpenFileDialog();
openFileDialog.Filter = "JPEG files (*.jpg)|*.jpg|PNG files (*.png)|*.png";
if (openFileDialog.ShowDialog() == true)
{
BitmapImage image = new BitmapImage(new Uri(openFileDialog.FileName));
imageWriteableBitmap = new WriteableBitmap(image);
double dpi = 96;
int width = imageWriteableBitmap.PixelWidth;
int height = imageWriteableBitmap.PixelHeight;
int stride = width * 4;
byte[] pixelData = new byte[stride * height];
imageWriteableBitmap.CopyPixels(pixelData, stride, 0);
BitmapSource bmpSource = BitmapSource.Create(width, height, dpi, dpi, PixelFormats.Bgra32, null, pixelData, stride);
imageWriteableBitmap = new WriteableBitmap(
bmpSource.PixelWidth,
bmpSource.PixelHeight,
bmpSource.DpiX, bmpSource.DpiY,
bmpSource.Format, null);
imageWriteableBitmap.WritePixels(
new Int32Rect(0, 0, bmpSource.PixelWidth, bmpSource.PixelHeight), pixelData, stride, 0);
paintImageCanvas.Source = imageWriteableBitmap;
}
}

Control not properly positioning programmatically

So im trying to place an Ellipse (named Dot) on a random location inside a grid.
But it only spawns on 1/4th (lower right) of the grid instead of the complete grid.
Example: When i put the margin of the Dot to Dot.Margin = new Thickness(0, 0, 0, 0); the Dot will spawn in the center of the screen. When i change it to Dot.Margin = new Thickness(200, 0, 0, 0); it will have a very small offset to the right but not even close to 200 pixels.
Outcome after creating alot of circles without removing them:
http://i.imgur.com/3XCMYyC.png
The red rectangle is the spawn area.
C#
//Gives Dot a position
public void placeDot()
{
//Give Dot random position
// The farthest left the dot can be
double minLeft = 0;
// The farthest right the dot can be without it going off the screen
double maxLeft = spawnArea.ActualWidth - Dot.Width;
// The farthest up the dot can be
double minTop = 0;
// The farthest down the dot can be without it going off the screen
double maxTop = spawnArea.ActualHeight - Dot.Height;
double left = RandomBetween(minLeft, maxLeft);
double top = RandomBetween(minTop, maxTop);
Dot.Margin = new Thickness(left, top, 0, 0);
}
//createEllipse method, used for creating new Dots
public void createEllipse()
{
spawnArea.Children.Remove(Dot);
//Create new Dot
DotImg.ImageSource =
new BitmapImage(new Uri(#"Images/hitcircle.png", UriKind.Relative));
Dot = new Ellipse() { Width = hitcircleSettingPath, Height = hitcircleSettingPath, Fill = DotImg, };
//Activates placeDot() method to give the Dot a random location
placeDot();
//Add Dot to the game area
spawnArea.Children.Add(Dot);
}
XAML This is the complete XAML i think there might be something wrong with the XAML but below is a shorter snippet where it does work how i want it but without the other stuff.
<Window x:Name="Grid" x:Class="ReactieSnelheid_Game.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:ReactieSnelheid_Game"
mc:Ignorable="d"
Title="Dot Program" Height="768" Width="1366" WindowStartupLocation="CenterScreen" Cursor="Pen" Icon="Images/icon.ico" ResizeMode="NoResize" WindowState="Maximized" WindowStyle="None" Background="Black" HorizontalContentAlignment="Center" VerticalContentAlignment="Center" Foreground="{x:Null}" KeyDown="Grid_KeyDown">
<Grid x:Name="backgroundImageGrid" Margin="0,0,0,0" MouseDown="LayoutRoot_MouseDown">
<Grid.Background>
<ImageBrush x:Name="backgroundBrush" ImageSource="Images/background.png" Opacity="0.25"/>
</Grid.Background>
<Grid x:Name="gameWrapper">
<Grid.Background>
<SolidColorBrush Color="Black" Opacity="0.25"/>
</Grid.Background>
<Label x:Name="reactionTime" Content="1000ms" HorizontalAlignment="Left" Margin="10,10,0,0" VerticalAlignment="Top" FontSize="40" FontFamily="PMingLiU-ExtB" Foreground="White"/>
<Label x:Name="circleSize" Content="150x150" HorizontalAlignment="Left" Margin="10,73,0,0" VerticalAlignment="Top" FontSize="26.667" FontFamily="PMingLiU-ExtB" Foreground="White" Background="{x:Null}"/>
<Label x:Name="dotCount" Content="000000" HorizontalAlignment="Left" Margin="28,0,0,-1" Foreground="White" FontSize="80" RenderTransformOrigin="0.5,0.5" FontFamily="PMingLiU-ExtB" VerticalAlignment="Bottom" Background="{x:Null}">
<Label.RenderTransform>
<TransformGroup>
<ScaleTransform/>
<SkewTransform AngleX="-11.056"/>
<RotateTransform/>
<TranslateTransform X="-8.305"/>
</TransformGroup>
</Label.RenderTransform>
</Label>
<Label x:Name="scoreCount" Content="9999999999999999" Margin="0,0,10,10" Foreground="White" FontSize="80" FontFamily="PMingLiU-ExtB" HorizontalAlignment="Right" Height="106" VerticalAlignment="Bottom"/>
<Rectangle x:Name="startTimerBtn" RenderTransformOrigin="0.39,-0.75" Margin="144,10,0,0" Width="128" Height="64" HorizontalAlignment="Left" VerticalAlignment="Top" MouseDown="startTimerBtn_MouseDown">
<Rectangle.Fill>
<ImageBrush ImageSource="Images/starttimer.png"/>
</Rectangle.Fill>
</Rectangle>
<Grid x:Name="spawnArea" Margin="0,115,0,121" Background="Red"/>
</Grid>
<Grid x:Name="pauseScreen">
<Grid.Background>
<SolidColorBrush Color="#FF81D650" Opacity="0.25"/>
</Grid.Background>
<Grid x:Name="pauseScreenBtns" Margin="389,153,389,152" HorizontalAlignment="Center" VerticalAlignment="Center">
<Rectangle x:Name="Startbtn" Height="332" Width="332" MouseDown="Startbtn_MouseDown" HorizontalAlignment="Center" VerticalAlignment="Bottom" Margin="129,0,127,76">
<Rectangle.Fill>
<ImageBrush ImageSource="Images/Start.png"/>
</Rectangle.Fill>
</Rectangle>
<Rectangle x:Name="settingsBtn" MouseDown="settingsBtn_MouseDown" Margin="-5,189,0,0" HorizontalAlignment="Left" VerticalAlignment="Top" Width="129" Height="63">
<Rectangle.Fill>
<ImageBrush ImageSource="Images/settings.png"/>
</Rectangle.Fill>
</Rectangle>
<Rectangle x:Name="resetBtn" MouseDown="resetBtn_MouseDown" Margin="0,190,-6,0" Width="128" Height="62" HorizontalAlignment="Right" VerticalAlignment="Top">
<Rectangle.Fill>
<ImageBrush ImageSource="Images/reset.png"/>
</Rectangle.Fill>
</Rectangle>
<Rectangle x:Name="quitBtn" RenderTransformOrigin="0.39,-0.75" Margin="232,399,0,0" Width="129" Height="64" HorizontalAlignment="Left" VerticalAlignment="Top" MouseDown="quitBtn_MouseDown">
<Rectangle.Fill>
<ImageBrush ImageSource="Images/quit.png"/>
</Rectangle.Fill>
</Rectangle>
</Grid>
</Grid>
</Grid>
</Window>
Shorter XAML
<Window x:Class="TESTPROJECTEN.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:TESTPROJECTEN"
mc:Ignorable="d"
Title="MainWindow" Height="768" Width="1366">
<Grid x:Name="gameWrapper">
<Grid x:Name="spawnArea"/>
</Grid>
</Window>

Ellipse has Alignment = Stretch by default. But you set a fixed Width and Height so it looks like ellipse is centered. Try set location relative to top left corner
Dot = new Ellipse() { Width = hitcircleSettingPath, Height = hitcircleSettingPath, Fill = DotImg, };
Dot.HorizontalAlignment = HorizontalAlignment.Left;
Dot.VerticalAlignment = VerticalAlignment.Top;

it will have a very small offset to the right but not even close to
200 pixels.
First of all, as far as I remember, WPF doesn't use those numbers as pixels, but as some internal values. I can't remember the name of those units, but bottom line, they are not pixels.
Now for your actual problem:
Wpf grid places all his child controls by default in the center, so when you are putting the ellipse inside the grid and set a margin 200, it sets the margin from the center.
With that in mind, you can change your random algorithm to make the bubbles appear all over the grid:
//Gives Dot a position
public void placeDot()
{
//Give Dot random position
double halfSide = (spawnArea.ActualWidth - Dot.Width) / 2;
// The farthest left the dot can be
double minLeft = -(halfSide - (Dot.ActualWidth / 2));
// The farthest right the dot can be without it going off the screen
double maxLeft = halfSide - (Dot.ActualWidth / 2);
// The farthest up the dot can be
double minTop = -(halfSide - (Dot.ActualHeight / 2));
// The farthest down the dot can be without it going off the screen
double maxTop = halfSide - (Dot.ActualHeight / 2);
double left = RandomBetween(minLeft, maxLeft);
double top = RandomBetween(minTop, maxTop);
Dot.Margin = new Thickness(left, top, 0, 0);
}
I hope I didn't miss anything. I didn't run this code, so it might need adjustments, but this is the main line to follow.
Happy Coding! :)

Double tap to zoom Windows Phone

I've a little problem with double tap to zoom, when I tap twice the image enlarge but I can see only half image and I can't move image to see other half of image. How can I for see all image?
The code is:
[XAML]
<!--LayoutRoot è la griglia radice in cui viene inserito tutto il contenuto della pagina-->
<Grid x:Name="LayoutRoot" Background="#FF0A5BC4">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<!--ContentPanel - inserire ulteriore contenuto qui-->
<Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
<StackPanel Margin="-12,10,-11,98" HorizontalAlignment="Center" VerticalAlignment="Center">
<Image x:Name="immagine_Name" Margin="1,1,1,1" Stretch="UniformToFill">
<toolkit:GestureService.GestureListener>
<toolkit:GestureListener PinchStarted="GestureListener_PinchStarted"
PinchDelta="GestureListener_PinchDelta"
DoubleTap="GestureListener_DoubleTap"/>
</toolkit:GestureService.GestureListener>
<Image.RenderTransform>
<CompositeTransform x:Name="transform" ScaleX="1" ScaleY="1" TranslateX="0" TranslateY="0"/>
</Image.RenderTransform>
</Image>
</StackPanel>
<StackPanel Background="#FF094AB2" Margin="-12,675,-11,0">
</StackPanel>
</Grid>
</Grid>
[C#]
private void GestureListener_DoubleTap(object sender, GestureEventArgs e)
{
if (transform.ScaleX == 1 && transform.ScaleY == 1) //The scale is currently 1, enlarge
{
transform.ScaleX = 1.5;
transform.ScaleY = 1.5;
}
else
{ //Its bigger, reset to 1.
transform.ScaleX = 1;
transform.ScaleY = 1;
}
}
This is the image to normal size:
http://i.imgur.com/vlUlbes.jpg
And this is the image after double tap, that I can't move for see the rest of image:
http://i.imgur.com/AZwsccq.jpg
Thank you for all who help me.

Fill Ellipse based on percentage

I have created Ellipse in XAML.
Here is the code :
<Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
<Ellipse Width="400" Stroke="DodgerBlue" Height="400" StrokeThickness="75" Fill="Transparent">
</Ellipse>
</Grid>
Say the Ellipse is 100% if its 20% the blue color should fill only till that and also display the percentage text in the center (empty area) of ellipse.
EDIT
I have add text to display in center.
<Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
<Ellipse Width="400" Stroke="DodgerBlue" Height="400" StrokeThickness="75" Fill="Transparent">
</Ellipse>
<TextBlock VerticalAlignment="Center"
HorizontalAlignment="Center"
Text="20"
FontSize="125"/>
</Grid>
EDIT 2
Here is what how it looks like i am trying to acheive:
here the orange color with the 20% fill.

You can use an arc control preset in the assembly Microsoft.Expression.Drawing
It has properties like StartAngle and EndAngle which could be well manipulated accordingly.
<es:Arc x:Name="arc" ArcThickness="3" ArcThicknessUnit="Pixel" EndAngle="360" Fill="Black" Height="270" Canvas.Left="101.94" Stroke="Black" StartAngle="0" UseLayoutRounding="False" Width="269.941" Canvas.Top="12" />
Now what you could do using this control is : Just take two similar arcs One superimposing the other,
color the below one(1st arc) with Blue and give start and end angle properties to the red color arc(2nd arc) which would make your layout look like the way it is mentioned in design two.
Raw Usage:
<Canvas x:Name="canvas1" Margin="0,10,0,0" Height="300" Width="480" HorizontalAlignment="Center">
<es:Arc x:Name="arc" ArcThickness="3" ArcThicknessUnit="Pixel" Fill="Black" Height="100" Canvas.Left="0" Stroke="Blue" UseLayoutRounding="False" Width="100" Canvas.Top="0"/>
</Canvas>
<es:Arc x:Name="arc" ArcThickness="3" EndAngle="120" StartAngle="0" ArcThicknessUnit="Pixel" Fill="Blue" Height="100" Canvas.Left="0" Stroke="Blue" UseLayoutRounding="False" Width="100" Canvas.Top="0"/>
</Canvas>
Check this link as well

User control version would consist of two parts: XAML + code-behind.
XAML part:
<UserControl
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:Project.CustomControls"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:Interactivity="using:Microsoft.Xaml.Interactivity" xmlns:Core="using:Microsoft.Xaml.Interactions.Core"
mc:Ignorable="d"
d:DesignHeight="40"
d:DesignWidth="40">
<Grid Width="40" Height="40">
<Ellipse StrokeThickness="3" Stroke="#FF89CE25"/>
<Path Stroke="Red" StrokeThickness="2" x:Name="arcPath">
<Path.Data>
<PathGeometry>
<PathFigure StartPoint="20,1">
<ArcSegment x:Name="myArc" SweepDirection="Clockwise" IsLargeArc="True" Point="20,1"/>
</PathFigure>
</PathGeometry>
</Path.Data>
</Path>
</Grid>
Code-behind file (short version, no fluff):
public sealed partial class MyCustomControl : UserControl
{
public double ProgressValue
{
get { return (double)GetValue(ProgressValueProperty); }
set { SetValue(ProgressValueProperty, value); }
}
// Using a DependencyProperty as the backing store for ProgressValue. This enables animation, styling, binding, etc...
public static readonly DependencyProperty ProgressValueProperty =
DependencyProperty.Register("ProgressValue", typeof(double), typeof(MyCustomControl), new PropertyMetadata(0.0, OnProgressValueChanged));
private static void OnProgressValueChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
//throw new NotImplementedException();
MyCustomControl circularProgressBar = d as MyCustomControl;
if (circularProgressBar != null)
{
double r = 19;
double x0 = 20;
double y0 = 20;
circularProgressBar.myArc.Size = new Size(19, 19);
double angle = 90 - (double)e.NewValue / 100 * 360;
double radAngle = angle * (PI / 180);
double x = x0 + r * Cos(radAngle);
double y = y0 - r * Sin(radAngle);
if (circularProgressBar.myArc != null)
{
circularProgressBar.myArc.IsLargeArc = ((double)e.NewValue >= 50);
circularProgressBar.myArc.Point = new Point(x, y);
}
}
}
public MyCustomControl()
{
this.InitializeComponent();
}
}
Now, you can throw your CustomControl into any place in your XAML and bind the ProgressValue property to the respective data source. The arc would redraw itself and will fill the Ellipse shape proportionally to the value (a value from 0-100).

How to find UserControl width in WPF?

<UserControl x:Class="JIMS.View.Settings.Settings"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Name="SettingsWindow">
<Border Style="{StaticResource WindowBorderStyle}" Height="100">
<StackPanel Orientation="Vertical">
<my:TitleBar Title="settings"/>
<StackPanel Orientation="Horizontal">
<StackPanel Orientation="Horizontal">
<StackPanel Orientation="Vertical" Margin="10,0,0,0">
<Label>Theme :</Label>
</StackPanel>
<StackPanel Orientation="Vertical" Width="200" Margin="0,0,10,0">
<ComboBox Name="cmbTheme" ItemsSource="{Binding Path=Themes}" ></ComboBox>
</StackPanel>
</StackPanel>
</StackPanel>
</StackPanel>
</Border>
</UserControl>
This is my UserControl and i have not set its Width and Height properties.
But in some codebehind i want to get the Height and width of this UserControl and i am not able to get them.
double width=uctrl.Width;
It gives me NaN while
double width=ctrl.ActualWidth;
giving me 0
The code where i need width and height
private void OpenChild(UserControl ctrl)
{
bool alreadyExist = false;
ctrl.Uid = ctrl.Name;
foreach (UIElement child in JIMSCanvas.Children)
{
if (child.Uid == ctrl.Uid)
{
alreadyExist = true;
Canvas.SetZIndex(child, GetMaxZIndex);
}
}
if (!alreadyExist)
{
JIMSCanvas.Children.Add(ctrl);
JIMSCanvas.InvalidateMeasure();
double top = (JIMSCanvas.ActualHeight - ctrl.Height) / 2;
double left = (JIMSCanvas.ActualWidth - ctrl.Width) / 2;
Canvas.SetLeft(ctrl, left);
Canvas.SetTop(ctrl, top);
}
}

In a brand new project I wrote this (and it gave me updated width when changing the Window):
<Window xmlns:my="clr-namespace:WpfApplication2"
x:Class="WpfApplication2.Window32"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Window32"
Height="300"
Width="300">
<Grid>
<my:UserControl3 x:Name="uc3" />
<TextBlock Height="23"
HorizontalAlignment="Left"
Margin="126,121,0,0"
Name="textBlock1"
Text="{Binding ElementName=uc3, Path=ActualWidth}"
VerticalAlignment="Top" />
</Grid>
</Window>

I solved the Issue with this code...
private void OpenChild(UserControl ctrl)
{
bool alreadyExist = false;
ctrl.Uid = ctrl.Name;
foreach (UIElement child in JIMSCanvas.Children)
{
if (child.Uid == ctrl.Uid)
{
alreadyExist = true;
Canvas.SetZIndex(child, GetMaxZIndex);
}
}
if (!alreadyExist)
{
JIMSCanvas.Children.Add(ctrl);
JIMSCanvas.UpdateLayout();
double top = (JIMSCanvas.ActualHeight - ctrl.ActualHeight) / 2;
double left = (JIMSCanvas.ActualWidth - ctrl.ActualWidth) / 2;
Canvas.SetLeft(ctrl, left);
Canvas.SetTop(ctrl, top);
}
}
I have used JIMSCanvas.UpdateLayout();
Thank all for helping and especially #NestorArturo