Issue With Xamarin.Forms Images in iOS Renderer - xamarin

I hope someone can help me with this weird problem.
I'm in Xamarin Forms, in a renderer. I'm passing a Xamarin.Forms.ImageSource into a ImageLoaderSourceHandler.
var_imageLoader = new ImageLoaderSourceHandler();
However, when I await the LoadImageAsync method it always returns null, rather than UIimage.
if (_view.Icon?.Source != null)
{
_iconImageView.Image =
await _imageLoader.LoadImageAsync(_view.Icon.Source);
}
My images are in the Resource directory and are BundleResourceas build action.
The file naming is correct (menu.png, menu#2x.png, menu#3x.png) and I've run out if ideas.
Anyone got a clue or two ?
Thanks

ImageLoaderSourceHandler is used if you want to download images from a Url.
Since your files are local you need to use FileImageSourceHandler
You can use this help method to get you the right type.
private static IImageSourceHandler GetHandler(ImageSource source)
{
IImageSourceHandler returnValue = null;
if (source is UriImageSource)
{
returnValue = new ImageLoaderSourceHandler();
}
else if (source is FileImageSource)
{
returnValue = new FileImageSourceHandler();
}
else if (source is StreamImageSource)
{
returnValue = new StreamImagesourceHandler();
}
return returnValue;
}

Related

Xamarin: CGImageSource.FromUrl returning null

I am using the following code in my application.
string imageUrl = "https://imageUrl.png/"; //This is a valid url. I can see the image when I paste the url into my web browser
var url = new NSUrl(imageUrl);
using (CGImageSource source = CGImageSource.FromUrl(url))
{
if (source != null)
{
//I never get here
}
}
Why is source always null? I've tried many different imageUrls, all with the same result.
Your photo address seems to be HTTPS prefix.which is different from HTTP.You can try another URL be HTTP prefix.If the address must be HTTPS,I suggest you use some SDK.
or you can use the following code,they works when use http
string str = ""; //your image url
NSData ImageData = NSData.FromUrl(new NSUrl(str) );
UIImage image = new UIImage(ImageData);
if (image != null)
{
Console.Write("success");
}
else
{
Console.Write("fail");
}

How to get IEditorOperations from IVsTextView?

I'm developing my first Visual Studio (2015 Community) Command Menu and I'm trying to get access to IEditorOperations to delete text, send backspace etc. but I'm not sure how to. I can do:
var Service = Provider.GetService(typeof(IEditorOperationsFactoryService)) as IEditorOperationsFactoryService;
Service.GetEditorOperations(???);
I'm not sure what to pass in the ??? since I don't have access to an ITextView instead what I have is a IVsTExtView via:
IVsTextView View;
IVsTextManager Manager = (IVsTextManager)ServiceProvider.GetService(typeof(SVsTextManager));
int MustHaveFocus = 1;
Manager.GetActiveView(MustHaveFocus, null, out View);
When creating the Command Menu, VS generates a template for me with a private ctor creating the command service, binding it to the command set id etc. An overridden Initialize method, and a bunch of properties.
Any ideas?
EDIT: After help from Sergey, I managed to get a bit further. But now I get a null when I try to get the IEditorOperationsFactoryService, all the other values are valid.
static IEditorOperations GetEditorService(IServiceProvider Provider, IVsTextView VsView)
{
IEditorOperations Result;
try
{
var Model = (IComponentModel)Provider.GetService(typeof(SComponentModel));
var Editor = (IEditorOperationsFactoryService)Provider.GetService(typeof(IEditorOperationsFactoryService)); // returns null
var Adaptor = Model.GetService<IVsEditorAdaptersFactoryService>();
IWpfTextView TextView = Adaptor.GetWpfTextView(VsView);
Result = Editor.GetEditorOperations(TextView);
}
catch (Exception e)
{
System.Windows.Forms.MessageBox.Show(e.ToString());
Result = null;
}
return (Result);
}
You can get IEditorOperationsFactoryService instance from variable named Model, like this:
var Model = (IComponentModel)this.ServiceProvider.GetService(typeof(SComponentModel));
var Editor = (IEditorOperationsFactoryService)Model.GetService<IEditorOperationsFactoryService>();
You can get IWpfTextView (that implements ITextView) from IVsTextView using:
IVsTextView textView = ...;
IWpfTextView v = GetEditorAdaptersFactoryService().GetWpfTextView(textView);
private Microsoft.VisualStudio.Editor.IVsEditorAdaptersFactoryService GetEditorAdaptersFactoryService()
{
Microsoft.VisualStudio.ComponentModelHost.IComponentModel componentModel =
(Microsoft.VisualStudio.ComponentModelHost.IComponentModel)serviceProvider.GetService(
typeof(Microsoft.VisualStudio.ComponentModelHost.SComponentModel));
return componentModel.GetService<Microsoft.VisualStudio.Editor.IVsEditorAdaptersFactoryService>();
}

Silverlight app freezes on Mac when file saved

Pretty simple code to launch SaveFileDialog and then save data.
Opens prompt, I can select where I save, it saves file and then whole tab/app freezes. Obviously works fine on Windows/IE. Any suggestions?
private void SavePDFFile()
{
var saveFileDialog = new SaveFileDialog
{
DefaultExt = "pdf",
Filter = string.Format("Document(.{0})|*.{0}", "pdf"),
FilterIndex = 1,
DefaultFileName = DateTime.Now.ToString("HHmmMMddyyyy")
};
var saveClicked = saveFileDialog.ShowDialog();
if (!saveClicked.HasValue || !saveClicked.Value) return;
var fileStream = saveFileDialog.OpenFile();
try
{
this.IsBusy = true;
fileStream.Write(this.PDFData, 0, this.PDFData.Length);
fileStream.Close();
}
catch (Exception ex)
{
this.DisplayErrorMessage("Error saving PDF file", ex);
}
finally
{
this.IsBusy = false;
}
}
Answering my own question. This is nothing to do with code itself. It is security issue. In order to allow this code to execute on Mac (and it seems new versions of IE as well) you need to give it more permissions.
On IE you need to add website to list of Trusted sites.
On Mac - you need to set Silverlight to run in "Unsafe" mode. This is in Preferences/Security/Silverlight and need to select website, hold "Option" key and then open dropdown to see that option. Took a while to find it..
#katit I also faced this issue while working on a Silverlight OOB application.. my app was working fine in Windows but in Mac it got freezed and I have to force quit to use it again.
I was actually reading a PDF (stored in field type - 'varbinary') from server and storing it to user's local machine.
The solution worked for me is to download file chunks in parts (I used buffer size - 1 MB).
Not sure what file size you are using when your application gets freeze.. but I think, writing 'PDFData' to filestream in small parts may help you.
Also, add filestream.Flush(); (see highlighted in below code) in your code and see if this helps:
private void SavePDFFile()
{
var saveFileDialog = new SaveFileDialog
{
DefaultExt = "pdf",
Filter = string.Format("Document(.{0})|*.{0}", "pdf"),
FilterIndex = 1,
DefaultFileName = DateTime.Now.ToString("HHmmMMddyyyy")
};
var saveClicked = saveFileDialog.ShowDialog();
if (!saveClicked.HasValue || !saveClicked.Value) return;
var fileStream = saveFileDialog.OpenFile();
try
{
this.IsBusy = true;
fileStream.Write(this.PDFData, 0, this.PDFData.Length);
**filestream.Flush();**
fileStream.Close();
}
catch (Exception ex)
{
this.DisplayErrorMessage("Error saving PDF file", ex);
}
finally
{
this.IsBusy = false;
}
}

Binding Image stored in the Isolated Storage to Image Control in Windows Phone

Is it possible to bind the image present in the Isolates storage to image control through xaml. I found some implementations like getting the image through the property and binding that into xaml control. But this is not the implementation what I am searching for. My question is like, writing an attach property and helper method to fetch the content from Isolated storage. I found a similar implementation in LowProfileImage class, used in windows phone 7. But I think it is deprecated now. If anyone tried similar implementations please help me to achieve the same. Also if implementation have any performance drains please mention that info too.
Yes, it is possible to use images from isolated storage in the app UI. It requires loading the image from the file into the BitmapImage and then binding ImageSource of your control to that BitmapImage. I'm using the following approach:
First, there's a method to load image asynchronously:
private Task<Stream> LoadImageAsync(string filename)
{
return Task.Factory.StartNew<Stream>(() =>
{
if (filename == null)
{
throw new ArgumentException("one of parameters is null");
}
Stream stream = null;
using (var isoStore = IsolatedStorageFile.GetUserStoreForApplication())
{
if (isoStore.FileExists(filename))
{
stream = isoStore.OpenFile(filename, System.IO.FileMode.Open, FileAccess.Read);
}
}
return stream;
});
}
Then it can be used like this:
public async Task<BitmapSource> FetchImage()
{
BitmapImage image = null;
using (var imageStream = await LoadImageAsync(doc.ImagePath))
{
if (imageStream != null)
{
image = new BitmapImage();
image.SetSource(imageStream);
}
}
return image;
}
And finally you just assign return value of FetchImage() method to some of your view model's property, to which the UI element is bound. Of course, your view model should properly implement INotifyPropertyChanged interface for this approach to work reliably.
If you want to use attached properties approach, here's how you do it:
public class IsoStoreImageSource : DependencyObject
{
public static void SetIsoStoreFileName(UIElement element, string value)
{
element.SetValue(IsoStoreFileNameProperty, value);
}
public static string GetIsoStoreFileName(UIElement element)
{
return (string)element.GetValue(IsoStoreFileNameProperty);
}
// Using a DependencyProperty as the backing store for IsoStoreFileName. This enables animation, styling, binding, etc...
public static readonly DependencyProperty IsoStoreFileNameProperty =
DependencyProperty.RegisterAttached("IsoStoreFileName", typeof(string), typeof(IsoStoreImageSource), new PropertyMetadata("", Changed));
private static void Changed(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
Image img = d as Image;
if (img != null)
{
var path = e.NewValue as string;
SynchronizationContext uiThread = SynchronizationContext.Current;
Task.Factory.StartNew(() =>
{
using (var isoStore = IsolatedStorageFile.GetUserStoreForApplication())
{
if (isoStore.FileExists(path))
{
var stream = isoStore.OpenFile(path, System.IO.FileMode.Open, FileAccess.Read);
uiThread.Post(_ =>
{
var _img = new BitmapImage();
_img.SetSource(stream);
img.Source = _img;
}, null);
}
}
});
}
}
}
And then in XAML:
<Image local:IsoStoreImageSource.IsoStoreFileName="{Binding Path}" />
Some limitations of this approach:
It only works on Image control, though you can change this to a whichever type you want. It's just not very generic.
Performance-wise, it will use a thread from the threadpool every time image source is changed. It's the only way to do asynchronous read from isolated storage on Windows Phone 8 right now. And you definitely don't want to do this synchronously.
But it has one one important advantage:
It works! :)
I like the above approach but there is a simpler more hacky way of doing it if you are interested.
You can go into your xaml and bind the image source to an string property then put the file path into the property dynamically.
<!-- XAML CODE -->
<Image Source="{Binding imagePath}"/>
//Behind property
public String imagePath { get; set; }
load your path into the image path then bind the image source to the image path string. You might have to do an INotifyPropertyChanged but this method should work with proper binding.

How to tell if .NET code is being run by Visual Studio designer

I am getting some errors thrown in my code when I open a Windows Forms form in Visual Studio's designer. I would like to branch in my code and perform a different initialization if the form is being opened by designer than if it is being run for real.
How can I determine at run-time if the code is being executed as part of designer opening the form?
if (System.ComponentModel.LicenseManager.UsageMode == System.ComponentModel.LicenseUsageMode.Designtime)
{
// Design time logic
}
To find out if you're in "design mode":
Windows Forms components (and controls) have a DesignMode property.
Windows Presentation Foundation controls should use the IsInDesignMode attached property.
The Control.DesignMode property is probably what you're looking for. It tells you if the control's parent is open in the designer.
In most cases it works great, but there are instances where it doesn't work as expected. First, it doesn't work in the controls constructor. Second, DesignMode is false for "grandchild" controls. For example, DesignMode on controls hosted in a UserControl will return false when the UserControl is hosted in a parent.
There is a pretty easy workaround. It goes something like this:
public bool HostedDesignMode
{
get
{
Control parent = Parent;
while (parent!=null)
{
if(parent.DesignMode) return true;
parent = parent.Parent;
}
return DesignMode;
}
}
I haven't tested that code, but it should work.
The most reliable approach is:
public bool isInDesignMode
{
get
{
System.Diagnostics.Process process = System.Diagnostics.Process.GetCurrentProcess();
bool res = process.ProcessName == "devenv";
process.Dispose();
return res;
}
}
The most reliable way to do this is to ignore the DesignMode property and use your own flag that gets set on application startup.
Class:
public static class Foo
{
public static bool IsApplicationRunning { get; set; }
}
Program.cs:
[STAThread]
static void Main()
{
Foo.IsApplicationRunning = true;
// ... code goes here ...
}
Then just check the flag whever you need it.
if(Foo.IsApplicationRunning)
{
// Do runtime stuff
}
else
{
// Do design time stuff
}
I had the same problem in Visual Studio Express 2013. I tried many of the solutions suggested here but the one that worked for me was an answer to a different thread, which I will repeat here in case the link is ever broken:
protected static bool IsInDesigner
{
get { return (Assembly.GetEntryAssembly() == null); }
}
The devenv approach stopped working in VS2012 as the designer now has its own process. Here is the solution I am currently using (the 'devenv' part is left there for legacy, but without VS2010 I am not able to test that though).
private static readonly string[] _designerProcessNames = new[] { "xdesproc", "devenv" };
private static bool? _runningFromVisualStudioDesigner = null;
public static bool RunningFromVisualStudioDesigner
{
get
{
if (!_runningFromVisualStudioDesigner.HasValue)
{
using (System.Diagnostics.Process currentProcess = System.Diagnostics.Process.GetCurrentProcess())
{
_runningFromVisualStudioDesigner = _designerProcessNames.Contains(currentProcess.ProcessName.ToLower().Trim());
}
}
return _runningFromVisualStudioDesigner.Value;
}
}
/// <summary>
/// Are we in design mode?
/// </summary>
/// <returns>True if in design mode</returns>
private bool IsDesignMode() {
// Ugly hack, but it works in every version
return 0 == String.CompareOrdinal(
"devenv.exe", 0,
Application.ExecutablePath, Application.ExecutablePath.Length - 10, 10);
}
System.Diagnostics.Debugger.IsAttached
It's hack-ish, but if you're using VB.NET and when you're running from within Visual Studio My.Application.Deployment.CurrentDeployment will be Nothing, because you haven't deployed it yet. I'm not sure how to check the equivalent value in C#.
using (System.Diagnostics.Process process = System.Diagnostics.Process.GetCurrentProcess())
{
bool inDesigner = process.ProcessName.ToLower().Trim() == "devenv";
return inDesigner;
}
I tried the above code (added a using statement) and this would fail on some occasions for me. Testing in the constructor of a usercontrol placed directly in a form with the designer loading at startup. But would work in other places.
What worked for me, in all locations is:
private bool isDesignMode()
{
bool bProcCheck = false;
using (System.Diagnostics.Process process = System.Diagnostics.Process.GetCurrentProcess())
{
bProcCheck = process.ProcessName.ToLower().Trim() == "devenv";
}
bool bModeCheck = (System.ComponentModel.LicenseManager.UsageMode == System.ComponentModel.LicenseUsageMode.Designtime);
return bProcCheck || DesignMode || bModeCheck;
}
Maybe a bit overkill, but it works, so is good enough for me.
The success in the example noted above is the bModeCheck, so probably the DesignMode is surplus.
You check the DesignMode property of your control:
if (!DesignMode)
{
//Do production runtime stuff
}
Note that this won't work in your constructor because the components haven't been initialized yet.
When running a project, its name is appended with ".vshost".
So, I use this:
public bool IsInDesignMode
{
get
{
Process p = Process.GetCurrentProcess();
bool result = false;
if (p.ProcessName.ToLower().Trim().IndexOf("vshost") != -1)
result = true;
p.Dispose();
return result;
}
}
It works for me.
I'm not sure if running in debug mode counts as real, but an easy way is to include an if statement in your code that checkes for System.Diagnostics.Debugger.IsAttached.
If you created a property that you don't need at all at design time, you can use the DesignerSerializationVisibility attribute and set it to Hidden. For example:
protected virtual DataGridView GetGrid()
{
throw new NotImplementedException("frmBase.GetGrid()");
}
[DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
public int ColumnCount { get { return GetGrid().Columns.Count; } set { /*Some code*/ } }
It stopped my Visual Studio crashing every time I made a change to the form with NotImplementedException() and tried to save. Instead, Visual Studio knows that I don't want to serialize this property, so it can skip it. It only displays some weird string in the properties box of the form, but it seems to be safe to ignore.
Please note that this change does not take effect until you rebuild.
We use the following code in UserControls and it does the work. Using only DesignMode will not work in your app that uses your custom user controls as pointed out by other members.
public bool IsDesignerHosted
{
get { return IsControlDesignerHosted(this); }
}
public bool IsControlDesignerHosted(System.Windows.Forms.Control ctrl)
{
if (ctrl != null)
{
if (ctrl.Site != null)
{
if (ctrl.Site.DesignMode == true)
return true;
else
{
if (IsControlDesignerHosted(ctrl.Parent))
return true;
else
return false;
}
}
else
{
if (IsControlDesignerHosted(ctrl.Parent))
return true;
else
return false;
}
}
else
return false;
}
Basically the logic above boils down to:
public bool IsControlDesignerHosted(System.Windows.Forms.Control ctrl)
{
if (ctrl == null) return false;
if (ctrl.Site != null && ctrl.Site.DesignMode) return true;
return IsControlDesignerHosted(ctrl.Parent);
}
If you are in a form or control you can use the DesignMode property:
if (DesignMode)
{
DesignMode Only stuff
}
I found the DesignMode property to be buggy, at least in previous versions of Visual Studio. Hence, I made my own using the following logic:
Process.GetCurrentProcess().ProcessName.ToLower().Trim() == "devenv";
Kind of a hack, I know, but it works well.
System.ComponentModel.Component.DesignMode == true
To solve the problem, you can also code as below:
private bool IsUnderDevelopment
{
get
{
System.Diagnostics.Process process = System.Diagnostics.Process.GetCurrentProcess();
if (process.ProcessName.EndsWith(".vshost")) return true;
else return false;
}
}
Here's another one:
//Caters only to thing done while only in design mode
if (App.Current.MainWindow == null){ // in design mode }
//Avoids design mode problems
if (App.Current.MainWindow != null) { //applicaiton is running }
After testing most of the answers here, unfortunately nothing worked for me (VS2015).
So I added a little twist to JohnV's answer, which didn't work out of the box, since DesignMode is a protected Property in the Control class.
First I made an extension method which returns the DesignMode's Property value via Reflection:
public static Boolean GetDesignMode(this Control control)
{
BindingFlags bindFlags = BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Static;
PropertyInfo prop = control.GetType().GetProperty("DesignMode", bindFlags);
return (Boolean)prop.GetValue(control, null);
}
and then I made a function like JohnV:
public bool HostedDesignMode
{
get
{
Control parent = Parent;
while (parent != null)
{
if (parent.GetDesignMode()) return true;
parent = parent.Parent;
}
return DesignMode;
}
}
This is the only method that worked for me, avoiding all the ProcessName mess, and while reflection should not be used lightly, in this case it did all the difference! ;)
EDIT:
You can also make the second function an extension method like this:
public static Boolean IsInDesignMode(this Control control)
{
Control parent = control.Parent;
while (parent != null)
{
if (parent.GetDesignMode())
{
return true;
}
parent = parent.Parent;
}
return control.GetDesignMode();
}
For WPF (hopefully this is useful for those WPF people stumbling upon this question):
if (System.ComponentModel.DesignerProperties.GetIsInDesignMode(new DependencyObject()))
{
}
GetIsInDesignMode requires a DependencyObject. If you don't have one, just create one.
/// <summary>
/// Whether or not we are being run from the Visual Studio IDE
/// </summary>
public bool InIDE
{
get
{
return Process.GetCurrentProcess().ProcessName.ToLower().Trim().EndsWith("vshost");
}
}
Here's a flexible way that is adaptable to where you compile from as well as whether or not you care which mode you're in.
string testString1 = "\\bin\\";
//string testString = "\\bin\\Debug\\";
//string testString = "\\bin\\Release\\";
if (AppDomain.CurrentDomain.BaseDirectory.Contains(testString))
{
//Your code here
}

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