Develop Reference

App crashes when I navigate to another frame

When I click, the second page is loaded, but the application crashes with System.NullReferenceException:
private async void Forecast_Click(object sender, RoutedEventArgs e)
{
await
CoreApplication.MainView.CoreWindow.Dispatcher.RunAsync(
CoreDispatcherPriority.Normal,
() => {
Frame.Navigate(typeof(Forecast), null);
}
);
}

A NullReferenceException occurs when trying to access a member of an object which is null.
This is likely happening within your code. Reproduce the error while running your application in Debug mode, and view the call stack/current point of execution when you encounter the exception. It should then be clear to you in which statement your code is trying to access a member of a null object.

InvalidOperationException on Application.Exit

Can someone tell me why the exitToolStripMenuItem_Click throws an InvalidOperationException. I know it happens due to plugin.Close() being called. However, I do not understand why. Closing the Form1 via the "X" button does not trigger the exception. Calling Application.Exit() does though. Below is a sample to demonstrate what is happening in my main app. In my main app events are triggered off certain forms closing so I need to make sure I call Close on each forms. I could change Application.Exit() to a Close() however after reading MSDN I don't feel like this is the correct solution. Any ideas would be helpful, thanks.
Note: The main application I'm working on is multi-threaded.
public partial class Form1 : Form
{
Form plugin = new Form();
public Form1()
{
InitializeComponent();
plugin.Show();
}
private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
plugin.Close();
}
private void exitToolStripMenuItem_Click(object sender, EventArgs e)
{
Application.Exit();
}
}
The exception thrown is:
Exception thrown: 'System.InvalidOperationException' in mscorlib.dll
System.InvalidOperationException: Collection was modified; enumeration operation may not execute.
at System.Collections.ArrayList.ArrayListEnumeratorSimple.MoveNext()
at System.Windows.Forms.Application.ExitInternal()
at System.Windows.Forms.Application.Exit(CancelEventArgs e)
at System.Windows.Forms.Application.Exit()
at WindowsFormsApplication2.Form1.exitToolStripMenuItem_Click(Object sender, EventArgs e)

You don't need Application.Exit() in exitToolStripMenuItem_Click(). Calling Application.Exit, will close and dispose the form, while resuming the execution at exitToolStripMenuItem_Click, ObjectDisposedException would be thrown. Also, System.InvalidOperationException would be thrown as Windows Forms collection has been modified.

RuntimeBinderException occured in use dynamic keyword

I have a silverlight 5 application running in Out-Of-Browser mode and with elevated trust mode. I have added a button with the below mentioned click handler code.
private void Button_Click(object sender, RoutedEventArgs e)
{
using (dynamic shell = AutomationFactory.CreateObject("WScript.Shell"))
{
shell.Run(#"C:\windows\notepad.exe");
}
}
Upon executing the application and clicking on the button, I am getting a RuntimeBinderException stating
'object' does not contain a definition for 'Run'
I found a similar question posted here but no one has provided a solution for the same. Hence reposting the question.
Please help.

How can i find what cause a null exception ? I mean what line or where in the code the exception throw?

I'm running my program and after some time it's working it's throwing this exception:
I'm using directx in my program and also direct3d in the top of the form i did:
using Microsoft.DirectX.Direct3D;
using Microsoft.DirectX;
And i'm using in my program with Direct3D.Sprite and Device and Texture PresentParameters and DisplayMode all connected to the DirectX.Direct3D
And in the exception message it's saying something about OnLostDevice() and others. But it dosen't give any specific line or where in the code the problem is.
Is there any way to find what cause the problem ?
System.NullReferenceException was unhandled
HResult=-2147467261
Message=Object reference not set to an instance of an object.
Source=Microsoft.DirectX.Direct3DX
StackTrace:
at Microsoft.DirectX.Direct3D.Sprite.OnLostDevice()
at Microsoft.DirectX.Direct3D.Sprite.OnParentLost(Object sender, EventArgs e)
at System.EventHandler.Invoke(Object sender, EventArgs e)
at Microsoft.DirectX.Direct3D.Device.raise_DeviceLost(Object i1, EventArgs i2)
at Microsoft.DirectX.Direct3D.Device.Finalize()
InnerException:

For start put the Configuration of the project to Debug. At the moment you are in Release ! In your screenshot you can see it to the Continue button. After that you should Debug you project.
When you are in Debug, you can see the exact line which throw exception when you check the checkbox in Debug/Exceptions/Common Language Runtime Exceptions.

Error while unloading AppDomain. (Exception from HRESULT: 0x80131015)

I am having this error after using ReportViewer. Upon exit it has this error. Don't know what is causing this. I am using C#.

This is a reported Microsoft bug. There is a workaround for it - to call reportViewer.LocalReport.ReleaseSandboxAppDomain() method before closing the parent form.
Example:
private void frmMyForm_FormClosing(object sender, FormClosingEventArgs e)
{
reportViewer1.LocalReport.ReleaseSandboxAppDomain();
}
Reference: Weird behaviour when I open a reportviewer in WPF