C# multithreading - 'System.Reflection.TargetInvocationException'
I started multithread programming in C# (WPF) few days ago and here is a problem which I can't solve... I'm using this piece of code:
void timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
{
Random foodPosition = new Random();
double x,y;
Size size = new Size(30,30);
bool foodCreated = false;
Ellipse food = null;
Food foodObject = null;
Thread foodThread = new Thread(new ThreadStart(() =>
{
field.Dispatcher.Invoke(new Action(() =>
{
food = new Ellipse();
food.Fill = GenerateColor();
food.Width = size.Width;
food.Height = size.Height;
x = foodPosition.Next(0, (int)(playGroundSize.Width - size.Width) + 1);
y = foodPosition.Next(0, (int)(playGroundSize.Height - size.Height) + 1);
if (IsFree(x, y, size, 0))
{
playField.Children.Add(food);
Canvas.SetTop(food, y);
Canvas.SetLeft(food, x);
foodObject = new Food(food, new Point(x, y));
foodCollection.Add(foodObject,0);
foodCreated = true;
}
}));
if (foodCreated)
{
for (int i = 0; i < foodAliveTime; i++)
{
Thread.Sleep(1000);
foodCollection[foodObject]++;
}
field.Dispatcher.Invoke(new Action(() =>
{
playField.Children.Remove(foodObject.FoodObject);
//threadList[foodObject].Abort();
}));
}
}));
foodThread.Start();
}
I think that the problem comes from the upper code. There is an exception thrown after about a minute work of my program. This is the exception:
An unhandled exception of type 'System.Reflection.TargetInvocationException' occurred in mscorlib.dll
Additional information: Exception has been thrown by the target of an invocation.
And after tha开发者_C百科t I'm receiving this message:
There is no source code available for the current location.
I know that my source code is a little bit ugly, I'm going to make it better after I solve this problem. Could you please tell me how I can fix the it?
I suppose that problem is in line:
field.Dispatcher.Invoke
You should put this part of code inside try/catch block and catch
TargetInvocationException
This exception can provide more information what the problem is (pay attention to its InnerException
).
P.S.
Put the whole body of function inside try/catch block; and catch not only TargetInvocationException
but at least System.Exception
after it.
To troubleshoot this type of error, get the inner exception. It could be due to a number of different issues.
try
{
// code causing TargetInvocationException
}
catch (Exception e)
{
if (e.InnerException != null)
{
string err = e.InnerException.Message;
}
}
When dealing with System.Reflection.TargetInvocationException inner exception should also be looked at . That might tell you where the exception.
Also do you have to do Thread foodThread = new Thread(new ThreadStart(() =>
If I was use I will use Threadpool.QueueworkerItem
or if you have .Net Framework 4.0 use
Task.Factory.StartNew()
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