Could you explain this for me please:
someformobj.BeginInvoke((Action)(() =>
{
someformobj.listBox1.SelectedIndex = 0;
}));
Could you tell me how can I use begininvoke
exactly?
What is Action
type?
Why there is blank brackets ()
?
And what does this mean =>
?
Action
is a Type of Delegate provided by the .NET framework. The Action
points to a method with no parameters and does not return a value.
() =>
is lambda expression syntax. Lambda expressions are not of Type Delegate
. Invoke requires Delegate
so Action
can be used to wrap the lambda expression and provide the expected Type
to Invoke()
Invoke
causes said Action
to execute on the thread that created the Control's window handle. Changing threads is often necessary to avoid Exceptions
. For example, if one tries to set the Rtf
property on a RichTextBox
when an Invoke is necessary, without first calling Invoke, then a Cross-thread operation not valid
exception will be thrown. Check Control.InvokeRequired
before calling Invoke.
BeginInvoke
is the Asynchronous version of Invoke
. Asynchronous means the thread will not block the caller as opposed to a synchronous call which is blocking.