In this post we are going to see why there is no nothing check code is not present for the events in the VB.Net. In Generally while we code in c#, we can see the code like check the event not to be null, then we will fire it. But in VB.Net
we can't find a code like this.
Normally how we raise a event in VB.Net
Declare the Event
***********************
In the Above code we can see that before the RaiseEvent Directly call the Events instead of checking the null, this is why means,By default RaiseEvent will check for Nothing before fire the Event, so we don't need to worry about this, but if there is a need to check whether the event is hooked or not , then how we can find this ?
RaiseEvent doesn't have any return type to find whether Event is there or not, then how we can find this whether Event is hooked, By Default a variable is created with EventName + 'Event' , we can use that variable to check for Nothing
For Example: OnHeaderClickEvent
Declare the Event
***********************
From this post you can see why there is no Nothing check for Events and how we can check the Nothing in Events in Vb.Net
we can't find a code like this.
Normally how we raise a event in VB.Net
Public Delegate Sub
CheckBoxHeaderClickHandler(sender As Object, e As CheckBoxHeaderCellEventArgs)
***********************
Public Event OnHeaderClick As CheckBoxHeaderClickHandler
Calling the Event
***********************
RaiseEvent OnHeaderClick(Me, CHECK_ARGS)In the Above code we can see that before the RaiseEvent Directly call the Events instead of checking the null, this is why means,By default RaiseEvent will check for Nothing before fire the Event, so we don't need to worry about this, but if there is a need to check whether the event is hooked or not , then how we can find this ?
RaiseEvent doesn't have any return type to find whether Event is there or not, then how we can find this whether Event is hooked, By Default a variable is created with EventName + 'Event' , we can use that variable to check for Nothing
For Example: OnHeaderClickEvent
Public Delegate Sub
CheckBoxHeaderClickHandler(sender As Object, e As CheckBoxHeaderCellEventArgs)
***********************
Public Event OnHeaderClick As CheckBoxHeaderClickHandler
Calling the Event
***********************
If OnHeaderClickEvent IsNot Nothing Then
RaiseEvent OnHeaderClick(Me, CHECK_ARGS)
End If
From this post you can see why there is no Nothing check for Events and how we can check the Nothing in Events in Vb.Net
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