Invoke & Invoke.Required 1

[V00D00]

Can someone give me an example of invoke and invoke.required used to show and hide a form?

VD

 

[JurkMonkey]

InvokeRequired bascially tells you if the thread that is calling the method is the thread where the gui component exists.

So if you are calling a method on a GUI item, you check if InvokeRequired is true. If it is, you invoke the call on itself using a delgate.


public void DisplayMyForm()
{
if (this.InvokeRequired)
{
this.Invoke(new DisplayEventHandler(DisplayMyForm), new object[]);
}
else
{
this.show;
}
}

public delegate void DisplayEventHandler();

 

[V00D00]

Please excuse my ignorance with this. Let me give you my example. My main form is checking for a connection state with a network service.

void AASRef_CallStatus(string Message)
{
switch (Message){
case "Attached":
loginpage.Show();
break;
case "Logged on":
loginpage.hide();
break;
}
}

I am trying to apply the example that you posted but am a little unsure about how exactly to do it. Using the code provided can you please demonstrate?

 

[JurkMonkey]

Add new methods to your LoginPage Form called DisplayForm() and HideForm().

Add the code I provided above in each of these methods. In the DisplayForm() use this.Show() In the HideForm() use this.Hide() or this.Close()

 

[V00D00]

I should also add that this is a second form I am trying to invoke not the main form.

 

[chiph]

Doesn't make any difference.

The key thing to know here is those methods are used when the calling code is running on a different thread than the one that created the form.

Chip H.


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