How do I use my own function in a timer class? - winforms

Question

The code is taken from here:
https://learn.microsoft.com/en-us/dotnet/api/system.windows.forms.timer?view=windowsdesktop-6.0
private:
static System::Windows::Forms::Timer^ myTimer = gcnew System::Windows::Forms::Timer;
static int alarmCounter = 1;
static bool exitFlag = false;
// This is the method to run when the timer is raised.
static void TimerEventProcessor( Object^ /*myObject*/, EventArgs^ /*myEventArgs*/ )
{
myTimer->Stop();
// Displays a message box asking whether to continue running the timer.
if ( MessageBox::Show( "Continue running?", String::Format( "Count is: {0}", alarmCounter ), MessageBoxButtons::YesNo ) == DialogResult::Yes )
{
// Restarts the timer and increments the counter.
alarmCounter += 1;
myTimer->Enabled = true;
}
else
{
// Stops the timer.
exitFlag = true;
}
}
For example, after the line myTimer->Stop(); I want to use my own method. How do I identify it? E0020 ID "draw 1" is not defined.
System:: Void Practform::MyForm::draw1() {
. . .
}
Please tell me, because I'm a little stalled, since I've never worked with this.

Answer 1

I have a feeling that what you are bumping up against is attempting to invoke an instance method from a static method. To do so, you would need to have an instance of the class which has the method, e.g:
ref struct Foo {
void InstanceMethod() {}
static void StaticMethod() {
auto instance = gcnew Foo();
instance->InstanceMethod();
}
}
called like so:
Foo::StaticMethod();
However, taking the example code, it could be easier (and more appropriate) to change the static methods to instance methods, like so:
using namespace System;
using namespace System::Windows::Forms;
ref struct MyForm : Form {
Timer ^myTimer = gcnew Timer();
MyForm(void) {
myTimer->Tick += gcnew EventHandler(this, &MyForm::TimerEventProcessor);
myTimer->Interval = 5000;
myTimer->Start();
}
void TimerEventProcessor(Object ^, EventArgs ^) {
myTimer->Stop();
draw1();
}
void draw1() {
MessageBox::Show("Done", "Timer is done", MessageBoxButtons::OK);
}
};
called like so:
auto form = gcnew MyForm();
form->Show();
Notes:
I'm assuming that you've added the code from the example into your own class, called MyForm
I've used struct throughout instead of class to make everything public - you should use the appropriate access modifiers to your use case
The most notable change is the use of the EventHandler constructor which takes an instance of the handler as its first argument, and the method to execute as its second.
The advantages of using instance methods and properties are that:
you will have access to this in the draw1() method (given the name of the method, is likely to want to draw using the form instance), and
the Timer instance will be garbage collected as appropriate,