How to call a non-static method inside a static class?

I have the following method / function and I need to call the method / function criaTimerTendencia that is within the class TagAnalogicaAtiva .

private static void VerificaEnvioDeMensagensSignalR(object sender, EventArgs e)
{
    if (ExisteTendenciaParaTag)
    {
        TagAnalogicaAtiva.criaTimerTendencia();//preciso chamar este metodo/função 
    }
}

Below is the code for the criaTimerTendencia()

class TagAnalogicaAtiva : TagAtiva
{
    public void criaTimerTendencia()
    {
        var tendencia = Processamento.PegaTendencia(IdTag);
        timer = new System.Timers.Timer(tendencia.TempoDeColeta);
        timer.Elapsed += insereTendenciaDB;
        timer.AutoReset = true;
        timer.Enabled = true;
     }
}

Only the following error is occurring:

  

An object reference is required for the non-static field, method, or property ‘TagAnalogicaAtiva.criaTimerTendencia ()’

How do I solve this problem?

In this case, it makes no difference whether the “outside” class is static or not. The problem with the code is that you are calling a non-static method of TagAnalogicaAtiva without first creating an instance of TagAnalogicaAtiva , this will never work.

Static members are accessible through the class rather than instances. Non-static members are accessible through instances of a given class.

Imagine that there exists in the class TagAnalogicaAtiva the FazerAlgo() and FazerAlgoEstatico() methods being respectively non-static and static.

To call the FazerAlgo() method, you must have one instance of TagAnalogicaAtiva , otherwise it is not necessary.

var tag = new TagAnalogicaAtiva();
tag.FazerAlgo();

TagAnalogicaAtiva.FazerAlgoEstatico(); // Funciona 

Then it is necessary to create an instance of TagAnalogicaAtiva to access the criaTimerTendencia() method, since it is non-static.

var tag = new TagAnalogicaAtiva();
tag.criaTimerTendencia();

To access the non-static method, you must instantiate an object of the class:

TagAnalogicaAtiva obj = new TagAnalogicaAtiva();
obj.criaTimerTendencia();