Thank for your useful feedback. I got your explanation.
I have a small doubt when declare ComboBox with instruction " TComboBox Combo = CurrentDisplay.GetControl(“cobox”) as TComboBox"*
If I put this instruction inside the public void method, no error happen.
If I put this instruction outside the public void method, the error happen like below pictue
In the following explanation we will show you how to create a global ComboBox declaration. We will declare the variable Combo and Combo2 as of type TComboBox. The function InitializeCombo is then created, which aims to initialize the variable Combo and Combo2. In DisplayIsOpening, the function called InitializeCombo is executed to initialize the Combo and Combo2 variables and we did this example adding the values “123” and “abc”. In this way, the values are already inserted in the ComboBox.
public TComboBox Combo;
public TComboBox Combo2;
public void InitializeCombo()
Combo = CurrentDisplay.GetControl("cobox") as TComboBox;
public void InitializeCombo2()
Combo2 = CurrentDisplay.GetControl("Combo") as TComboBox;
public void DisplayOpening()
Outside of methods , you can only declare variables, to execute the GetControl() must be into a methods DisplayOpening, DispayIsOpen, DisplayClosing or any other methods called by those three methods.