How do I reference a control's properties?

I am new to VC++ but not to programming.

I am trying to change the Text property off a textbox when I click a button. However I cannot determine the proper syntax to reference the text field.

Form name - Form1

Textbox name - Textbox1

Button name - Button1

In Button1.Click I tried the following - all of which fail compile

Form1::Textbox1->Text = "Hello World"; /* error C2227 */

If you're inside a form event (like a button click), then something lik this should work:

this->Textbox1->Text = "Hello World";

(provided your casing is correct).

In traditional Windows.Forms programming, every form is created as an instance, and event handlers are member functions (called methods). All instance functions have a hidden "this" parameter that points to the current instance. The -> is used because both TextBox and String are reference types, accessed via pointers (they actual data is always on the heap).

Conventionally, the "this->" part is skipped, but it's useful for illustration of what's truly happening, so I always use it :)

-Ryan / Kardax

I tried that and got the following errors:

It absolutely matters where the code is placed :)

This "this" pointer only works in instance methods, and the code I provided will only work if that instance method is on your form class.

If you want to change the content of a text box from a global function, a reference to the form must be stored in a global location and the text box field must have public or internal access. Then you would simple replace "this" with whatever your global variable is named.

-Ryan / Kardax

PS: Global functions and variables should be avoided in any object-oriented C++ project, which includes just about anything involving .NET.

If you're using .Text instead of ->Text, it's guaranteed to fail because Text is a String--a reference type.

You have to place the code I provided -inside- the Form1 (or whatever you called it) class for it to work. If it's outside, it's treated as a global function and the "this" parameter won't be available.

I encourage you to get a book on C++/CLI so you can get past these stumbling blocks. With your programming background, you should be able to pick things up quickly :)

-Ryan / Kardax