Windows Forms - Control Arrays such as textboxes, buttons, and labels

[iknc4miles]

Hi all,

How would I go about making an array of controls such as textboxes for Windows Forms Programming using C++ on VC++ .NET 2003? I've tried porting the C# code from this site, but either I'm not a very good programmer or it doesn't work.

Do I need to create a class for it? I don't need to dynamically alter the number of textboxes, I just need to be able to reference each text box by an index number.

- iknc4miles

[RedSon]

That how-to is very thorough. Did you read through it or did you just cut and paste the code into your application? If you read through it was there a particular section that was confusing? That article will get you where you need to be but you have to go through it carefully.

[iknc4miles]

If you read through it was there a particular section that was confusing? That article will get you where you need to be but you have to go through it carefully.

Thanks for the quick reply.

I guess my biggest issue is converting C# syntax into managed C++. Many things, such as declaring a readonly instance of a form, I don't know how to do in C++. Instead, I just made and instance that points to a form:

private: System::Windows::Forms::Form *HostForm;

I will go through again and come back with some more details on syntax issues.

- iknc4miles

[iknc4miles]

Here's a step by step of my process in imitating the procedure found on that site. This should allow someone else to view what mistakes I'm making.

1. Open a new project under VC++ -->.NET-->>.NET Empty Project, name application ButtonArrayProject.


2. Add class by going to the Project Menu and selecting VC++ -->Generic-->Generic C++ Class
name = ButtonArray
base class = System::Collections::CollectionBase
access = public

I currently only have a header file "ButtonArray.h."


3. Add code to start class

public __gc class ButtonArray : public System::Collections::CollectionBase
{
    // Public Class ButtonArray
}

Build solution real quick to make sure everything is ok.


4. Add code for private form reference

public __gc class ButtonArray : public System::Collections::CollectionBase
{
    // Public Class ButtonArray
 
private: System::Windows::Forms::Form HostForm;
} 

5. Add code for AddNewButton method

public __gc class ButtonArray : public System::Collections::CollectionBase
{
    // Public Class ButtonArray
 
private: System::Windows::Forms::Form *HostForm;
 
public: System::Windows::Forms::Button *AddNewButton(void)
        {
            //Create New Instance of Button Class
            System::Windows::Forms::Button *aButton = new System::Windows::Forms::Button();
 
            //Add new button to collection's list
            this->List->Add(aButton);
 
            //Add the button to the controls collection of the form referenced by the HostForm field.
            HostForm->Controls->Add(aButton);
 
            //Set Initial properties for the button object.
            aButton->Top = Count + 25;
            aButton->Left = 100;
            aButton->Tag = this->Count;
            aButton->Text = String.Concat("Button ", this->Count.ToString());
 
            return aButton;
        }
}

I'll stop here, because I obviously have some syntax errors already. The code builds fine, but that means nothing because nothing's using it yet.

- iknc4miles

[iknc4miles]

If you read through it was there a particular section that was confusing?

Ok, here's a prt that has been giving me lots of problems. Creating the index property similar to their version.

How would I go about rewriting:

 public System.Windows.Forms.Button this [int Index]
{
get
{
return (System.Windows.Forms.Button) this.List(Index);
}
}

in C++?

- iknc4miles

[iknc4miles]

DONE! Took me all day but this code should work for any control you want to use in Windows Forms Programming in Managed Visual C++. Just replace TextBox with whatever control you want to use and set the control properties as well.

public __gc class textBoxArray : public System::Collections::CollectionBase
{
private: System::Windows::Forms::Form *HostForm;
 
public: System::Windows::Forms::TextBox *AddNewTextBox(void)
        {
 
            //Create a new instance of the TextBox class.
            System::Windows::Forms::TextBox *newTextBox = new System::Windows::Forms::TextBox();
// Add the textbox to the controls collection of the form referenced by the HostForm field.
            HostForm->Controls->Add(newTextBox);
 
            // Add the textbox to the collection's internal list.
            this->List->Add(newTextBox);
 
            // Set intial properties for textbox object.
// TODO: Rember to change these properties for your control!!!!!
            newTextBox->Top = this->get_Count() * 25;
            newTextBox->Left = 100;
            return newTextBox;
        }
public: textBoxArray(System::Windows::Forms::Form *host)
        {
            HostForm = host;
            this->AddNewTextBox();
        }
public: System::Windows::Forms::TextBox *get_TextBox(int index)
        {
            if(index <= this->Count && index > -1)
            {
                return dynamic_cast<System::Windows::Forms::TextBox*> (this->List->get_Item(index));
            }
            return dynamic_cast<System::Windows::Forms::TextBox*> (this->List->get_Item(this->get_Count() - 1));
        }
public: void Remove()
        {
            // Check to be sure there is a button to remove.
            if (this->get_Count() > 0)
            {
                // Remove the last button added to the array from the host from controls collection.  Note the use of the indexer in accessing the array.
                HostForm->Controls->Remove(this->get_TextBox(this->get_Count() - 1));
                this->List->RemoveAt(this->get_Count() - 1);
            }
        }
 
};

To use this class on a form, make sure to initialize it before adding or removing from the array.

private: System::Void Form1_Load(System::Object *  sender, System::EventArgs *  e)
         {
             MyTBoxes = new textBoxArray(this);
         }

Enjoy and feel free to improve and repost this code.

- iknc4miles