How can I associate integer values with items?

Applies To: C++Builder 1 or higher
Category: Knowledge Base

Every component in C++Builder allows me to specify a Tag property. The compiler does not use this field but I can store in it my own information. Is it possible to associate an integer value with an item?

 

1.

  Start a new project using File | New Application.

 

2.

  Add a ListBox. Edit its OnClick event:

 

void __fastcall TForm1::ListBox1Click(TObject *Sender)

{

    if(ListBox1->ItemIndex != -1)

    {

        int tag = ListBox1->Perform(LB_GETITEMDATA,

            ListBox1->ItemIndex, 0);

        ShowMessage(tag);

    }

}

 

3.

  Add a Button. Edit its OnClick event:

 

void __fastcall TForm1::Button1Click(TObject *Sender)

{

    int x;

 

    x = ListBox1->Items->Add("First");

    ListBox1->Perform(LB_SETITEMDATA, x, 55);

    x = ListBox1->Items->Add("Second");

    ListBox1->Perform(LB_SETITEMDATA, x, 56);

    x = ListBox1->Items->Add("Third");

    ListBox1->Perform(LB_SETITEMDATA, x, 57);

}

 

You can send an LB_SETITEMDATA message to set a 32-bit value associated with the specified item in a list box.

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