Question

I got a problem with ListView in System.Windows.Forms, that i can’t handle it on myself, begging for help or a hint where do I do wrong?
Description:
– I have a class – name it cListViewItem (‘c’ from custom), that inherits from standard ListViewItem, but stores my own data handling class. Now, after adding cListViewItem to a ListView class using ListView.items.Add( ) i don’t seem to have any control over the item’s name.
– fragments of my source (lil changed for the purpose of this post)

using System.Windows.Forms;
cListViewItem:ListViewItem
{
  // gives a basic idea
  public cListViewItem( myclass DataStorage )
  {
    // constructor only stores DataStorage to a local variable for further use;
    this._storage = DataStorage;
  }
  protected myclass _storage;
  // and there goes the fun:
  // I thought that ListView class uses .Text property when drawing items, but that is not truth
  // my idea was to 'cheat' a little with:
  new public String Text
  {
    get
    {
      // overriding a getter should be enough i thought, but i was wrong
      return( some string value from DataStorage class passed via constructor );
      // setter is not rly needed here, because data comes from this._storage class;
      // in later stages i've even added this line, to be informed whenever it's called ofc before return( ); otherwise VisualStudio would not compile
      MessageBox.Show( "Calling item's .Text property" );
      // guess what? this message box NEVER shows up;
    }
  }
}

I see that’s important to use .Text setter, but constructor is the last moment i can do it, right after creation cListViewItem is being added to ListView Items property and displayed, so there’s no place to call .Text = “” again.
My piece of code only works when I set all things in cListViewItem ‘s constructor like:

public cListViewItem( myclass DataStorage )
{
   this._storage = DataStorage;
   this.Text = DataStorage.String1;
   // and if I add subitems here, I will see em when the ListView.View property be changed  to View.Details
}

So am I blind or what? when I use cListViewItem.Text = “string” I will see ‘string’
in the ListView but when I just override .Text getter i can’t see the items 🙁

ListView class gives the flexibility of showing items the way I need. I wanted to create a class that will bind my custom data storage class with a ListView class. In the next stage of my application I want to bind a form for selected item in a ListView, that will allow me change item’s (my custom class) values. That’s why i wanted to make each ListViewItems item remembering corresponding custom data storage class.
Names shown in ListView will never be uniqe, so multiple same names all allowed, but items will differ by a id value (database-wise);
I just can’t figure out why using ListViewItem.Text setter does the job, altho ListView class does not use ListViewItem.Text getter for displaying items (my MessageBox never pops up)??
Pls help.

Answer 1

The main problem here is that you are hiding the property with the new keyword. The original property is not virtual (“overwritable”) so it is NOT overwritten but shadowed.

Read here for more information.