Provider, injectables: comprehension question

Ionic Framework
1

Hi,

I am a bit onfused about the scope of providers and/pr injectables;
I wanted to build a provider wrapping some often used stuff, like a confirmation dialog before deleting, which initializes the deletion when confirmed.

My code in the provider:

  constructor(public alertCtrl: AlertController) {  }

  ShowConfirmation(title, message, ok, okText, cancelText) {
    let confirm = this.alertCtrl.create({
      title: title,
      message: message,
      buttons: [
        {
          text: cancelText,
          role: 'cancel',
          handler: () => {
            // nothing
          }                
        },
        {
          text: okText,
          role: 'cancel',
          handler: () => {
            ok();
          }                
        }
      ]
    });
    confirm.present();
  }

the call:

    this.utils.ShowConfirmation("Delete", "Do you really want to delete this item?", this.deleteItem, "Delete", "Cancel");

the deleteItem()

  deleteItem() {
    let idx = this.items.findIndex(x => x.MD5 == this.key);
    if (idx != -1) {
      this.items.splice(idx, 1);
      this.Data.storage.set('myItems', JSON.stringify(this.items)).then(() => {
        this.refreshData();
      });
    }
  }

The error I get: Cannot read property ‘items’ of undefined
Okay, so the page from wher I call the method is not in the scope. Why? Amd how do I do this correctly? How do I get the correct scope in a provider?

thnx