Question

我有一个包含两个只读文本框和两个按钮的MainForm，它们打开了用户想要显示的PizzaCreatorForms的多个实例，其他按钮显示了PizzaOrdersListViewForm的一个实例。两个只读文本框记录了PizzaCreatorForm的实例数量（此部分有效），另一个跟踪正在创建的项目数量（这也有效）。

我应该补充说，PizzaCreatorForm创建的每个对象都会添加到List＆lt;＆gt;中，就像在PizzaOrdersListViewFrom listView.Items控件中一样。 MainForm和PizzaOrderListViewForm中还有一个清除按钮，用于清除List＆lt;＆gt;。

我的代码有效，但我遇到了两个问题。

每当在列表＆lt;＆gt;中添加新对象时，如果我希望它从1开始，则从0开始。
每当我清除List＆lt;＆gt;使用PizzaOrderListViewForm中的清除按钮，清除listview控件项，但文本框显示相同的数字

这是我试图用于＃2的自定义事件：

的MainForm

    public partial class Form1 : Form
    { 
       public static List<Pizza> pizzaList = new List<Pizza>();
       public List<Pizza> PizzaList
       {
           get { return pizzaList; }
           set { pizzaList = value; }
       }

       //Where PizzaOrdersListViewForm is instantiated
       private void displayOrdersToolStripMenuItem_Click(object sender, EventArgs e)
       {
           PizzaOrdersListViewForm orderListV = new PizzaOrdersListViewForm();


       }
       //Where PizzaCreatorForm is instantiated
       private void newPizzaOrder_Click(object sender, EventArgs e)
       {
           PizzaCreatorForm pizzaForms = new PizzaCreatorForm(this);
           pizzaForms.PizzaInList += PizzaInListHandler;
           pizzasCreatedCounterTextBox.TextChanged += PizzaInListHandler;
       }

       public void PizzaInListHandler(object sender, EventArgs e)
       {
           pizzasCreatedCounterTextBox.Text = pizzaList.Count.ToString();        
       }
       public void ClearMainListChangeHandler(object sender, EventArgs e)
       {  
           pizzaList.Clear();
       }
    }

PizzaCreatorForm

    public partial class PizzaCreatorForm : Form
    {
       public EventHandler PizzaInList;

       public Pizza Order
       {
           //Code that assigns Pizza class member variables to control values
       }

       Form1 MainForm = null;

       public PizzaCreatorForm(Form1 mForm)
       {
            InitializeComponent();
            MainForm = mForm
       }

       private void orderNewPizaaToolStripButton_Click(object sender, EventArgs e)
       {
            if(PizzaInList != null)
            {
                PizzaInList(this, new EventArgs());
            }

            MainForm.PizzaList.Add(Order);

            Order = new Pizza();
       }
    }

PizzaOrdersListViewForm

    public partial class PizzaOrdersListViewForm : Form
    {
       public EventHandler ClearMainList;

       Form1 mainForm = null;

       public PizzaOrdersListViewForm(Form1 TheMain)
       {
          InitializeComponent();
          mainForm = TheMain;
       }

       private void clearToolStripButton_Click(object sender, EventArgs e)
       {
          if(ClearMainList != null)
          {
              ClearMainList(this, new EventArgs());
          }
          ClearMainList += mainForm.ClearMainListChangeHandler;
          pizzaListView.Items.Clear();

       }

    }

Answer 1

我所要做的就是将PizzaOrdersListViewForm ClearMainList EventHandler订阅到MainForm中displayOrdersToolStripMenuItem_Click方法内的自定义PizzaInListHandler方法。

private void displayOrdersToolStripMenuItem_Click(object sender, EventArgs e)
{
     PizzaOrdersListViewForm orderListV = new PizzaOrdersListViewForm();
     orderListV.ClearMainList += ClearMainListChangeHandler;
     orderListV.ClearMainList += PizzaInListHandler;
}

我弄清楚了pizzaList.Count的错误。当我应该选择带回List＆lt;＆gt;内的元素总数的Count时，我不小心使用了计算每个项目序列的Count。

更新列表中项目的文本框控件数＆lt;＆gt;当使用自定义事件C＃

1 个答案: