如何計算 ListView 中的子項？

Question

我在 ListView 中有不同的條目。 我想計算條目（從第二列開始）。 output 應該在“Total”列下（見下圖，紅框）如何實現？ 使用此代碼，我只能訪問各個行：

for (int j = 1; j < listView1.Items[1].SubItems.Count; j++)               
{
   string s = listView1.Items[1].SubItems[j].Text;                   
}

非常感謝您的幫助！

Answer 1

這是你的解決方案

    //iterate through all rows                      
    for (int i = 0; i < listView1.Items.Count; i++)
    {
        //make sure that 5 subitems are present
        int missingSubitemsCount = 5 - listView1.Items[i].SubItems.Count;
        for (int j = 0; j < missingSubitemsCount; j++)
            listView1.Items[i].SubItems.Add(new ListViewItem.ListViewSubItem());

        int count = 0;

        //test columns 1-3
        for (int j = 1; j < listView1.Items[i].SubItems.Count - 1; j++)
        {
            //check if empty
            if (String.IsNullOrEmpty(listView1.Items[i].SubItems[j].Text) == false)
                count++;                    
        }                
            
        //update last column
        listView1.Items[i].SubItems[4].Text = count.ToString();
    }  

但是，我認為使用 DataGridView 和數據綁定會更好。 當項目變得更大時，直接在控件上操作可能會導致問題。 將數據與視圖分開更好

這是我將如何使用 DataGridView

    class MyItem
    {
        public string Name { get; set; }
        public string Property1 { get; set; }
        public string Property2 { get; set; }
        public string Property3 { get; set; }
        public int Total { get; set; }
    }

    private void button2_Click(object sender, EventArgs e)
    {
        var items = new List<MyItem>();

        items.Add(new MyItem
        {
            Name = "Books",
            Property1 = "A",
            Property2 = "B",
            Property3 = "C"
        });

        items.Add(new MyItem
        {
            Name = "Pencils",
            Property1 = "A",
            Property2 = "B",                
        });

        items.Add(new MyItem
        {
            Name = "Tapes",
            Property1 = "A",                
        });
       
        //iterate through all items
        foreach (var item in items)
        {
            //get list of MyItem properties starting with "Property"
            foreach (var property in typeof(MyItem).GetProperties().Where(u => u.Name.StartsWith("Property")))
            {
                //test if null or empty, increment Total if not
                if (property.GetValue(item) != null && String.IsNullOrEmpty(property.GetValue(item).ToString()) == false)
                    item.Total++;                    
            }

            //Alternative: Same calculation in one line
            item.Total = typeof(MyItem).GetProperties().Count(u => u.Name.StartsWith("Property") && u.GetValue(item) != null && String.IsNullOrEmpty(u.GetValue(item).ToString()) == false);
        }

        //bind items to DataGridView
        dataGridView1.DataSource = items;            
    }