在用户控制代码中我在顶部做：
int counter;
在构造函数中：
counter = 0;
在我做的MouseDown事件中：
private void listBox1_MouseDown(object sender, MouseEventArgs e)
{
int index = listBox1.IndexFromPoint(e.X, e.Y);
if (e.Button == System.Windows.Forms.MouseButtons.Right)
{
if (m_itemIndexes.Contains(index))
return;
m_itemIndexes.Add(index);
DrawItem(index);
counter += 1;
}
我在柜台上使用断点+ = 1;每当我点击鼠标右键时，就会看到它正在增长。
然后我在底部添加一个计数器的属性：
[Browsable(true)]
public int RedCounts
{
get { return counter; }
set
{
counter = value;
Refresh();
}
}
然后在顶部的Form1中我做了：
ListBoxControl lb1;
在构造函数中：
lb1 = new ListBoxControl();
然后在Form1的底部我添加了：
private void deleteSelectedLightningsToolStripMenuItem_Click(object sender, EventArgs e)
{
if (MessageBox.Show("Are you Sure you want to delete " + lb1.RedCounts + " the selected files ? Click Yes to Confirm and No to continue", "WinForm", MessageBoxButtons.YesNo, MessageBoxIcon.Question) == DialogResult.No)
{
}
else
{
}
}
但RedCounts的结果一直是0我不知道为什么。
编辑：
我发现如果我做而不是counter = 0;做counter = 1;而不是计数器+ = 1;做RedCounts + = 1;然后在RedCounts上使用断点，我看到计数器从1开始增长1. 1,2,3,4 ....
问题出在某种原因是在Form1中，当我使用断点单击deleteSelectedLightningsToolStripMenuItem_Click然后lb1.RedCounts因为某种原因它是1，可能是从属性或行计数器= 1获得值1;我不知道为什么。所以如果我设置counter = 121;那么lb1.RedCounts会告诉我121.奇怪。
这是带有计数器和RedCounts的完整用户控件：
/*----------------------------------------------------------------
* Module Name : ListBoxControl
* Description : Change listBox items color
* Author : Danny
* Date : 30/12/2012
* Revision : 1.00
* --------------------------------------------------------------*/
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Linq;
using System.Text;
using System.Windows.Forms;
/*
* Introduction :
*
* By default the color is red.
* Added a property to change the color.
* Right mouse click on item to change item color.
* Left mouse click on item to change the item color back.
* If the listBox is empty the control will be filled with 10 "Test" items.
* */
namespace Lightnings_Extractor // to check how and change the namespace to listBoxControl
{
public partial class ListBoxControl : UserControl
{
private Color m_MyListColor;
private List<int> m_itemIndexes = new List<int>();
private List<int> m_coloringItemIndexes = new List<int>();
private int counter;
public event EventHandler<ItemEventArgs> ItemRemoved;
public List<int> Indices
{
get { return m_itemIndexes; }
}
public ListBoxControl()
{
InitializeComponent();
counter = 1;
if (listBox1.Items.Count == 0)
{
for (int i = 0; i < 10; i++)
{
listBox1.Items.Add("Test " + i);
}
}
}
private void listBox1_MouseDown(object sender, MouseEventArgs e)
{
int index = listBox1.IndexFromPoint(e.X, e.Y);
if (e.Button == System.Windows.Forms.MouseButtons.Right)
{
if (m_itemIndexes.Contains(index))
return;
m_itemIndexes.Add(index);
DrawItem(index);
RedCounts += 1;
}
else if (e.Button == MouseButtons.Left)
{
if (!m_itemIndexes.Contains(index))
return;
m_itemIndexes.Remove(index);
DrawItem(index);
OnItemRemoved(index, listBox1.Items[index].ToString());
}
listBox1.SelectedIndex = index;
}
protected virtual void OnItemRemoved(int indx, string name)
{
EventHandler<ItemEventArgs> handler = ItemRemoved;
if(handler != null)
ItemRemoved(this, new ItemEventArgs() { Index = indx, Name = name});
}
private void listBox1_DrawItem(object sender, DrawItemEventArgs e)
{
m_MyListColor = MyListColor;
if (m_MyListColor.IsEmpty == true)
{
m_MyListColor = Color.Red;
}
bool selected = (e.State & DrawItemState.Selected) == DrawItemState.Selected;
if (m_itemIndexes.Contains(e.Index))
{
using (var brush = new SolidBrush(m_MyListColor))
{
e.Graphics.FillRectangle(brush, e.Bounds);
}
}
else
{
e.DrawBackground();
}
string item = listBox1.Items[e.Index].ToString();
e.Graphics.DrawString(item, e.Font, selected || m_itemIndexes.Contains(e.Index) ? Brushes.White : Brushes.Black, e.Bounds, StringFormat.GenericDefault);
if (selected)
e.DrawFocusRectangle();
}
private void DrawItem(int index)
{
Rectangle rectItem = listBox1.GetItemRectangle(index);
listBox1.Invalidate(rectItem);
}
[Browsable(true)]
public Color MyListColor
{
get { return m_MyListColor; }
set
{
m_MyListColor = value;
Refresh();
}
}
[Browsable(true)]
public ListBox MyListBox
{
get { return listBox1; }
set
{
listBox1 = value;
Refresh();
}
}
[Browsable(true)]
public int RedCounts
{
get { return counter; }
set
{
counter = value;
Refresh();
}
}
private void ListBoxControl_Load(object sender, EventArgs e)
{
this.listBox1.SelectedIndex = 0;
}
}
public class ItemEventArgs : EventArgs
{
public int Index { get; set; }
public string Name { get; set; }
}
}
答案 0 :(得分：2)
没有奇迹，请在代码中的某个位置右键单击counter - ＆gt; “查找所有参考”。如果您无法立即在结果中看到0，请在每次出现时设置断点，您很快就会找到它
答案 1 :(得分：-4)
您的计数器变量始终为零，因为每次调用类时，所有非静态对象都将再次实例化。您需要将计数器变量声明为静态，例如`static int counter = 0;
`