C# 获取组合框项目标记

困惑于我为什么会出现这个错误：

组合框

项：

private readonly string[] cbTexts = new string[] { "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday", "(Cleare)" };

动态

组合框

：

private void comboOptions()
        {
            cmb = new ComboBox[countWaiters];
            int width = 100;
            int height = 20;
            for (int i = 0; i <= 3; ++i)
            {
                newBox = new ComboBox();         
                newBox.Text = "(Request)";          
                newBox.Size = new Size(width, height);
                newBox.Location = new Point(0, (i * height));
                cmb[i] = newBox;
                cmb[i].SelectedIndexChanged += new EventHandler(cmb_SelectedIndexChanged);
                foreach (string cbText in cbTexts)
                {
                    cmb[i].Items.Add(cbText);
                }

                pnlRequests.Controls.Add(newBox);
            }            
        }

void cmb_SelectedIndexChanged(object sender, EventArgs e)
        {

            ComboBox senderCmb = (ComboBox)sender;

           int row = (int)senderCmb.Tag;
           //this is where the program crashes
           //more code located here that does something
         }

错误： 注意：此图像中的某些方法名称已更改，但不起任何作用

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您没有在给定代码中的任何位置设置

标记

属性，我不明白您为什么需要这样做。我怀疑您想要获取当前的

SelectedIndex

：

int row = senderCmb.SelectedIndex;

---

我漏掉了一行，犯了一个愚蠢的错误：

cmb[i].Tag = i;

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我看不出您在哪里设置tag属性，因此它为NULL也就不足为奇了（因此在尝试转换为int时会出现错误）。。愚蠢的错误！