C# 如何将listBox1.SelectedIndex设置为0，使其仅对部分代码有效？

代码如下：

private void Lightnings_Mode_Load(object sender, EventArgs e)
        {
            this.Size = new Size(416, 506);
            this.Location = new Point(23, 258);
            listBoxIndexs();
            this.listBox1.SelectedIndex = 0; // This will make the listBox when showing it first time first item to be already selected !!!!!!
        }

        private void listBoxIndexs()
        {
            for (int i = 0; i < Form1.lightningsRegions.Count; i++)
            {

                    listBox1.Items.Add(Form1.lightningsRegions[i]);

            }
        }

        private void listBox1_SelectedIndexChanged(object sender, System.EventArgs e)
        {
            item = listBox1.SelectedItem.ToString();
            this.f1.PlayLightnings();
            f1.pdftoolsmenu();
            if (item != null && !pdf1.Lightnings.Contains(item.ToString()))
            {
                pdf1.Lightnings.Add(item.ToString());             
            }
        }

因为我想在单击按钮并显示/打开列表框后能够播放第一个项目

在第二个地方，我将项目添加到Lightings列表中，我希望只有在我首先单击任何项目时，它才会添加项目。 既然我这样做了：

this.listBox1.SelectedIndex = 0;

一旦我显示/打开列表框，它将自动向Lightings添加项目 我需要将其添加到列表中，仅当我首先单击一个项目时。另一方面，我也希望被选择索引=0，因为我希望它被选择，以便我可以播放它

---

那么，我如何区分用于播放的SelectedIndex=0和用于将项目添加到列表中的SelectedIndex=0？

如果我理解正确，您只需添加一个标志即可

bool allowItemAdding;

private void Lightnings_Mode_Load(object sender, EventArgs e)
{
    allowItemAdding = false; //setting false here because *sometimes* Load event is called multiple times.

    this.Size = new Size(416, 506);
    this.Location = new Point(23, 258);
    listBoxIndexs();
    this.listBox1.SelectedIndex = 0;  
    allowItemAdding = true; //set flag to true after selecting the index initially
}

private void listBox1_SelectedIndexChanged(object sender, System.EventArgs e)
{          
     item = listBox1.SelectedItem.ToString();
     this.f1.PlayLightnings();
     f1.pdftoolsmenu();
     if (allowItemAdding)
     {
         if (item != null && !pdf1.Lightnings.Contains(item.ToString()))
         {
             pdf1.Lightnings.Add(item.ToString());             
         }
     }
}

---

然后，该标志将保持为true，直到您将其显式更改为false，以便您可以控制何时应添加项或不添加项。

使用_-SelectionChangeCommitted而不是listBox1\u-SelectedIndexChanged

bool allowItemAdding;

private void Lightnings_Mode_Load(object sender, EventArgs e)
{
    allowItemAdding = false; //setting false here because *sometimes* Load event is called multiple times.

    this.Size = new Size(416, 506);
    this.Location = new Point(23, 258);
    listBoxIndexs();
    this.listBox1.SelectedIndex = 0;  
    allowItemAdding = true; //set flag to true after selecting the index initially
}

private void listBox1_SelectedIndexChanged(object sender, System.EventArgs e)
{          
     item = listBox1.SelectedItem.ToString();
     this.f1.PlayLightnings();
     f1.pdftoolsmenu();
     if (allowItemAdding)
     {
         if (item != null && !pdf1.Lightnings.Contains(item.ToString()))
         {
             pdf1.Lightnings.Add(item.ToString());             
         }
     }
}