在Gridview中动态创建的Dropdownlist不会在第二次触发事件

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        // 页面首次加载时的初始化操作
    }
    else
    {
        // 页面PostBack时的操作，包括重新绑定事件等
        BindDropdownlistEvents();
    }
}

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        // 动态创建和添加Dropdownlist控件
        DropDownList ddl = new DropDownList();
        ddl.ID = "ddl" + e.Row.RowIndex; // 设置唯一的ID
        // 添加Dropdownlist控件到Gridview的当前行
        e.Row.Cells[0].Controls.Add(ddl);
    }
}

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        // 动态创建和添加Dropdownlist控件
        DropDownList ddl = new DropDownList();
        ddl.ID = "ddl" + e.Row.RowIndex; // 设置唯一的ID
        // 添加Dropdownlist控件到Gridview的当前行
        e.Row.Cells[0].Controls.Add(ddl);

        // 绑定事件
        ddl.SelectedIndexChanged += new EventHandler(Dropdownlist_SelectedIndexChanged);
        ddl.AutoPostBack = true;
    }
}

protected void Dropdownlist_SelectedIndexChanged(object sender, EventArgs e)
{
    DropDownList ddl = (DropDownList)sender;
    GridViewRow row = (GridViewRow)ddl.Parent.Parent; // 获取当前行
    int rowIndex = row.RowIndex; // 获取当前行的索引

    // 处理相应的逻辑
}