如何在第一次加载页面时获取下拉列表的选定项目? [英] How can I get the selected item of a dropdownlist, the first time my page loads?

问题描述

我正在寻找一种解决方案来获取 DropDownList 中的第一个选定项目.我想在页面第一次加载时获取它.

I'm looking for a solution to get the first selected item in a DropDownList. And I want to get it when the page loads for the first time.

提前致谢.

我在加载事件中调用此方法，但 ddlNiveau2 仍为空.我认为 ddlNiveau1.SelectedValue 未被访问.

I call this method at the Load-event but ddlNiveau2 remains empty. I think that ddlNiveau1.SelectedValue isn't accessed.

public void FillListNiveau2()
{
    ddlNiveau2.Items.Clear();
    foreach (var item in dBAL.GetListNiveau2(ddlNiveau1.SelectedValue))
    {
        ddlNiveau2.Items.Add(item.ToString());
    }
    RemoveDuplicateItems(ddlNiveau2);
}

推荐答案

有一个 DataBound 事件，它在数据绑定到下拉列表后触发.当您将数据源分配给下拉列表时，您需要在绑定到下拉列表的所有行之后选择项目

There is a DataBound event, which fires after the data is bound to the dropdown. As you are assigning the dataSource to your dropdown you need selected item after all the rows binded to dropdown

protected void DropDownList1_DataBound(object sender, EventArgs e)
{
    DropDownList1.SelectedValue // store it in some variable
}

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