如何通过显示文本在 ASP.NET 下拉列表中设置所选项目? [英] How can you set the selected item in an ASP.NET dropdown via the display text?

问题描述

我有一个通过数据绑定填充的 ASP.NET 下拉列表.我的文本与我要选择的列表项的显示文本相匹配.我显然不能使用 SelectedText(仅限 getter)而且我不知道索引，所以我不能使用 SelectedIndex.我目前正在通过遍历整个列表来选择项目，如下所示:

ASP:

代码:

ddItems.DataSource = myItemCollection;ddItems.DataTextField = "名称";ddItems.DataValueField = "Id";foreach(ddItems.Items 中的 ListItem 项目){if (item.Text == textToSelect){item.Selected = true;}}

有没有办法在不遍历所有项目的情况下做到这一点?

解决方案

你可以试试:

ddItems.Items.FindByText("Hello, World!").Selected = true;

或者:

ddItems.SelectedValue = ddItems.Items.FindByText("Hello, World!").Value;

请注意，如果您不确定是否存在与您的显示文本匹配的项目，您可能需要检查 FindByText() 的结果是否为 null.>

请注意，我在多选列表(例如 CheckBoxList)上使用第一种方法来添加额外的选择.我使用第二种方法来覆盖所有选择.

I have an ASP.NET dropdown that I've filled via databinding. I have the text that matches the display text for the listitem I want to be selected. I obviously can't use SelectedText (getter only) and I don't know the index, so I can't use SelectedIndex. I currently am selecting the item by iterating through the entire list, as show below:

ASP:

<asp:DropDownList ID="ddItems" runat="server" /> 

Code:

ddItems.DataSource = myItemCollection;
ddItems.DataTextField = "Name";
ddItems.DataValueField = "Id";

foreach (ListItem item in ddItems.Items)
{
    if (item.Text == textToSelect)
    {
        item.Selected = true;
    }
}

Is there a way to do this without iterating through all the items?

解决方案

You can try:

ddItems.Items.FindByText("Hello, World!").Selected = true;

Or:

ddItems.SelectedValue = ddItems.Items.FindByText("Hello, World!").Value;

Note that, if you are not certain that an items exists matching your display text, you may need to check the results of FindByText() for null.

Note that I use the first approach on a multiple-select list, such as a CheckBoxList to add an additional selection. I use the second approach to override all selections.

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