C# 如何将 DropDownList 中的项目设置为默认值？
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How do I set an item in a DropDownList as the default value?
提问by Nevin Mathai
How do I set an item in a DropDownList as the default value in ASP.NET?
如何将 DropDownList 中的项目设置为 ASP.NET 中的默认值？
SomeDropDownList.DataSource =GetSomeStrings();
采纳答案by Ariel
There are two ways to do it:
有两种方法可以做到：
Set the
SelectedValueto the value you want as the defaultDropDownList.SelectedValue = "value". This is very simple but will result in an error if the dropdown already has aSelectedValueSet the actual item
DropDOwnList.Items.FindByValue("value").Selected = true;which should not result in an error in case there already is a selected item.
将 设置为
SelectedValue您想要的值作为默认值DropDownList.SelectedValue = "value"。这很简单，但如果下拉菜单已经有一个SelectedValue设置实际项目
DropDOwnList.Items.FindByValue("value").Selected = true;，如果已经存在选定项目，则不应导致错误。
回答by SLaks
Set the SelectedValueproperty
设置SelectedValue属性
回答by alexphi
You can bind the DropDownList to the data source, and then set the SelectedValue:
您可以将 DropDownList 绑定到数据源，然后设置 SelectedValue：
someDropDownList.DataSource = GetSomeStrings();
someDropDownList.DataBind();
someDropDownList.SelectedValue = "default value";
You could also select the default item by index, using the SelectedIndex property:
您还可以使用 SelectedIndex 属性按索引选择默认项：
someDropDownList.SelectedIndex = 0;
