如何在asp.net中默认选择一个单选按钮

Question

我有一个单选按钮，我想默认选中默认的第一项。我该如何去做呢？以下是我单选按钮的源代码。

<asp:RadioButtonList ID="radRiskLevel" runat="server" RepeatDirection="Horizontal"> 
    <asp:ListItem Value="High">High</asp:ListItem> 
    <asp:ListItem Value="Mid">Mid</asp:ListItem> 
    <asp:ListItem Value="Low">Low</asp:ListItem> 
</asp:RadioButtonList> 

Answer 1

ASPX标记

<asp:RadioButtonList ID="radRiskLevel" runat="server" RepeatDirection="Horizontal"> 
    <asp:ListItem Value="High" Selected="True">Select</asp:ListItem> 
    <asp:ListItem Value="High">High</asp:ListItem> 
    <asp:ListItem Value="Mid">Mid</asp:ListItem> 
    <asp:ListItem Value="Low">Low</asp:ListItem> 
</asp:RadioButtonList>                  

Answer 2

选择默认经由ASPX标记值：

<asp:RadioButtonList ID="radRiskLevel" runat="server" RepeatDirection="Horizontal"> 
    <asp:ListItem Value="High" Selected="True">Select</asp:ListItem> 
    <asp:ListItem Value="Mid">Mid</asp:ListItem> 
    <asp:ListItem Value="Low">Low</asp:ListItem> 
</asp:RadioButtonList> 

通过C＃代码隐藏

选择默认值：

if (!IsPostBack) // prevent from selecting default value during postback 
{ 
    if (radRiskLevel.SelectedIndex == -1) //-1 is the indication of none selected 
    { 
     radRiskLevel.SelectedIndex = 0; // the index of items in radiobutton in the list you want to select 
     //radRiskLevel.Items.FindByText("Select").Selected = true; //can also be selected by text, need to pass text name as parameter 
     //radRiskLevel.Items.FindByValue("High").Selected = true; //can also be selected by value, need to pass value name as parameter 
    } 
}