Question

我已编写此代码用于拆分字符串

 protected void DropDownList2_SelectedIndexChanged(object sender, EventArgs e)
{
    string oldstr = DropDownList2.SelectedItem.Value;

    string[] exp = System.Text.RegularExpressions.Regex.Split(oldstr, "-");
    int int1 = Convert.ToInt32(exp[0]);
    int int2 = Convert.ToInt32(exp[1]);
}

它给了我异常

“索引超出了数组的范围。”

在第int int2 = Convert.ToInt32(exp[1]);行

        <asp:DropDownList ID="DropDownList2" runat="server" AutoPostBack="True" 
                onselectedindexchanged="DropDownList2_SelectedIndexChanged">
                <asp:ListItem></asp:ListItem>
                <asp:ListItem Value="1-2">1-2 years</asp:ListItem>
                <asp:ListItem Value="3-4 ">3-4 years</asp:ListItem>
                <asp:ListItem Value="5-7">5-7 years</asp:ListItem>
            </asp:DropDownList>

Answer 1

更新你这样标记

<asp:DropDownList ID="DropDownList2" runat="server" AutoPostBack="True" 
                onselectedindexchanged="DropDownList2_SelectedIndexChanged">
         <asp:ListItem Value="0-0"></asp:ListItem> // add 0 and 0
        <asp:ListItem Value="1-2">1-2 years</asp:ListItem>
        <asp:ListItem Value="3-4">3-4 years</asp:ListItem>//remove space after 4 
        <asp:ListItem Value="5-7">5-7 years</asp:ListItem>
</asp:DropDownList>

而不是转换如下所示使用TryParse，还检查分裂数组的长度

//string[] exp = System.Text.RegularExpressions.Regex.Split(oldstr, "-");
//use string split rathre than using regular expression because character split is 
// faster than regular expression split
string[] exp = oldstr.Split('-');
if(exp.Length>0)
{
  int int1;
  if(int.TryParse(exp[0], out num1))
 { // further code }
  int int2;
 if(int.TryParse(exp[1], out num1))
 { // further code }
}

Answer 2

Value的第一个元素的DropDownList是空字符串，当你绑定时，第一个元素会触发SelectedIndexChanged事件，并且拆分它将为你提供零元素数组。在通过索引访问数组之前在索引上应用条件。

int int1 = 0;
if(exp.Length > 0)
     int1 = Convert.ToInt32(exp[0]);

int int2 = 0;
if(exp.Length > 1)
     int2 = Convert.ToInt32(exp[1]);

或者为第一个元素添加值，例如0 - 1年

<asp:ListItem Value="0-1">Upto one one year</asp:ListItem>

分割字符串中的索引超出范围异常

2 个答案: