请帮我修复此错误（在列表框中显示） [英] please help me fix this error(displaying in listboxes)

问题描述

这里是错误>

**************例外文字**************

System.ArgumentOutOfRangeException：InvalidArgument ='0'的值对'SelectedIndex'无效。

参数名称：SelectedIndex



我的代码>

here is the error>
************** Exception Text **************
System.ArgumentOutOfRangeException: InvalidArgument=Value of '0' is not valid for 'SelectedIndex'.
Parameter name: SelectedIndex

my code>

DataSet st = new DataSet();
           string strConnectionString = "Data Source=JAMES-PC\\SQLEXPRESS;Initial Catalog=staff;Integrated Security=True";

           SqlConnection objconnection = new SqlConnection(strConnectionString);
           using (SqlCommand cmd = new SqlCommand("SELECT  [name] FROM [staff1]",
           objconnection))
           {
               using (SqlDataAdapter adapter = new SqlDataAdapter(cmd))
               {
                   adapter.Fill(st);
               }
           }

           var empList = st.Tables[0].AsEnumerable().Select(dataRow =>

           dataRow.Field<string>("name")).ToList();

           listBox1.SelectedIndex = 0;
           listBox1.Update();

我不明白这个问题。它在10分钟前工作但现在却没有？我真的很困惑任何帮助都是apreciated

I dont understand the issue.It worked 10 mins ago but now it doesn't? I am really confused any help would be apreciated

推荐答案

这意味着你试图在列表中选择0项目计数。如果您至少有一个项目，则索引0将有效。只需1）使用调试器; 2）不要通过索引来解决任何事情而不检查计数，这将给出你应该检查的指数0到 count - 1 的有效范围。 />

-SA

It means that you are trying to select an item in a list with 0 item count. If you had at least one item, the index 0 would be valid. Just 1) use the debugger; 2) don't address anything by index without checking the count, which would give your the valid range of indices 0 to count − 1, which you should check up.

—SA

这篇关于请帮我修复此错误（在列表框中显示）的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！