c# - 为以大写字母开头的gridview的所有单元格值添加背景色

Question

我是 ASP.NET 和 C# 的新手。我想为以大写字母开头的 gridview 的所有单元格值添加背景颜色。这是我的源代码:

protected void OnRowDataBound(object sender, GridViewRowEventArgs e)
{
            if (e.Row.RowType == DataControlRowType.DataRow)
            {
                TableCell cell = e.Row.Cells[2];
                string entity = cell.Text.ToString();
                if (entity[0] >= 'A' && entity[0] <= 'Z')
                {
                  cell.BackColor = Color.Yellow;
                }  
            }
 }

但是我得到了这个错误:

Index was outside the bounds of the array.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.IndexOutOfRangeException: Index was outside the bounds of the array.

Source Error: 


Line 85:                 TableCell cell = e.Row.Cells[1];
Line 86:                 string entity = cell.Text.ToString();
Line 87:                 if (entity[0] >= 'A' && entity[0] <= 'Z')
Line 88:                 {
Line 89:                   cell.BackColor = Color.Yellow;

Source File: c:\Users\Eric\Default.aspx.cs    Line: 87 

请帮我解决这个错误

谢谢大家

Answer 1

问题出在这一行:

if (entity[0]...

如果单元格的值为 null 或空，则实体将没有任何元素。这会给你超出范围的异常。

您可以通过首先检查数组中是否有任何元素来解决这个问题。

if (!string.IsNullOrEmpty(entity) && entity[0] >= 'A' && entity[0] <= 'Z')
{
    //your code here
}

这样它只会检查大写字母是否确实存在