索引超出范围异常。必须是非负数且小于集合的大小。参数名称：index [英] Index out of range exception. Must be non-negative and less than the size of the collection. Parameter name: index

问题描述

  string  greenColor =   G; 
 
 OleDbCommand cmd =  new  OleDbCommand（ 从LED_DATA中选择ID，其中color =' + greenColor +  ' ，con）; 
 OleDbDataReader reader = cmd.ExecuteReader（）; 
 
  while （reader.Read（））
 {
  int  r = Convert.ToInt16（reader [ 0 ]。ToString（））; 
  for （ int  c =  0 ; c <   8 ; c ++）
 {
 
 dataGridView1.Rows [r] .Cells [c] .Style.ForeColor = Color.Green; 
 
  if （ this  .dataGridView1.ColumnCount ==  7 ）
 {
  break ; 
} 
} 
 
} 

错误是：索引超出范围。必须是非负数且小于集合的大小。参数名称：索引





请尽快帮助我..我迫切需要它。

解决方案

  for （ int  c =  0 ; c <   7 ; c ++ ）

显然你的网格有7列，所以在你的循环中你必须从0到6。

要么你的table没有8列，或者您正在读取的行数，因为每行中的第一列与DataGridView的行数不匹配。



使用调试器：在行上放置一个断点

 dataGridView1.Rows [r] .Cells [c] .Style.ForeColor = Color.Green; 

并查看 r 和 c 的值来检查哪个是范围。

string greenColor = "G";

OleDbCommand cmd = new OleDbCommand("Select ID from LED_DATA where color='" + greenColor + "'", con);
            OleDbDataReader reader =   cmd.ExecuteReader();

            while (reader.Read())
            {
                int r = Convert.ToInt16(reader[0].ToString());
                for (int c = 0; c < 8; c++)
                {
                   
                    dataGridView1.Rows[r].Cells[c].Style.ForeColor = Color.Green;

                    if (this.dataGridView1.ColumnCount == 7)
                    {
                        break;
                    }
                }
                
            }

error is: Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index


Please help me as soon as possible.. I need it urgently.

解决方案

for (int c = 0; c < 7; c++)

Apparently your grid has 7 columns, so in your loop you have to go from 0 to to 6.

Either your table does not have 8 columns, or the number of rows you are reading as the first column in each row does not match the rows count for the DataGridView.

Use the debugger: put a breakpoint on the line

dataGridView1.Rows[r].Cells[c].Style.ForeColor = Color.Green;

And look at the value of r and c to check which is out of range.

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