Index was out of range. Must be non-negative and less than the size of the collection error

Question

hi i am getting this error when running this piece of code and cant figure it out. cheers:

      DataGridView1.SelectionMode = DataGridViewSelectionMode.FullRowSelect;
        try
        {
            for (int i = 0; i <= (DataGridView1.Rows.Count); i++)
            {

                if (DataGridView1.Rows[i].Cells[2].ToString().Equals(returnID))
                {
                   SignIn_Time(updateCmd, OLEDB_Connection, varName, varID, varTime);
                   break;
                }
            }
        }
        catch
        {

Answer 1

由于从零开始的索引，它应该小于计数，而不是等于：

i < DataGridView1.Rows.Count

Answer 2

The error is clear on what's going on:

[index] non-negative and less than the size of the collection.

Replace <= with < in the loop header:

for (int i = 0; i < (DataGridView1.Rows.Count); i++) {
    ...
}

In addition, you need to make sure that each row has at least three cells, because you are accessing the third cell in a row: Cells[2]