How can I fix this error:
Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index
In this code:
dataGridView1.AllowUserToAddRows = false;
dataGridView1.Columns.Add("ID", "ID");
dataGridView1.Columns.Add("Firstname", "Firstname");
dataGridView1.Columns.Add("MI", "MI");
dataGridView1.Columns.Add("Lastname", "Lastname");
dataGridView1.Columns.Add("Username", "Username");
dataGridView1.Columns.Add("Rights", "Rights");
c.Open();
OleDbCommand cmd = new OleDbCommand();
cmd.Connection = c;
cmd.CommandText = "SELECT * From Account";
OleDbDataReader reader = cmd.ExecuteReader();
while (reader.Read())
{
    dataGridView1.Rows[dataGridView1.Rows.Count - 1].Cells["ID"].Value = reader[0].ToString();
    dataGridView1.Rows[dataGridView1.Rows.Count - 1].Cells["Firstname"].Value = reader[1].ToString();
    dataGridView1.Rows[dataGridView1.Rows.Count - 1].Cells["MI"].Value = reader[2].ToString();
    dataGridView1.Rows[dataGridView1.Rows.Count - 1].Cells["Lastname"].Value = reader[3].ToString();
    dataGridView1.Rows[dataGridView1.Rows.Count -    1].Cells["Username"].Value = reader[7].ToString();
    dataGridView1.Rows[dataGridView1.Rows.Count - 1].Cells["Rights"].Value      = reader[9].ToString();
}
c.Close();
                You'll get the Indexerror: list index out of range error when you try and access an item using a value that is out of the index range of the list and does not exist. This is quite common when you try to access the last item of a list, or the first one if you're using negative indexing.
The Python "IndexError: list assignment index out of range" occurs when we try to assign a value at an index that doesn't exist in the list. To solve the error, use the append() method to add an item to the end of the list, e.g. my_list.
We can resolve this by simply changing the operator a less than symbol, < . This prevents the loop from looping over the index from going out of range.
Are you trying to display data from database to datagridview? Why not use databind?
See my sample code:
string connStr = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=the directory or the path of your database";
string query = "SELECT * From Table Name";
using (OleDbConnection conn = new OleDbConnection(connStr))
{
    using (OleDbDataAdapter adapter = new OleDbDataAdapter(query, conn))
    {
        DataSet ds = new DataSet();
        adapter.Fill(ds);
        dataGridView1.DataSource = ds.Tables[0];
    }
    conn.Close();
}
                        The Rows collection has an 'Add' method that takes an object array. It is definitely a simpler and more straightforward approach that the code sample in your question:
http://msdn.microsoft.com/en-us/library/fbs04kbx.aspx
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