c# - 如何修复索引超出范围错误

Question

如何修复这个错误:

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

在这段代码中:

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();

Answer 1

您是否正在尝试将数据从数据库显示到 datagridview？为什么不使用 databind？

查看我的示例代码:

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();
}