C#读取txt数据到一个二维数组

private void button1_Click(object sender, EventArgs e)
{
if (openFileDialog1.ShowDialog() != DialogResult.Cancel)
{
FileName = openFileDialog1.FileName;
System.IO.StreamReader readfile = new System.IO.StreamReader(FileName);
readfile.BaseStream.Seek(0, System.IO.SeekOrigin.Begin);
int line_total=0;//总行数

while (readfile.ReadLine() != null)
{
line_total++;
}

textBox3.Text = line_total.ToString();

readfile.BaseStream.Seek(0,System.IO.SeekOrigin.Begin);
//  string line = readfile.ReadLine();

List<string[]> list = new List<string[]>();

while (!readfile.EndOfStream)
{

string[] line = readfile.ReadLine().Split(' ');
string[] arr = new string[line.Length];
for (int i = 0; i < line.Length; i++)
{
arr[i] = Convert.ToString(line[i]);

}
list.Add(arr);
}

string[][] shuzu = list.ToArray();

textBox4.Text = shuzu[0][5];
//显示指定数据，此程序不能用shuzu[0,5],还没搞懂原因

}
else
return;
}