从文本文件中移动带有点列表的对象

我试图将我的多维数据集从一个点移动到一个文本文件中的坐标点。

public class cube : MonoBehaviour
{
    // Speed
    public float speed = 3.0f;

    // Start is called before the first frame update
    void Start()
    {
       print("cube says hi");

    }

    // Update is called once per frame
    void Update()
    {

        string path = "Assets/Ressources/test.txt";
        var sr = new StreamReader(path);
        List<string> columnx = new List<string>();
        List<string> columny = new List<string>();
        List<string> columnz = new List<string>();

        using (sr)
        {
            while (!sr.EndOfStream)
            {
                string line = sr.ReadLine();
                var values = line.Split(new string[] { "      " }, System.StringSplitOptions.RemoveEmptyEntries);

                columnx.Add(values[0]);
                columny.Add(values[1]);
                columnz.Add(values[2]);

            }


        }


        float step = speed * Time.deltaTime;
        transform.position = Vector3.MoveTowards(transform.position,
                                            new Vector3(
                                                Convert.ToSingle("1.45", CultureInfo.InvariantCulture), Convert.ToSingle("3.258", CultureInfo.InvariantCulture), Convert.ToSingle("4.256", CultureInfo.InvariantCulture)
                                            ), step);

    }

}

这可行，但是问题是当我用columnx [0] columny [0]和columnz [0]替换“ 1.45”，“ 3.25”和“ 4.25”时，

FormatException: Input string was not in a correct format.
System.Number.ParseSingle (System.String value, System.Globalization.NumberStyles options, System.Globalization.NumberFormatInfo numfmt) (at <437ba245d8404784b9fbab9b439ac908>:0)

我想用第一个元素进行测试，以便可以进行for循环，但是甚至不能使用0。