How to do multiple split values from a list of string to an object, blows if there is no string to split

howto do multiple split values from a list of string to an object, Blows if there is no string to split

I want to split this

List<string> CrossReference = new List<string>
    {
         "task #1443; task #1447; task #1444; task #973; rel #33; sprint #815",
         ""
    };

First by

;

then by

#

I have this class

public class CrossReference
{
    public long Aid { get; set; }
    public string TaskType { get; set; }
}

and I have this test

[TestMethod]
public void splitTest()
{
    List<string> CrossReference = new List<string>
    {
         "task #1443; task #1447; task #1444; task #973; rel #33; sprint #815",
         ""
    };

    foreach (var str in CrossReference)
    {
        var str1 = str.Trim().Split(';')
                    .Select(x => new CrossReference
                    {
                        TaskType = (string)x.Split(new char[] { '#' }, StringSplitOptions.RemoveEmptyEntries)[0],
                        Aid = Convert.ToInt64(x.Split(new char[] { '#' }, StringSplitOptions.RemoveEmptyEntries)[1]),
                    }).ToList();
    }
}               

The value of str1 in the first run is ok, but in the second run blows up because I don´t have anything to split.

How can I prevent the case that there is no string to split.

Thanks in advance

Jolynice