Are you looking at recording the X, Y, Z data of the skeleton into a text file? It is generally easier to record the information separately in readable format. If you are looking at doing the aforementioned then this may help:
//save the XYZ of the skeleton data, but also save the XZ of depth data
private void saveCoordinates(Skeleton skeleton, string textFile)
{
StreamWriter coordinatesStream = new StreamWriter(newPath + "\\" + textFile);
foreach (Joint joint in skeleton.Joints)
{
coordinatesStream.WriteLine(joint.JointType + ", " + joint.TrackingState + ", " + joint.Position.X + ", " + joint.Position.Y + ", " + joint.Position.Z);
}
coordinatesStream.Close();
}