IQueryable 转化为DataTable

1:要属性是否可以为空System.Nullable`1[]

2:string  属性不为空

public static class ExtendIQueryable

{
   
    public static DataTable ConvertToDataTable(System.Linq.IQueryable o)
    {
        DataTable  dt= new DataTable();
        var props = o.ElementType.GetProperties();
        foreach (System.Reflection.PropertyInfo pi in props)
        {

            string ddd = pi.PropertyType.ToString();

　　　　

            if ((pi.PropertyType == System.Type.GetType("System.Nullable`1[System.Int32]")) || (pi.PropertyType == System.Type.GetType("System.Int32")))
            {
                dt.Columns.Add(pi.Name, System.Type.GetType("System.Int32"));
            }
            else if (pi.PropertyType == System.Type.GetType("System.String"))
            {
                dt.Columns.Add(pi.Name, System.Type.GetType("System.String"));
            }
            else if ((pi.PropertyType == System.Type.GetType("System.Nullable`1[System.DateTime]")) ||  (pi.PropertyType == System.Type.GetType("System.DateTime")))
            {
                dt.Columns.Add(pi.Name, System.Type.GetType("System.DateTime"));
            }
            else
            {
                dt.Columns.Add(pi.Name, System.Type.GetType("System.Decimal"));
            }
            
        }
        foreach (var item in o)
        {
            DataRow dr = dt.NewRow();
            foreach (System.Reflection.PropertyInfo pi in props)
            {
                if (pi.GetValue(item,null) != null)
                {
                    if (pi.GetValue(item,null) != null)
                    {
                        dr[pi.Name] = pi.GetValue(item,null);
                    }
                }
            }
            dt.Rows.Add(dr);
        }
        return dt;
    }