Databases :: MySQL - CSharp To Assign Null Date Time To A Class Field?

Using MySQL 5.

In my SAP.NEt project, defined a constant:

public static DateTime NullDateTime = DateTime.MinValue;

I have a function:

protected static DateTime GetDateTime(DataRow row, string columnName)
{
return (row[columnName] != DBNull.Value) ?
Convert.ToDateTime(row[columnName]) :
Globals.NullDateTime;
}

In the source code:

public DateTime StationFeedTime{ get; set; }
StationFeedTime = GetDateTime(row, "StationFeedTime");

I ran a SQL to fetch records from MySQL, this field is Time field in MySQL.

Got an exception inside the function:

Unable to cast object of type 'System.TimeSpan' to type 'System.IConvertible'.