c# - how to convert date time if passing null value in date field -

how store null value , how insert null values in database? im getting error.

string not recognized valid datetime.

if (taskobj.estimatedtime == null) {     taskobj.estimatedtime = convert.todatetime(estimatetimelabel.text); }  public datetime estimatedtime {     set { estimatedtime = value; }     { return estimatedtime; } } 

you need specify in database can allow null specific column.

if have database can run like:

alter column `yourcolumn` datetime2() default null 

this allow use null in database.

you need convert datetime in code nullable type. otherwise .net comes out default date 1/1/0001 12:00:00 (not helpful).

there 2 ways this. recommend first it's purely down coding style.

you can either using ? operator:

 public datetime? estimatedtime {     set { estimatedtime = value; }     { return estimatedtime; } } 

or nullable generic function:

public nullable<datetime> estimatedtime {     set { estimatedtime = value; }     { return estimatedtime; } } 

don't forget convert estimatedtime field nullable type (again either using ? operator or nullable.

i hope helps. if not leave me comment , best assist you.