CODEWITHSUNDEEP
c#.netwinformsdatatabledatarow
rockyashkumar
rockyashkumar

Reputation: 1332

how to check every value in row of datatable using c#

I have two tables called visits and members and i am getting the data by using following query..

 string sql=  @"SELECT member_Firstname, member_Lastname, member_Postcode,  
          visit_DateTime, visit_Status, visit_Logout_DateTime, visits.member_Id, visit_AlertMsg
          FROM members, visits
          WHERE members.member_Id = visits.member_Id
          AND members.member_Active LIKE 'y%'";

at here i am getting the visit_DateTime values with by using some comparisons with combobox values 

    datatable dt = helper.getdata(sql)
     foreach (DataRow row in dt.Rows)
     {
         if (row["visit_Logout_DateTime"] != null)
         {
          DateTime dtlogout = DateTime.Parse(row["visit_Logout_DateTime"].ToString());
          if (dtlogout != null)
          {
            if (cbPeriod.Text == "Today")
            {
              newItem.lblTime.Text = dtlogout.ToString("HH':'mm':'ss");

            }
            else
              newItem.lblTime.Text = dtlogout.ToString("yyyy'-'MM'-'dd'  -  'HH':'mm':'ss");
          }
        }

     }

but i got the error at this line DateTime dtlogout = DateTime.Parse(row["visit_Logout_DateTime"].ToString());

error : string was not recognised as valid datetime (because of one value in that row is empty)

the row "visit_Logout_DateTime"

i have got the values of "visit_Logout_DateTime" like this....

firstname     lastname   postcode      visit_Logout_DateTime
-------------  --------   ---------      ---------------------
 rob            peter     hhd344h            
 peter         chan        hy78kjk         2011-09-08 12:09:08
 rock          sam        yudufg3746h      2011-08-08 09:08:45

i have tried that for checking the empty values of this visit_Logout_DateTime like i mentioned above..

but i have failed for chacking ever value is empty or not in that row...

how to check every value in this row (row["visit_Logout_DateTime"]) is empty or not

would any one pls help me on this guys ...

many thanks....

Upvotes: 1

Views: 17575

Answers (5)

Gareth Wilson
Gareth Wilson

Reputation: 853

To expand on Kristof's answer you could look at extension methods to tidy the code up a little;

 public static DateTime? GetDate( this DataRow Row, string ColumnName )
    {

        object Value = Row[ ColumnName ];

        if( Value == DBNull.Value )
            return null;
        else
            return (DateTime)Value;

    }

// Repeat for other types, or use a generic version.
...

DateTime? dtlogout = row.GetDate("visit_Logout_DateTime");

Note the use of the Nullable DateTime (trailing ?) so that it can accept nulls.

Upvotes: 0

NaveenBhat
NaveenBhat

Reputation: 3328

You can use DateTime.TryParse like this:

DateTime date = new DateTime();

if (DateTime.TryParse(row["visit_Logout_DateTime"], out date))
            dtlogout = date;

Upvotes: 1

Denis Mazourick
Denis Mazourick

Reputation: 1455

First thing - use TryParse, not Parse to parse values when you're not sure whether the value will be a valid object or not.

For checking all values, try the following code example for checking each value:

        DataTable dt = new DataTable("MyTable");

        foreach (DataRow row in dt.Rows)
        {
            foreach (DataColumn column in dt.Columns)
            {
                if (row[column] != null)
                {
                    string value = row[column].ToString();
                    if (!String.IsNullOrEmpty(value))
                    {
                        // Do something
                    }
                }
            }
        }

Upvotes: 1

Nikola Radosavljević
Nikola Radosavljević

Reputation: 6911

You cannot check row against null. You should compare to DBNull.Value. So, either go with:

row["visit_Logout_DateTime"] != DBNull.Value

or

!string.IsNullOrEmpty(row["visit_Logout_DateTime"].ToString())

Upvotes: 0

Kristof Claes
Kristof Claes

Reputation: 10941

Instead of checking if the column is null, you should check if the contents of the column are null. You can do that by comparing it to DBNull.Value:

if (row["visit_Logout_DateTime"] != DBNull.Value)
{
    ...
}

Upvotes: 4

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