how to handle null table linkq

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its give error for "The null value cannot be assigned to a member with type System.Int32 which is a non-nullable value type."

Here, i have Null table 'Rate'
and i wont to get max no. of rate.id (primary and Auto Increment).
here problem is that if table is Empty then it's show Error
how can i handle it

C#

DataClasses1DataContext dm = new DataClasses1DataContext();
var item = dm.Rates.Max(o => o.Id);
 item = (item) + 1;
    
lblSrno.Containt=item.Tostring();

please help me

Posted 13-Nov-14 18:20pm

mukesh mourya

Updated 14-Nov-14 6:02am

v3

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Comments

BillWoodruff 14-Nov-14 2:23am

It's good programming practice to check for 'null before executing code that will rely on a non-null "something."

4 solutions

Solution 3

Hi,

You can write like this

C#

try
{
DataClasses1DataContext dm = new DataClasses1DataContext();
var item = dm.Rates.Max(o => o.Id);
if(item==null)return;
 item ++;
lblSrno.Containt=item.Tostring();
}
catch{

}

Check it whether it is working for you..

Posted 13-Nov-14 20:54pm

Jineesh TR

Comments

mukesh mourya 14-Nov-14 12:22pm

It's not work

Jineesh TR 16-Nov-14 22:28pm

then you check null for dm.Rates. I think this is null.

Solution 2

C#

DataClasses1DataContext dm = new DataClasses1DataContext();
var item = dm.Rates.Max(o => o.Id);
 item = (item==null ? 0:item) + 1;
lblSrno.Containt=item.Tostring();

Posted 13-Nov-14 20:06pm

Pravuprasad

Comments

mukesh mourya 14-Nov-14 12:37pm

Not worked

Solution 1

You can try the below code.

var item = dm.Rates.Max(o => {if(o!=null && o.id!=null){ return o.id; } });

Posted 13-Nov-14 18:37pm

ashish__shukla

Comments

mukesh mourya 14-Nov-14 12:22pm

It's not work :(

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/\jmot · Accepted Answer · 2014-11-13T21:08:00

Solution 4

Try this...

C#

int? intIdt = db.Users.Max(u => (int?)u.UserId);

See this link for Explanation.
Null MaxId[^]

Posted 13-Nov-14 21:08pm

/\jmot