C# Exception handling

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I am wondering if there is a more eloquent way to express the code below? I can't seem to get the IsNullOrEmpty method to work with data inside of a DataGridView so whenever a cell is null an exception is thrown.

This works, but it seems to be a bit of a work around (maybe not) and I have the same issue when checking the value of a checkbox in the grid which caused me to write more code for that work around.

Any suggestions are greatly appreciated.

C#

private bool IsRowValid( DataGridViewRow row )
{
    bool retVal = false;
    try
    {
        if( ( string.IsNullOrEmpty( row.Cells[ "Quantity" ].Value.ToString() ) != true ) &&
            ( string.IsNullOrEmpty( row.Cells[ "Unit" ].Value.ToString() ) != true ) &&
            ( string.IsNullOrEmpty( row.Cells[ "Cell" ].Value.ToString() ) != true ) &&
            ( string.IsNullOrEmpty( row.Cells[ "Station" ].Value.ToString() ) != true ) )
        {
            retVal = true;
        }
    }
    catch( NullReferenceException )
    {
        retVal = false;
    }
    return retVal;
}

Posted 4-Nov-10 12:00pm

Jeff Patterson

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2 solutions

Solution 1

I don't know of a more elegant way, although somebody probably will.

The only thing I would say is that it could be very slightly shorter

C#

if ( ( !string.IsNullOrEmpty( row.Cells[ "Quantity"].Value.ToString() )) &&
   ( !string.IsNullOrEmpty( row.Cells[ "Unit"].Value.ToString() )) &&
   ( !string.IsNullOrEmpty( row.Cells[ "Cell"].Value.ToString() )) &&
   ( !string.IsNullOrEmpty( row.Cells[ "Station"].Value.ToString() )) )

possibly at the expense of readability.

Posted 4-Nov-10 12:14pm

Henry Minute

Comments

Jeff Patterson 5-Nov-10 10:29am

You are right and with Nishant's null suggestion I have something that works better reads clearer.

Thank you

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Nish Nishant · Accepted Answer · 2010-11-04T12:14:00

Solution 2

The problem in that code is that row.Cells[ "Quantity" ].Value can be null, but you call ToString on that without checking for that.

Change:

C#

string.IsNullOrEmpty( row.Cells[ "Quantity" ].Value.ToString() )

to

C#

string.IsNullOrEmpty( row.Cells[ "Quantity" ].Value as String)

Btw please don't do != true, that's ugly to see and not recommended practice. Instead do this:

C#

if( !String.IsNullOrEmpty(...))...

Posted 4-Nov-10 12:14pm

Nish Nishant

Updated 4-Nov-10 12:18pm

v3

Comments

Jeff Patterson 5-Nov-10 10:27am

Thank you!
Your sample explains to me why my initial check for null (not shown) didn't work. This is far better.

I agree that !=true is ugly. I will implement both of your suggestions. Again thank you.

Nish Nishant 5-Nov-10 10:29am

Np, you are welcome.