VB 10 : how to check null value in datagridview cells

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hi, i want to test/check when cells in data gridview is empty and when clicked it shows label like "there's a empty data in cell", thanks before

VB

If dgvdatakaryawan.Item(e.ColumnIndex, e.RowIndex).Value.ToString.Length = Nothing Then
           lblKET.Visible = True
       Else
           lblKET.Visible = False
       End If

i mean i have lot of data, if in one rows have some blank data, and when rows is clicked it show label like above

Posted 14-Jun-15 21:50pm

Akbar Giffary

Updated 10-Sep-17 9:44am

v3

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Andy Lanng 15-Jun-15 4:13am

Your question is very vague. Please at least post what you have tried so far.

Akbar Giffary 15-Jun-15 4:33am

take a look please

Andy Lanng 15-Jun-15 4:42am

Ok. I see. When does this segment run? is it in the page load?
Thanks ^_^

Akbar Giffary 15-Jun-15 5:00am

in mouseclick on datagridview

Andy Lanng 15-Jun-15 5:13am

Ah. datagrid views can be tricky with this. I had an issue with this on Friday.

What can happen is that the mouseclick event occurs before the datagrid data is bound. This would mean that the label is empty by the time you read it.

There are ways around this but first, please confirm that the bind event occurs after the mouseclick event.

Akbar Giffary 15-Jun-15 5:42am

okay so..
i'll explain my actual problem,

when i click in empty column the message of label is show..

but what i want is, the message only show when i selected the row with some blank data in column, is it possible ?

here my code i've tried

If
dgvdatakaryawan.SelectedRows('does not know the contents).Value.ToString.Length = Nothing Then

so can you complete that ?

Andy Lanng 15-Jun-15 5:54am

oh ok. Thanks for clarifying.
The code you posted looks ok. Do you know why that doesn't work? If not, what are the values of e.columnindex and e.rowindex at this time?

Akbar Giffary 15-Jun-15 6:02am

i think the values of e.columnindex and e.rowindex is member of datagridview, just like A1, A3 in excel

Andy Lanng 15-Jun-15 6:04am

What I meant was, can you debug the emptycell.click and tell me what the actual values are in that instance.

BTW: they will be zero indexed integers. i.e. 0 to max-1

Richard Deeming 15-Jun-15 8:12am

If .Value is Nothing, then .Value.ToString() will throw a NullReferenceException.

If .Value is not Nothing, then .Value.ToString().Length will return an Integer. An Integer will never be equal to Nothing.

Akbar Giffary 15-Jun-15 9:39am

hmmm, thanks for explanation...

so can you give me some help, please ?
how do i check null value when i select the Rows ?
i mean the message only show when i selected the row with some blank data in cells, is that possible ?

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Mike Meinz · Accepted Answer · 2015-06-15T05:06:00

Solution 1

I think your If statement should look like this. It sets the lblKET to visible if the cell is Null or contains only spaces or an empty string.

VB

If dgvdatakaryawan.Item(e.ColumnIndex, e.RowIndex).Value Is Nothing orelse _
   dgvdatakaryawan.Item(e.ColumnIndex, e.RowIndex).Value.ToString.Trim = "" Then
     lblKET.Visible = True
Else
     lblKET.Visible = False
End If

Posted 15-Jun-15 5:06am

Mike Meinz

Updated 15-Jun-15 5:25am

v4

Comments

Akbar Giffary 15-Jun-15 20:50pm

hmmm, many thanks,
but can i sets the lblKET to visible if the "selected rows" have some Null value or contains only spaces or an empty string ?

i mean when if i selected rows, not when cell is clicked..

Mike Meinz 16-Jun-15 6:36am

If you want to select based on empty row, then you have to check each cell in that row. To do that, you iterate through all of the columns in that row and if they all satisfy the conditions in my sample code, then the row is "empty."