Compare columns of DataGridView

samanta

12y1.6k.NET

i am using dataGridView with 4 columns.

like this:

id	name	num	name2
1	aaa	4	ddd
2	bbb	6	null
3	ccc	1	aaa
4	ddd	5
5	eee	2
6		3

i want to compare id and num columns so that respective value must be display in name2 column

14 Replies

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Vulpes12y ago
Ah, it sounds like you have a blank row at the bottom of the DGV for adding new records.

See if inserting the highlighted line gets rid of the exception:

foreach (DataGridViewRow row in dataGridView1.Rows)
{
if(row.IsNewRow) break;
int num = Convert.ToInt32(row.Cells["num"].Value.ToString());
if (num <= dataGridView1.Rows.Count)
{
object name = dataGridView1.Rows[num - 1].Cells["name"].Value;
row.Cells["name2"].Value = name;
}
}
samanta12y ago
last row of id column not have any value
Vulpes12y ago
Are there any rows which don't have a value in the 'num' column?

Also is it safe to assume that all rows will have a value in the id column and that the id's will be consecutive starting from 1 ?
samanta12y ago
giving error as

Object reference not set to an instance of an object.
Vulpes12y ago
It must be a string column in that case.

So I'd try replacing:

int num = (int)row.Cells["num"].Value;

with:

int num = Convert.ToInt32(row.Cells["num"].Value.ToString());
samanta12y ago
actually i am fetching data from excel sheet to datagridview so its giving error as

Specified cast is not valid.
Vulpes12y ago
Assuming that the name2 column isn't databound, try this code:

foreach (DataGridViewRow row in dataGridView1.Rows)
{
int num = (int)row.Cells["num"].Value;
if (num <= dataGridView1.Rows.Count)
{
object name = dataGridView1.Rows[num - 1].Cells["name"].Value;
row.Cells["name2"].Value = name;
}
}
samanta12y ago
when i click on button num2 column must contain items of name with respect to num column
samanta12y ago
sir can u write code so that i can understand clearly.
Munesh Sharma12y ago
http://social.msdn.microsoft.com/Forums/windows/en-US/c6f2daec-8e49-4137-94cb-764ed2d427aa/click-event-on-datagridviewbuttoncolumn

but you have to do some changes here see this.
samanta12y ago
yes sir,,,,,
Munesh Sharma12y ago
so you want to compare this at button click event.
samanta12y ago
its not possible to do when i click on button?
Munesh Sharma12y ago
http://stackoverflow.com/questions/13259013/compare-2-different-columns-in-the-datagridview