Compare columns of DataGridView

Question

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

Vulpes · Answer

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 { object name = dataGridView1.Rows[num - 1].Cells["name"].Value; row.Cells["name2"].Value = name; } }

Vulpes · Answer

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 { object name = dataGridView1.Rows[num - 1].Cells["name"].Value; row.Cells["name2"].Value = name; } }

samanta · Answer

last row of id column not have any value

Vulpes · Answer

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 ?

samanta · Answer

giving error as Object reference not set to an instance of an object.

Vulpes · Answer

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());

samanta · Answer

actually i am fetching data from excel sheet to datagridview so its giving error as Specified cast is not valid.

samanta · Answer

when i click on button num2 column must contain items of name with respect to num column

samanta · Answer

sir can u write code so that i can understand clearly.

Munesh Sharma · Answer

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.

samanta · Answer

yes sir,,,,,

Munesh Sharma · Answer

so you want to compare this at button click event.

samanta · Answer

its not possible to do when i click on button?

Munesh Sharma · Answer

http://stackoverflow.com/questions/13259013/compare-2-different-columns-in-the-datagridview