Set DataGridViewCheckBoxColumn default Value

Hi expert,

I try to use DataGridView in a winform app. I added DataGridViewCheckBoxColumn.
I'd like to set all checkbox default value as false.

I use the DefaultValuesNeeded event but not working.

Then I try to use a loop. It worked. But It's very slow.
It only changed 20-30 rows in 10 seconds. There are thousands rows in the datagridview.
So the performance is not acceptable. Please help. Appreciated!!

Please check code from attachment.
expertexchange.txt
jssong2000Asked:
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jssong2000Connect With a Mentor Author Commented:
I found a solution:

checkColumn.ThreeState = false;
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CodeCruiserCommented:
So is it defaulting to true currently?
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jssong2000Author Commented:
If I don't setup. The default value is null.
User has to click two times to make it checked. It's inconvenient.
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Jacques Bourgeois (James Burger)PresidentCommented:
Add a column to the table first. This could be done at the SQL level with a Select such as this one:

SELECT False AS Col1, Field1, Field2,...

Or add it to the DataTable in memory If you cannot add it to the SQL for some reason.

If you cannot do either, then you might consider the fact that the DataGridView events are often tricky to work with. For instance, when you fill a DataGridView, the validating events are often triggered uselessly, because one can assume that the data was already verified before it was stores in the database that provides the DataTable.

You might thus look at the events that are triggered when by your code, and deactivate it before you run it:

this.dataGridView1.RowValidating -= new System.Windows.Forms.DataGridViewCellCancelEventHandler(this.dataGridView1_RowValidating);
this.dataGridView1.CellValidating -= new System.Windows.Forms.DataGridViewCellValidatingEventHandler(this.dataGridView1_CellValidating);
...

Run your code without the events, then add them back so that they are ready to trigger when the user starts interacting with the grid:

this.dataGridView1.RowValidating += new System.Windows.Forms.DataGridViewCellCancelEventHandler(this.dataGridView1_RowValidating);
this.dataGridView1.CellValidating += new System.Windows.Forms.DataGridViewCellValidatingEventHandler(this.dataGridView1_CellValidating);
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jssong2000Author Commented:
I found a solution.
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