Solved

Set DataGridViewCheckBoxColumn default Value

Posted on 2014-02-14
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Last Modified: 2014-02-19
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
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Question by:jssong2000
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Expert Comment

by:CodeCruiser
Comment Utility
So is it defaulting to true currently?
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Author Comment

by:jssong2000
Comment Utility
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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LVL 40

Expert Comment

by:Jacques Bourgeois (James Burger)
Comment Utility
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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Accepted Solution

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jssong2000 earned 0 total points
Comment Utility
I found a solution:

checkColumn.ThreeState = false;
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Author Closing Comment

by:jssong2000
Comment Utility
I found a solution.
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