How do you bypass cells in a "DataGridView"

[Michael Torville]

Does anyone know if it's possible to prevent a user from entering a
particular "DataGridView" cell. I simply want to redirect them into the next
available cell but nothing I try works. Setting the "CurrentCell" property
for instance causes no end of problems. If I call it in a "CellEnter"
handler I get the error "Operation is not valid because it results in a
reentrant call to the SetCurrentCellAddressCore function" (which others on
the web have also reported). If I call it in a "CellMouseDown" handler it
works when right-clicking but not left-clicking. In other handlers it causes
a stack overflow. Does anyone know how to pull this off. Thanks.

 

[justin creasy]

Does anyone know if it's possible to prevent a user from entering a
particular "DataGridView" cell. I simply want to redirect them into the next
available cell but nothing I try works. Setting the "CurrentCell" property
for instance causes no end of problems. If I call it in a "CellEnter"
handler I get the error "Operation is not valid because it results in a
reentrant call to the SetCurrentCellAddressCore function" (which others on
the web have also reported). If I call it in a "CellMouseDown" handler it
works when right-clicking but not left-clicking. In other handlers it causes
a stack overflow. Does anyone know how to pull this off. Thanks.

Michael:

I have a few thoughts. First, have you set the DataGridView's
MultiSelect, SelectionMode, or EditMode attributes or left them on
their default settings? If you could show us your code for when you
create your DataGridView and when you set it's attributes that would
help.

I agree that using the CellEnter event is a bad idea since that could
cause an infinite loop. I cannot replicate your problem with left
clicked when using the CellMouseDown event. I have tried using both
the CellMouseDown and the CellMouseClick events and they both register
for left-click and right-click. I'm hoping that once I know how you
have your attributes set I will be able to replicate your problem. If
possible please also supply your code for the CellMouseDown event.

~ Justin Creasy
www.immergetech.com
www.immergecomm.com

 

[ClayB]

Here is some code that postpones setting the current cell using a
timer in CellEnter to prevent cell 2,2 becoming current. There is a
flash when you try clicking, but the arrow keys and tab keys seem to
work better.

private int skipRow = 2;
private int skipCol = 2;
private int oldRow = -2;
private int oldColumn = -2;

void dataGridView1_CellEnter(object sender,
DataGridViewCellEventArgs e)
{
if (e.RowIndex == skipRow && e.ColumnIndex == skipCol)
{
if (Control.MouseButtons == MouseButtons.None)
{
if (oldRow == skipRow - 1 && oldColumn == skipCol)
{
oldRow = skipRow + 1;

}
else if (oldRow == skipRow && oldColumn == skipCol
- 1)
{
oldColumn = skipCol + 1;
}
else if (oldRow == skipRow + 1 && oldColumn ==
skipCol)
{
oldRow = skipRow - 1;

}
else if (oldRow == skipRow && oldColumn == skipCol
+ 1)
{
oldColumn = skipCol - 1;
}
}
Timer t = new Timer();
t.Interval = 5;
t.Tick += new EventHandler(t_Tick);
t.Start();
}
}

void t_Tick(object sender, EventArgs e)
{
Timer t = sender as Timer;
t.Stop();
this.dataGridView1.CurrentCell =
this.dataGridView1[oldColumn, oldRow];
t.Tick -= new EventHandler(t_Tick);
}

void dataGridView1_CellLeave(object sender,
DataGridViewCellEventArgs e)
{
oldRow = e.RowIndex;
oldColumn = e.ColumnIndex;
}
==============
Clay Burch
Syncfusion, Inc.

 

[Michael Torville]

I have a few thoughts. First, have you set the DataGridView's

MultiSelect, SelectionMode, or EditMode attributes or left them on
their default settings? If you could show us your code for when you
create your DataGridView and when you set it's attributes that would
help.

Thanks for the feedback. I've have in fact set all of the above using the VS
forms designer so it all takes place in "InitializeComponent()"

MultiSelect = false
SelectionMode = CellSelect
EditMode = EditOnKeystrokeOrF2

I agree that using the CellEnter event is a bad idea since that could
cause an infinite loop.

I've taken precautions against this. The error I cited previously however
appears to be a bug not only because I've read about others who have the
same problem, but because the manager of the "DataGridView" class at MSFT
(Mark Rideout) acknowledged it's a bug under other circumstances (on the
MSFT forums site).

I cannot replicate your problem with left
clicked when using the CellMouseDown event. I have tried using both
the CellMouseDown and the CellMouseClick events and they both register
for left-click and right-click. I'm hoping that once I know how you
have your attributes set I will be able to replicate your problem. If
possible please also supply your code for the CellMouseDown event.

Well, I just tried this by creating a new app out-of-the-box. I added a
"DataGridView" as the only control on the form with two textbox columns. I
then created a "CellMouseDown" handler as follows:

private void m_Grid_CellMouseDown(object sender,
DataGridViewCellMouseEventArgs e)
{
if (e.ColumnIndex == 0)
{
m_Grid.CurrentCell = m_Grid[1, 0];
}
}

When the app starts, column 0 is automatically the current column. If I now
right-click column 0 then the handler is called (just once) and column 1
becomes current as expected. If I left-click column 0 however then the
handler is also called (just once) but column 0 remains current. I can
understand why this is probably occurring (left-clicking makes the cell
current *after* the handler exits) but it's incorrect behaviour IMO (since
the handler's code should override the left-mouse click). Any ideas? Thanks.

 

[Michael Torville]

Thanks. I'll take a look at this but in all honesty, the timer makes me
nervous. I'm not sure why a timer is needed here but I'll reserve judgment
until I review it Thanks again.