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Datagridview will not react to a cell click event unless header column is clicked, why?

So I have a datagridview that auto generates columns based on the data I pull from a database. Now I also have a cell click event for the datagridview, however this event only fires if the column header is click. It will not fire if I click any of the cells populated inside the datagridview, why?
// This is in the designer code
this.dgvScheduled.CellClick += new System.Windows.Forms.DataGridViewCellEventHandler(this.dgvScheduled_CellClick);
// This is in my main forms application
private void dgvScheduled_CellClick(object sender, DataGridViewCellEventArgs e)
{
ChangeIsNoShow(e);
}
With the event subscribed in the designer code and the event in the application, it does not make sense why it does not execute when I click on cell that is not the header cell.

Creating a custom definition/property for a control

I'm currently about to design a project that uses a DataGridView. As one of the events I would like it to perform a task upon double-clicking on a row.
Looking around I can find examples of creating your own event, however I notice that DataGridView has no property or definition for double-clicking a row, and was wondering how I could specify this myself?

There's a CellMouseDoubleClick event that, in contrast to the "normal" DataGridView's mouse double click event, fires only when the user actually double-clicks the cell of a row.
About the question on how to do it yourself: You could try to derive a new class from DataGridView, attach the CellMouseDoubleClick event internally and just fire a new event, passing the clicked row. For example:
private void DataGridView1_CellMouseDoubleClick(Object sender, DataGridViewCellMouseEventArgs e)
{
// Determine the row the clicked cell belongs to
...
// Fire a new event for that row
...
}

DataGridView make Cells unselectable

Hi I have c# datagridview and everytime when I hit TAB i got focused cell in my datagridview. Does anyone know how to deny focusing cells in datagridview? I need to mark only row not cells.
Thank you

I see the problem. You're taking about focus rectangle. You can prevent it by subscribing RowPrePaint event and remove the focus PaintPart.
private void dgv_RowPrePaint(object sender, DataGridViewRowPrePaintEventArgs e)
{
e.PaintParts &= ~DataGridViewPaintParts.Focus;
}
Original answer

DataGridView that always has one row selected

I'm using a DGV to show a list of images with text captions as a picklist. Their must always be a one and only one selection made in the list. I can't find a way to prevent the user from clearing the selection with a control-click on the selected row.
Is there a property in the designer I'm missing that could do this?
If I have to override the behavior in the mouse click events are there other ways the user could clear the current selection that need covered as well?
Is there a third approach I could take that's less cumbersome than my second idea?

The easiest way is to catch the SelectionChanged event and check to see if the user has unselected all rows. If so, reselect the previously selected row. Essentially, you're intercepting their action and switching the selection back. Something like this (code untested but you will get the idea):
DataGridViewRow last_selected_row;
private void dgv_SelectionChanged(object sender, EventArgs e)
{
if (dgv.SelectedRows.Count == 0)
last_selected_row.Selected = true;
else
last_selected_row = dgv.SelectedRows[0];
}
Depending on your application, it might be better to store the row index rather than a reference to the row itself. Also be sure to initialize last_selected_row and update it if you delete any rows.
Any other controls that hook the SelectionChanged event will need to safely handle the case that no rows are selected, in case they fire before the event that switches it back. They can just return immediately though, safe in the knowledge that SelectionChanged will fire again momentarily.
You could also subclass DataGridView and override the OnSelectionChanged method. Then you could reselect the last selected row before the event fires (it will fire when you call base.OnSelectionChanged).

A DGV got a property called multiselect, if you set it to false only one cell/row can be selected at a time.

Just handle the DataBindingComplete event of the datagridview like this:
private void datagridview1_DataBindingComplete(System.Object sender, System.Windows.Forms.DataGridViewBindingCompleteEventArgs e)
{
datagridview1.ClearSelection();
}

DatagridView Checkbox Checked?

i have a check box in a datagridview windows form and have a event handler cell_Click
on cell click i check the datagridview column for a check box it shows true if the cell is selected too(that is the check box is unchecked and only the the datagrid view cell is selected) and the check box is not selected .i tried for the column gettype and found out the type it shows DatagridViewCheckBox but wrong checked values .???

If I understand you correctly you are saying the checkbox value does not align with the underlying data?
This may well be because the data has been updated and is 'dirty', e.g. it hasn't been committed to the datasource yet. If you add an event handler like this:
private void dataGridView1_CurrentCellDirtyStateChanged(object sender, EventArgs e)
{
if (dataGridView1.CurrentCell is System.Windows.Forms.DataGridViewCheckBoxCell)
{
dataGridView1.CommitEdit(DataGridViewDataErrorContexts.Commit);
}
}
Then that should update the datasource and you'll have the correct checkbox state when you query the cell.

Several things here:
the cell click event just means that the user clicked with the mouse button on the data grid view, what you're looking for is probably the CellValueChanged
this event will give you the coordinates of the cell that changed. You should check to see if it's in your check box column, then get a reference to the cell and you can check the cell.Value to see if it's true or false. You're not going to find any values on the DataGridViewCheckBoxColumn -- it's going to be at the cell level, and you'll always find the value stored in cell.Value, no matter what type of column it is.