DatagridView 选择最后一行

Question

I have some trouble with setting the last row in my datagridview selected. I select the last row this way:

if (grid.Rows.Count > 0)
{
    try
    {
        grid.Rows[grid.Rows.Count - 1].Selected = true;
        grid.CurrentCell = grid.Rows[grid.Rows.Count - 1].Cells[1]
    }
    catch (IndexOutOfRangeException)
    { }
    catch (ArgumentOutOfRangeException)
    { }
}

When I execute this code I get an exception: IndexOutOfRangeException occurred : Index-1 does not have a value.

When I debug the Rows collection and the corresponding Cells collection I see both collections are filled. The index also exists of the Rows and Cells collection.

I have no clue what I am doing wrong here. Someone who can help me out here? Thnx

EDIT:

Here is the complete exception:

System.IndexOutOfRangeException: Index -1 does not have a value.
at System.Windows.Forms.CurrencyManager.get_Item(Int32 index)
at System.Windows.Forms.CurrencyManager.get_Current()
at System.Windows.Forms.DataGridView.DataGridViewDataConnection.OnRowEnter(DataGridViewCellEventArgs e)
at System.Windows.Forms.DataGridView.OnRowEnter(DataGridViewCell& dataGridViewCell, Int32 columnIndex, Int32 rowIndex, Boolean canCreateNewRow, Boolean validationFailureOccurred)
at System.Windows.Forms.DataGridView.SetCurrentCellAddressCore(Int32 columnIndex, Int32 rowIndex, Boolean setAnchorCellAddress, Boolean validateCurrentCell, Boolean throughMouseClick)
at System.Windows.Forms.DataGridView.set_CurrentCell(DataGridViewCell value)

Answer 1

Try:

dataGridView1.ClearSelection();//If you want

int nRowIndex = dataGridView1.Rows.Count - 1;
int nColumnIndex = 3;

dataGridView1.Rows[nRowIndex].Selected = true;
dataGridView1.Rows[nRowIndex].Cells[nColumnIndex].Selected = true;

//In case if you want to scroll down as well.
dataGridView1.FirstDisplayedScrollingRowIndex = nRowIndex;

Gives following output : (Last row, scrolled and selected)

Answer 2

I know this may be a little late but it may be of use to someone else.

Have you tried this :

grid.Rows.Row[grid.Rows.Count -1].Selected = true;

In my windows app I first used your code in my datagridview and I got the same exception.. and then it came to me at night when I was in my bed (I'm a newbie to programming).

If I write as : Rows[Rows.count-1] the first row is "0" and "0-1 = -1" so its out of range :)

Then when I changed my code to Rows.Row[index] it worked! :)

---

An alternative if you use c# 3.0 and higher: check out CellAddress(); ;)

Sincerely

Answer 3

Have you thought about using Linq for this?

    grid.Rows.OfType<DataGridViewRow>().Last().Selected = true;
    grid.CurrentCell = grid.Rows.OfType<DataGridViewRow>().Last().Cells.OfType<DataGridViewCell>().First(); // if first wanted

Answer 4

Your 'catch' block for IndexOutOfRangeException is empty, and will not display any error at all.

Either your question is not exact, or the exception is being thrown somewhere else.

EDIT: Having looked through your call stack that you added, I can see that the error is, indeed, not being thrown here, but rather in the CurrencyManager class's Current / Item properties, which is ultimately being triggered by the call to the CurrentCell setter.

Bottom line: the problem is not in this code; the exception is being thrown by some other piece of code triggered by your setting the current cell.

Answer 5

dataGridView1.Rows[dataGridView1.Rows.Count - 1].Selected = true;

Answer 6

Eventually the last row is empty because it's the empty row with which the user can add a new row. This row cannot be selected. Have you tried grid.Rows.Count - 2? As an alternative, you can set AllowUserToAddRows to false.

Answer 7

To avoid the IndexOutOfRangeException make sure only to select a visible row. I suggest:

// Find last visible row
DataGridViewRow row = dataGridView1.Rows.Cast<DataGridViewRow>().Where(r => r.Visible).Last(); 
// scroll to last row if necessary
dataGridView1.FirstDisplayedScrollingRowIndex = dataGridView1.Rows.IndexOf(row);
// select row
row.Selected = true;

Answer 8

It's very easy. use: dataGridView.CurrentCell=dataGridView[ColumnIndex, RowIndex];
dataGridView[X,y]...
instead of
dataGridView[Y, X]...