使用C＃DataGridView自定义选择

Question

I have a DataGridView with single text characters in it.. basically like Character Map, but want to be able to select groups of the cells left-to-right, as if it were text.

Ie the default behaviour if I select 2 cells vertically is for only those 2 cells to be selected. However, I want it to select all cells to the right of the top row, and to the left of the second row. Just like if you were to highlight two vertical characters in this question text.

Is it possible? (And have I managed to explain it in a way that makes sense?!)

Thanks!

EDIT: Added a couple of images to help explain this better.

Firstly, if I select 'P' and drag down to 'd', this is what gets selected:

What I would like to happen in this case, is this:

Hopefully this makes it more clear, thanks :)

Answer 1

This works, take a look

private void Form1_Load(object sender, EventArgs e)
    {
        dataGridView1.DataSource = li;
        dataGridView1.SelectionMode = DataGridViewSelectionMode.CellSelect;
        dataGridView1.SelectionChanged += dataGridView1_SelectionChanged;
    }

    private void dataGridView1_SelectionChanged(object sender, EventArgs e)
    {
        var la = dataGridView1.SelectedCells;
        if (la.Count == 2)
        {
            var rowFirst = ((DataGridViewCell)la[0]).RowIndex;
            var columnFirst = ((DataGridViewCell)la[0]).ColumnIndex;

            var rowSecond = ((DataGridViewCell)la[1]).RowIndex;
            var columnSecond = ((DataGridViewCell)la[1]).ColumnIndex;

            for (int column = 0; column <= columnFirst; column++)
            {
                dataGridView1[column, rowFirst].Selected = true;
            }

            for (int column = columnSecond; column < dataGridView1.ColumnCount; column++)
            {
                dataGridView1[column, rowSecond].Selected = true;
            }
        }
    }

Answer 2

Expanding on simple-thomas's answer with a more generic solution, I came up with this. It doesn't handle a shrinking selection very well, but it's good enough for my purposes. Thanks simple-thomas!

    private void characterGrid_SelectionChanged( object sender, EventArgs e )
    {
        if ( SelectionChanging == true )
        {
            return;
        }

        SelectionChanging = true;

        var la = characterGrid.SelectedCells;
        if ( la.Count > 1 )
        {
            var sorted = new List<DataGridViewCell>();
            System.Collections.IEnumerator enumerator = la.GetEnumerator();
            while ( enumerator.MoveNext() )
            {
                sorted.Add( (DataGridViewCell)enumerator.Current );
            }
            sorted.Sort( delegate( DataGridViewCell t1, DataGridViewCell t2 )
            {
                if ( t1.RowIndex != t2.RowIndex )
                {
                    return t1.RowIndex.CompareTo( t2.RowIndex );
                }
                else
                {
                    return t1.ColumnIndex.CompareTo( t2.ColumnIndex );
                }
            });

            var rowFirst = ( (DataGridViewCell)sorted[ 0 ] ).RowIndex;
            var columnFirst = ( (DataGridViewCell)sorted[ 0 ] ).ColumnIndex;

            var rowLast = ( (DataGridViewCell)sorted[ sorted.Count - 1 ] ).RowIndex;
            var columnLast = ( (DataGridViewCell)sorted[ sorted.Count - 1 ] ).ColumnIndex;

            if ( rowLast > rowFirst )
            {
                // select first row
                for ( int column = columnFirst; column < characterGrid.ColumnCount; column++ )
                {
                    characterGrid[ column, rowFirst ].Selected = true;
                }

                // in between
                for ( int row = rowFirst + 1; row < rowLast; row++ )
                {
                    for ( int column = 0; column < characterGrid.ColumnCount; column++ )
                    {
                        characterGrid[ column, row ].Selected = true;
                    }
                }

                // last row
                for ( int column = 0; column <= columnLast; column++ )
                {
                    characterGrid[ column, rowLast ].Selected = true;
                }
            }
        }

        SelectionChanging = false;
    }